Muscles A Medical Dictionary Bibliography and Annotated Research Guide to Internet References

Dictionary 343 greater than the normal atmospheric pressure. [NIH] Aerosol: A solution of a drug which can be atomized into a fine mist for inhalation therapy. [EU] Afferent: Concerned with the transmission of neural impulse toward the central part of the nervous system. [NIH] Affinity: 1. Inherent likeness or relationship. 2. A special attraction for a specific element, organ, or structure. 3. Chemical affinity; the force that binds atoms in molecules; the tendency of substances to combine by chemical reaction. 4. The strength of noncovalent chemical binding between two substances as measured by the dissociation constant of the complex. 5. In immunology, a thermodynamic expression of the strength of interaction between a single antigen-binding site and a single antigenic determinant (and thus of the stereochemical compatibility between them), most accurately applied to interactions among simple, uniform antigenic determinants such as haptens. Expressed as the association constant (K litres mole -1), which, owing to the heterogeneity of affinities in a population of antibody molecules of a given specificity, actually represents an average value (mean intrinsic association constant). 6. The reciprocal of the dissociation constant. [EU] Afterload: The tension produced by the heart muscle after contraction. [EU] Agar: A complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae. It is used as a gel in the preparation of solid culture media for microorganisms, as a bulk laxative, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis. [NIH] Agarose: A polysaccharide complex, free of nitrogen and prepared from agar-agar which is produced by certain seaweeds (red algae). It dissolves in warm water to form a viscid solution. [NIH] Age of Onset: The age or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual. [NIH] Ageing: A physiological or morphological change in the life of an organism or its parts, generally irreversible and typically associated with a decline in growth and reproductive vigor. [NIH] Aggravation: An increasing in seriousness or severity; an act or circumstance that intensifies, or makes worse. [EU] Agonist: In anatomy, a prime mover. In pharmacology, a drug that has affinity for and stimulates physiologic activity at cell receptors normally stimulated by naturally occurring substances. [EU] Agrin: A protein component of the synaptic basal lamina. It has been shown to induce clustering of acetylcholine receptors on the surface of muscle fibers and other synaptic molecules in both synapse regeneration and development. [NIH] Air Pressure: The force per unit area that the air exerts on any surface in contact with it. Primarily used for articles pertaining to air pressure within a closed environment. [NIH] Airway: A device for securing unobstructed passage of air into and out of the lungs during general anesthesia. [NIH] Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task. [NIH] Alimentary: Pertaining to food or nutritive material, or to the organs of digestion. [EU] Alkaline: Having the reactions of an alkali. [EU] Alkaloid: A member of a large group of chemicals that are made by plants and have

344 Muscles nitrogen in them. Some alkaloids have been shown to work against cancer. [NIH] Allergen: An antigenic substance capable of producing immediate-type hypersensitivity (allergy). [EU] Alpha Particles: Positively charged particles composed of two protons and two neutrons, i.e., helium nuclei, emitted during disintegration of very heavy isotopes; a beam of alpha particles or an alpha ray has very strong ionizing power, but weak penetrability. [NIH] Alpha-1: A protein with the property of inactivating proteolytic enzymes such as leucocyte collagenase and elastase. [NIH] Alpha-helix: One of the secondary element of protein. [NIH] Alternative medicine: Practices not generally recognized by the medical community as standard or conventional medical approaches and used instead of standard treatments. Alternative medicine includes the taking of dietary supplements, megadose vitamins, and herbal preparations; the drinking of special teas; and practices such as massage therapy, magnet therapy, spiritual healing, and meditation. [NIH] Alternative Splicing: A process whereby multiple protein isoforms are generated from a single gene. Alternative splicing involves the splicing together of nonconsecutive exons during the processing of some, but not all, transcripts of the gene. Thus a particular exon may be connected to any one of several alternative exons to form messenger RNA. The alternative forms produce proteins in which one part is common while the other part is different. [NIH] Alveoli: Tiny air sacs at the end of the bronchioles in the lungs. [NIH] Amblyopia: A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation- induced amblopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. Strabismus and refractive errors may cause this condition. Toxic amblyopia is a disorder of the optic nerve which is associated with alcoholism, tobacco smoking, and other toxins and as an adverse effect of the use of some medications. [NIH] Amino acid: Any organic compound containing an amino (-NH2 and a carboxyl (- COOH) group. The 20 a-amino acids listed in the accompanying table are the amino acids from which proteins are synthesized by formation of peptide bonds during ribosomal translation of messenger RNA; all except glycine, which is not optically active, have the L configuration. Other amino acids occurring in proteins, such as hydroxyproline in collagen, are formed by posttranslational enzymatic modification of amino acids residues in polypeptide chains. There are also several important amino acids, such as the neurotransmitter y-aminobutyric acid, that have no relation to proteins. Abbreviated AA. [EU] Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining protein conformation. [NIH] Ammonia: A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. [NIH] Amplification: The production of additional copies of a chromosomal DNA sequence, found as either intrachromosomal or extrachromosomal DNA. [NIH] Ampulla: A sac-like enlargement of a canal or duct. [NIH] Amputation: Surgery to remove part or all of a limb or appendage. [NIH] Amygdala: Almond-shaped group of basal nuclei anterior to the inferior horn of the lateral ventricle of the brain, within the temporal lobe. The amygdala is part of the limbic system.

Dictionary 345 [NIH] Amyloid: A general term for a variety of different proteins that accumulate as extracellular fibrils of 7-10 nm and have common structural features, including a beta-pleated sheet conformation and the ability to bind such dyes as Congo red and thioflavine (Kandel, Schwartz, and Jessel, Principles of Neural Science, 3rd ed). [NIH] Anabolic: Relating to, characterized by, or promoting anabolism. [EU] Anaerobic: 1. Lacking molecular oxygen. 2. Growing, living, or occurring in the absence of molecular oxygen; pertaining to an anaerobe. [EU] Anaesthesia: Loss of feeling or sensation. Although the term is used for loss of tactile sensibility, or of any of the other senses, it is applied especially to loss of the sensation of pain, as it is induced to permit performance of surgery or other painful procedures. [EU] Anal: Having to do with the anus, which is the posterior opening of the large bowel. [NIH] Anal Fissure: A small tear in the anus that may cause itching, pain, or bleeding. [NIH] Anal Fistula: A channel that develops between the anus and the skin. Most fistulas are the result of an abscess (infection) that spreads to the skin. [NIH] Analgesic: An agent that alleviates pain without causing loss of consciousness. [EU] Analog: In chemistry, a substance that is similar, but not identical, to another. [NIH] Analogous: Resembling or similar in some respects, as in function or appearance, but not in origin or development;. [EU] Anaphylatoxins: The family of peptides C3a, C4a, C5a, and C5a des-arginine produced in the serum during complement activation. They produce smooth muscle contraction, mast cell histamine release, affect platelet aggregation, and act as mediators of the local inflammatory process. The order of anaphylatoxin activity from strongest to weakest is C5a, C3a, C4a, and C5a des-arginine. The latter is the so-called \"classical\" anaphylatoxin but shows no spasmogenic activity though it contains some chemotactic ability. [NIH] Anastomosis: A procedure to connect healthy sections of tubular structures in the body after the diseased portion has been surgically removed. [NIH] Anatomical: Pertaining to anatomy, or to the structure of the organism. [EU] Androgens: A class of sex hormones associated with the development and maintenance of the secondary male sex characteristics, sperm induction, and sexual differentiation. In addition to increasing virility and libido, they also increase nitrogen and water retention and stimulate skeletal growth. [NIH] Anemia: A reduction in the number of circulating erythrocytes or in the quantity of hemoglobin. [NIH] Anesthesia: A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. [NIH] Aneurysm: A sac formed by the dilatation of the wall of an artery, a vein, or the heart. [NIH] Angina: Chest pain that originates in the heart. [NIH] Angiography: Radiography of blood vessels after injection of a contrast medium. [NIH] Angioplasty: Endovascular reconstruction of an artery, which may include the removal of atheromatous plaque and/or the endothelial lining as well as simple dilatation. These are procedures performed by catheterization. When reconstruction of an artery is performed surgically, it is called endarterectomy. [NIH] Angulation: Deviation from the normal long axis, as in a fractured bone healed out of line.

346 Muscles [NIH] Animal model: An animal with a disease either the same as or like a disease in humans. Animal models are used to study the development and progression of diseases and to test new treatments before they are given to humans. Animals with transplanted human cancers or other tissues are called xenograft models. [NIH] Anions: Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis. [NIH] Ankle: That part of the lower limb directly above the foot. [NIH] Ankle Joint: The joint that is formed by the inferior articular and malleolar articular surfaces of the tibia, the malleolar articular surface of the fibula, and the medial malleolar, lateral malleolar, and superior surfaces of the talus. [NIH] Anomalies: Birth defects; abnormalities. [NIH] Anorectal: Pertaining to the anus and rectum or to the junction region between the two. [EU] Anorexia: Lack or loss of appetite for food. Appetite is psychologic, dependent on memory and associations. Anorexia can be brought about by unattractive food, surroundings, or company. [NIH] Anterior chamber: The space in front of the iris and behind the cornea. [NIH] Anterior Cruciate Ligament: A strong ligament of the knee that originates from the posteromedial portion of the lateral condyle of the femur, passes anteriorly and inferiorly between the condyles, and attaches to the depression in front of the intercondylar eminence of the tibia. [NIH] Anterograde: Moving or extending forward; called also antegrade. [EU] Antibacterial: A substance that destroys bacteria or suppresses their growth or reproduction. [EU] Antibiotic: A drug used to treat infections caused by bacteria and other microorganisms. [NIH] Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the antigen that induced their synthesis in cells of the lymphoid series (especially plasma cells), or with an antigen closely related to it. [NIH] Antibody: A type of protein made by certain white blood cells in response to a foreign substance (antigen). Each antibody can bind to only a specific antigen. The purpose of this binding is to help destroy the antigen. Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen. [NIH] Anticoagulant: A drug that helps prevent blood clots from forming. Also called a blood thinner. [NIH] Antigen: Any substance which is capable, under appropriate conditions, of inducing a specific immune response and of reacting with the products of that response, that is, with specific antibody or specifically sensitized T-lymphocytes, or both. Antigens may be soluble substances, such as toxins and foreign proteins, or particulate, such as bacteria and tissue cells; however, only the portion of the protein or polysaccharide molecule known as the antigenic determinant (q.v.) combines with antibody or a specific receptor on a lymphocyte. Abbreviated Ag. [EU] Antigen-Antibody Complex: The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes immune complex diseases. [NIH]

Dictionary 347 Anti-inflammatory: Having to do with reducing inflammation. [NIH] Anti-Inflammatory Agents: Substances that reduce or suppress inflammation. [NIH] Antineoplastic: Inhibiting or preventing the development of neoplasms, checking the maturation and proliferation of malignant cells. [EU] Antioxidant: A substance that prevents damage caused by free radicals. Free radicals are highly reactive chemicals that often contain oxygen. They are produced when molecules are split to give products that have unpaired electrons. This process is called oxidation. [NIH] Antipyretic: An agent that relieves or reduces fever. Called also antifebrile, antithermic and febrifuge. [EU] Anus: The opening of the rectum to the outside of the body. [NIH] Anxiety: Persistent feeling of dread, apprehension, and impending disaster. [NIH] Aorta: The main trunk of the systemic arteries. [NIH] Aortic Valve: The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. [NIH] Aperture: A natural hole of perforation, especially one in a bone. [NIH] Apnea: A transient absence of spontaneous respiration. [NIH] Apolipoproteins: The protein components of lipoproteins which remain after the lipids to which the proteins are bound have been removed. They play an important role in lipid transport and metabolism. [NIH] Apoptosis: One of the two mechanisms by which cell death occurs (the other being the pathological process of necrosis). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA (DNA fragmentation) at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth. [NIH] Applicability: A list of the commodities to which the candidate method can be applied as presented or with minor modifications. [NIH] Approximate: Approximal [EU] Apraxia: Loss of ability to perform purposeful movements, in the absence of paralysis or sensory disturbance, caused by lesions in the cortex. [NIH] Aqueous: Having to do with water. [NIH] Aqueous fluid: Clear, watery fluid that flows between and nourishes the lens and the cornea; secreted by the ciliary processes. [NIH] Aqueous humor: Clear, watery fluid that flows between and nourishes the lens and the cornea; secreted by the ciliary processes. [NIH] Arginase: A ureahydrolase that catalyzes the hydrolysis of arginine or canavanine to yield L-ORNITHINE and urea. Deficiency of this enzyme causes hyperargininemia. EC 3.5.3.1. [NIH] Arginine: An essential amino acid that is physiologically active in the L-form. [NIH] Arterial: Pertaining to an artery or to the arteries. [EU] Arteries: The vessels carrying blood away from the heart. [NIH] Arteriography: A procedure to x-ray arteries. The arteries can be seen because of an injection

348 Muscles of a dye that outlines the vessels on an x-ray. [NIH] Arterioles: The smallest divisions of the arteries located between the muscular arteries and the capillaries. [NIH] Arteriolosclerosis: Sclerosis and thickening of the walls of the smaller arteries (arterioles). Hyaline arteriolosclerosis, in which there is homogeneous pink hyaline thickening of the arteriolar walls, is associated with benign nephrosclerosis. Hyperplastic arteriolosclerosis, in which there is a concentric thickening with progressive narrowing of the lumina may be associated with malignant hypertension, nephrosclerosis, and scleroderma. [EU] Arteriosclerosis: Thickening and loss of elasticity of arterial walls. Atherosclerosis is the most common form of arteriosclerosis and involves lipid deposition and thickening of the intimal cell layers within arteries. Additional forms of arteriosclerosis involve calcification of the media of muscular arteries (Monkeberg medial calcific sclerosis) and thickening of the walls of small arteries or arterioles due to cell proliferation or hyaline deposition (arteriolosclerosis). [NIH] Arteriosus: Circle composed of anastomosing arteries derived from two long posterior ciliary and seven anterior ciliary arteries, located in the ciliary body about the root of the iris. [NIH] Artery: Vessel-carrying blood from the heart to various parts of the body. [NIH] Articular: Of or pertaining to a joint. [EU] Articulation: The relationship of two bodies by means of a moveable joint. [NIH] Artificial Organs: Devices intended to replace non-functioning organs. They may be temporary or permanent. Since they are intended always to function as the natural organs they are replacing, they should be differentiated from prostheses and implants and specific types of prostheses which, though also replacements for body parts, are frequently cosmetic (artificial eye) as well as functional (artificial limbs). [NIH] Asepsis: The prevention of access by infecting organisms to the locus of potential infection. [NIH] Aspartate: A synthetic amino acid. [NIH] Asphyxia: A pathological condition caused by lack of oxygen, manifested in impending or actual cessation of life. [NIH] Aspiration: The act of inhaling. [NIH] Aspirin: A drug that reduces pain, fever, inflammation, and blood clotting. Aspirin belongs to the family of drugs called nonsteroidal anti-inflammatory agents. It is also being studied in cancer prevention. [NIH] Assay: Determination of the amount of a particular constituent of a mixture, or of the biological or pharmacological potency of a drug. [EU] Ataxia: Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharnyx, larnyx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. [NIH] Atrial: Pertaining to an atrium. [EU] Atrioventricular: Pertaining to an atrium of the heart and to a ventricle. [EU] Atrium: A chamber; used in anatomical nomenclature to designate a chamber affording entrance to another structure or organ. Usually used alone to designate an atrium of the

Dictionary 349 heart. [EU] Atrophy: Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. [NIH] Attenuation: Reduction of transmitted sound energy or its electrical equivalent. [NIH] Atypical: Irregular; not conformable to the type; in microbiology, applied specifically to strains of unusual type. [EU] Auditory: Pertaining to the sense of hearing. [EU] Auditory Cortex: Area of the temporal lobe concerned with hearing. [NIH] Autoantibodies: Antibodies that react with self-antigens (autoantigens) of the organism that produced them. [NIH] Autoantigens: Endogenous tissue constituents that have the ability to interact with autoantibodies and cause an immune response. [NIH] Autoimmune disease: A condition in which the body recognizes its own tissues as foreign and directs an immune response against them. [NIH] Autoimmunity: Process whereby the immune system reacts against the body's own tissues. Autoimmunity may produce or be caused by autoimmune diseases. [NIH] Autonomic: Self-controlling; functionally independent. [EU] Autonomic Nervous System: The enteric, parasympathetic, and sympathetic nervous systems taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the central nervous system, especially the hypothalamus and the solitary nucleus, which receive information relayed from visceral afferents; these and related central and sensory structures are sometimes (but not here) considered to be part of the autonomic nervous system itself. [NIH] Autopsy: Postmortem examination of the body. [NIH] Avian: A plasmodial infection in birds. [NIH] Avulsion: The forcible separation, or tearing away, of a part of an organ. [NIH] Axonal: Condition associated with metabolic derangement of the entire neuron and is manifest by degeneration of the distal portion of the nerve fiber. [NIH] Axons: Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body. [NIH] Axotomy: Transection or severing of an axon. This type of denervation is used often in experimental studies on neuronal physiology and neuronal death or survival, toward an understanding of nervous system disease. [NIH] Back Pain: Acute or chronic pain located in the posterior regions of the trunk, including the thoracic, lumbar, sacral, or adjacent regions. [NIH] Bacteria: Unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. [NIH] Bacterial Physiology: Physiological processes and activities of bacteria. [NIH] Bacteriophage: A virus whose host is a bacterial cell; A virus that exclusively infects bacteria. It generally has a protein coat surrounding the genome (DNA or RNA). One of the coliphages most extensively studied is the lambda phage, which is also one of the most important. [NIH]

350 Muscles Bacterium: Microscopic organism which may have a spherical, rod-like, or spiral unicellular or non-cellular body. Bacteria usually reproduce through asexual processes. [NIH] Basal Ganglia: Large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres. [NIH] Basal Ganglia Diseases: Diseases of the basal ganglia including the putamen; globus pallidus; claustrum; amygdala; and caudate nucleus. Dyskinesias (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. Common etiologies include cerebrovascular disease; neurodegenerative diseases; and craniocerebral trauma. [NIH] Base: In chemistry, the nonacid part of a salt; a substance that combines with acids to form salts; a substance that dissociates to give hydroxide ions in aqueous solutions; a substance whose molecule or ion can combine with a proton (hydrogen ion); a substance capable of donating a pair of electrons (to an acid) for the formation of a coordinate covalent bond. [EU] Basement Membrane: Ubiquitous supportive tissue adjacent to epithelium and around smooth and striated muscle cells. This tissue contains intrinsic macromolecular components such as collagen, laminin, and sulfated proteoglycans. As seen by light microscopy one of its subdivisions is the basal (basement) lamina. [NIH] Bed Rest: Confinement of an individual to bed for therapeutic or experimental reasons. [NIH] Bends: The form of aeroembolism that is marked by intense pain in muscles and joints due to formation of gas bubbles in the tissues. [NIH] Benign: Not cancerous; does not invade nearby tissue or spread to other parts of the body. [NIH] Beta-pleated: Particular three-dimensional pattern of amyloidoses. [NIH] Bilateral: Affecting both the right and left side of body. [NIH] Bile: An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts, cholesterol, and electrolytes. It aids digestion of fats in the duodenum. [NIH] Bile Acids: Acids made by the liver that work with bile to break down fats. [NIH] Bile Acids and Salts: Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones. [NIH] Bile duct: A tube through which bile passes in and out of the liver. [NIH] Biliary: Having to do with the liver, bile ducts, and/or gallbladder. [NIH] Bilirubin: A bile pigment that is a degradation product of heme. [NIH] Binding Sites: The reactive parts of a macromolecule that directly participate in its specific combination with another molecule. [NIH] Bioavailability: The degree to which a drug or other substance becomes available to the target tissue after administration. [EU] Biochemical: Relating to biochemistry; characterized by, produced by, or involving chemical reactions in living organisms. [EU] Biogenesis: The origin of life. It includes studies of the potential basis for life in organic compounds but excludes studies of the development of altered forms of life through mutation and natural selection, which is evolution. [NIH]

Dictionary 351 Biological response modifier: BRM. A substance that stimulates the body's response to infection and disease. [NIH] Biological therapy: Treatment to stimulate or restore the ability of the immune system to fight infection and disease. Also used to lessen side effects that may be caused by some cancer treatments. Also known as immunotherapy, biotherapy, or biological response modifier (BRM) therapy. [NIH] Biomechanics: The study of the application of mechanical laws and the action of forces to living structures. [NIH] Biomedical Engineering: Application of principles and practices of engineering science to biomedical research and health care. [NIH] Biopsy: Removal and pathologic examination of specimens in the form of small pieces of tissue from the living body. [NIH] Biotechnology: Body of knowledge related to the use of organisms, cells or cell-derived constituents for the purpose of developing products which are technically, scientifically and clinically useful. Alteration of biologic function at the molecular level (i.e., genetic engineering) is a central focus; laboratory methods used include transfection and cloning technologies, sequence and structure analysis algorithms, computer databases, and gene and protein structure function analysis and prediction. [NIH] Bladder: The organ that stores urine. [NIH] Blepharitis: Inflammation of the eyelids. [NIH] Blepharospasm: Excessive winking; tonic or clonic spasm of the orbicularis oculi muscle. [NIH] Blinking: Brief closing of the eyelids by involuntary normal periodic closing, as a protective measure, or by voluntary action. [NIH] Bloating: Fullness or swelling in the abdomen that often occurs after meals. [NIH] Blood Coagulation: The process of the interaction of blood coagulation factors that results in an insoluble fibrin clot. [NIH] Blood Glucose: Glucose in blood. [NIH] Blood pressure: The pressure of blood against the walls of a blood vessel or heart chamber. Unless there is reference to another location, such as the pulmonary artery or one of the heart chambers, it refers to the pressure in the systemic arteries, as measured, for example, in the forearm. [NIH] Blood vessel: A tube in the body through which blood circulates. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins. [NIH] Blood Volume: Volume of circulating blood. It is the sum of the plasma volume and erythrocyte volume. [NIH] Body Fluids: Liquid components of living organisms. [NIH] Body Mass Index: One of the anthropometric measures of body mass; it has the highest correlation with skinfold thickness or body density. [NIH] Body Regions: Anatomical areas of the body. [NIH] Bolus: A single dose of drug usually injected into a blood vessel over a short period of time. Also called bolus infusion. [NIH] Bolus infusion: A single dose of drug usually injected into a blood vessel over a short period of time. Also called bolus. [NIH] Bone Development: Gross development of bones from fetus to adult. It includes

352 Muscles osteogenesis, which is restricted to formation and development of bone from the undifferentiated cells of the germ layers of the embryo. It does not include osseointegration. [NIH] Bone Marrow: The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells. [NIH] Bone scan: A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner. [NIH] Boron: A trace element with the atomic symbol B, atomic number 5, and atomic weight 10.81. Boron-10, an isotope of boron, is used as a neutron absorber in boron neutron capture therapy. [NIH] Boron Neutron Capture Therapy: A technique for the treatment of neoplasms, especially gliomas and melanomas in which boron-10, an isotope, is introduced into the target cells followed by irradiation with thermal neutrons. [NIH] Bottle Feeding: Use of nursing bottles for feeding. Applies to humans and animals. [NIH] Bowel: The long tube-shaped organ in the abdomen that completes the process of digestion. There is both a small and a large bowel. Also called the intestine. [NIH] Bowel Movement: Body wastes passed through the rectum and anus. [NIH] Brachial: All the nerves from the arm are ripped from the spinal cord. [NIH] Brachial Plexus: The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (C5-C8 and T1), but variations are not uncommon. [NIH] Brachytherapy: A collective term for interstitial, intracavity, and surface radiotherapy. It uses small sealed or partly-sealed sources that may be placed on or near the body surface or within a natural body cavity or implanted directly into the tissues. [NIH] Bradycardia: Excessive slowness in the action of the heart, usually with a heart rate below 60 beats per minute. [NIH] Bradykinin: A nonapeptide messenger that is enzymatically produced from kallidin in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from mast cells during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter. [NIH] Brain Diseases: Pathologic conditions affecting the brain, which is composed of the intracranial components of the central nervous system. This includes (but is not limited to) the cerebral cortex; intracranial white matter; basal ganglia; thalamus; hypothalamus; brain stem; and cerebellum. [NIH] Brain Stem: The part of the brain that connects the cerebral hemispheres with the spinal cord. It consists of the mesencephalon, pons, and medulla oblongata. [NIH] Branch: Most commonly used for branches of nerves, but applied also to other structures. [NIH] Breakdown: A physical, metal, or nervous collapse. [NIH] Bronchi: The larger air passages of the lungs arising from the terminal bifurcation of the

Dictionary 353 trachea. [NIH] Bronchitis: Inflammation (swelling and reddening) of the bronchi. [NIH] Bronchoscopy: Endoscopic examination, therapy or surgery of the bronchi. [NIH] Buccal: Pertaining to or directed toward the cheek. In dental anatomy, used to refer to the buccal surface of a tooth. [EU] Burns: Injuries to tissues caused by contact with heat, steam, chemicals (burns, chemical), electricity (burns, electric), or the like. [NIH] Burns, Electric: Burns produced by contact with electric current or from a sudden discharge of electricity. [NIH] Bursitis: Inflammation of a bursa, occasionally accompanied by a calcific deposit in the underlying supraspinatus tendon; the most common site is the subdeltoid bursa. [EU] Bypass: A surgical procedure in which the doctor creates a new pathway for the flow of body fluids. [NIH] Cachexia: General ill health, malnutrition, and weight loss, usually associated with chronic disease. [NIH] Cadaver: A dead body, usually a human body. [NIH] Calcification: Deposits of calcium in the tissues of the breast. Calcification in the breast can be seen on a mammogram, but cannot be detected by touch. There are two types of breast calcification, macrocalcification and microcalcification. Macrocalcifications are large deposits and are usually not related to cancer. Microcalcifications are specks of calcium that may be found in an area of rapidly dividing cells. Many microcalcifications clustered together may be a sign of cancer. [NIH] Calcineurin: A calcium- and calmodulin-binding protein present in highest concentrations in the central nervous system. Calcineurin is composed of two subunits. A catalytic subunit, calcineurin A, and a regulatory subunit, calcineurin B, with molecular weights of about 60 kD and 19 kD, respectively. Calcineurin has been shown to dephosphorylate a number of phosphoproteins including histones, myosin light chain, and the regulatory subunit of cAMP-dependent protein kinase. It is involved in the regulation of signal transduction and is the target of an important class of immunophilin-immunosuppressive drug complexes in T-lymphocytes that act by inhibiting T-cell activation. EC 3.1.3.-. [NIH] Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. [NIH] Calcium Channels: Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue. [NIH] Calmodulin: A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels. [NIH] Calpain: Cysteine proteinase found in many tissues. Hydrolyzes a variety of endogenous proteins including neuropeptides, cytoskeletal proteins, proteins from smooth muscle,

354 Muscles cardiac muscle, liver, platelets and erythrocytes. Two subclasses having high and low calcium sensitivity are known. Removes Z-discs and M-lines from myofibrils. Activates phosphorylase kinase and cyclic nucleotide-independent protein kinase. [NIH] Cannula: A tube for insertion into a duct or cavity; during insertion its lumen is usually occupied by a trocar. [EU] Capillary: Any one of the minute vessels that connect the arterioles and venules, forming a network in nearly all parts of the body. Their walls act as semipermeable membranes for the interchange of various substances, including fluids, between the blood and tissue fluid; called also vas capillare. [EU] Capsular: Cataract which is initiated by an opacification at the surface of the lens. [NIH] Capsules: Hard or soft soluble containers used for the oral administration of medicine. [NIH] Carbohydrate: An aldehyde or ketone derivative of a polyhydric alcohol, particularly of the pentahydric and hexahydric alcohols. They are so named because the hydrogen and oxygen are usually in the proportion to form water, (CH2O)n. The most important carbohydrates are the starches, sugars, celluloses, and gums. They are classified into mono-, di-, tri-, poly- and heterosaccharides. [EU] Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals. [NIH] Carcinogen: Any substance that causes cancer. [NIH] Carcinogenic: Producing carcinoma. [EU] Carcinoma: Cancer that begins in the skin or in tissues that line or cover internal organs. [NIH] Cardiac: Having to do with the heart. [NIH] Cardiac Output: The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). [NIH] Cardiomyopathy: A general diagnostic term designating primary myocardial disease, often of obscure or unknown etiology. [EU] Cardiomyoplasty: A surgical procedure that involves detaching one end of a back muscle and attaching it to the heart. An electric stimulator causes the muscle to contract to pump blood from the heart. [NIH] Cardiopulmonary: Having to do with the heart and lungs. [NIH] Cardiopulmonary Bypass: Diversion of the flow of blood from the entrance of the right atrium directly to the aorta (or femoral artery) via an oxygenator thus bypassing both the heart and lungs. [NIH] Cardiorespiratory: Relating to the heart and lungs and their function. [EU] Cardiovascular: Having to do with the heart and blood vessels. [NIH] Cardiovascular disease: Any abnormal condition characterized by dysfunction of the heart and blood vessels. CVD includes atherosclerosis (especially coronary heart disease, which can lead to heart attacks), cerebrovascular disease (e.g., stroke), and hypertension (high blood pressure). [NIH] Cardiovascular System: The heart and the blood vessels by which blood is pumped and circulated through the body. [NIH] Carnitine: Constituent of striated muscle and liver. It is used therapeutically to stimulate gastric and pancreatic secretions and in the treatment of hyperlipoproteinemias. [NIH]

Dictionary 355 Carotene: The general name for a group of pigments found in green, yellow, and leafy vegetables, and yellow fruits. The pigments are fat-soluble, unsaturated aliphatic hydrocarbons functioning as provitamins and are converted to vitamin A through enzymatic processes in the intestinal wall. [NIH] Carotid Body: A small cluster of chemoreceptive and supporting cells located near the bifurcation of the internal carotid artery. The carotid body, which is richly supplied with fenestrated capillaries, senses the pH, carbon dioxide, and oxygen concentrations in the blood and plays a crucial role in their homeostatic control. [NIH] Carotid Sinus: The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure. [NIH] Carpal Bones: The eight bones of the wrist: capitate bone, hamate bone, lunate bone (semilunar bone), pisiform bone, scaphoid bone, trapezium bone, trapezoid bone and triquetral bone. [NIH] Carpal Tunnel Syndrome: A median nerve injury inside the carpal tunnel that results in symptoms of pain, numbness, tingling, clumsiness, and a lack of sweating, which can be caused by work with certain hand and wrist postures. [NIH] Case report: A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin). [NIH] Catalyse: To speed up a chemical reaction. [EU] Cataract: An opacity, partial or complete, of one or both eyes, on or in the lens or capsule, especially an opacity impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). [EU] Catheter: A flexible tube used to deliver fluids into or withdraw fluids from the body. [NIH] Catheterization: Use or insertion of a tubular device into a duct, blood vessel, hollow organ, or body cavity for injecting or withdrawing fluids for diagnostic or therapeutic purposes. It differs from intubation in that the tube here is used to restore or maintain patency in obstructions. [NIH] Cathode: An electrode, usually an incandescent filament of tungsten, which emits electrons in an X-ray tube. [NIH] Cations: Postively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis. [NIH] Cauda Equina: The lower part of the spinal cord consisting of the lumbar, sacral, and coccygeal nerve roots. [NIH] Caudal: Denoting a position more toward the cauda, or tail, than some specified point of reference; same as inferior, in human anatomy. [EU] Causal: Pertaining to a cause; directed against a cause. [EU] Cause of Death: Factors which produce cessation of all vital bodily functions. They can be analyzed from an epidemiologic viewpoint. [NIH] Cell: The individual unit that makes up all of the tissues of the body. All living things are made up of one or more cells. [NIH] Cell Adhesion: Adherence of cells to surfaces or to other cells. [NIH] Cell Count: A count of the number of cells of a specific kind, usually measured per unit volume of sample. [NIH]

356 Muscles Cell Death: The termination of the cell's ability to carry out vital functions such as metabolism, growth, reproduction, responsiveness, and adaptability. [NIH] Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function which takes place during the development of the embryo and leads to the formation of specialized cells, tissues, and organs. [NIH] Cell Division: The fission of a cell. [NIH] Cell Lineage: The developmental history of cells as traced from the first division of the original cell or cells in the embryo. [NIH] Cell membrane: Cell membrane = plasma membrane. The structure enveloping a cell, enclosing the cytoplasm, and forming a selective permeability barrier; it consists of lipids, proteins, and some carbohydrates, the lipids thought to form a bilayer in which integral proteins are embedded to varying degrees. [EU] Cell proliferation: An increase in the number of cells as a result of cell growth and cell division. [NIH] Cell Respiration: The metabolic process of all living cells (animal and plant) in which oxygen is used to provide a source of energy for the cell. [NIH] Cell Size: The physical dimensions of a cell. It refers mainly to changes in dimensions correlated with physiological or pathological changes in cells. [NIH] Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability. [NIH] Cell Transplantation: Transference of cells within an individual, between individuals of the same species, or between individuals of different species. [NIH] Cellobiose: A disaccharide consisting of two glucose units in beta (1-4) glycosidic linkage. Obtained from the partial hydrolysis of cellulose. [NIH] Cellulose: A polysaccharide with glucose units linked as in cellobiose. It is the chief constituent of plant fibers, cotton being the purest natural form of the substance. As a raw material, it forms the basis for many derivatives used in chromatography, ion exchange materials, explosives manufacturing, and pharmaceutical preparations. [NIH] Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges. [NIH] Cerebellar: Pertaining to the cerebellum. [EU] Cerebral: Of or pertaining of the cerebrum or the brain. [EU] Cerebral Cortex: The thin layer of gray matter on the surface of the cerebral hemisphere that develops from the telencephalon and folds into gyri. It reaches its highest development in man and is responsible for intellectual faculties and higher mental functions. [NIH] Cerebral Palsy: Refers to a motor disability caused by a brain dysfunction. [NIH] Cerebrospinal: Pertaining to the brain and spinal cord. [EU] Cerebrospinal fluid: CSF. The fluid flowing around the brain and spinal cord. Cerebrospinal fluid is produced in the ventricles in the brain. [NIH] Cerebrovascular: Pertaining to the blood vessels of the cerebrum, or brain. [EU] Cerebrum: The largest part of the brain. It is divided into two hemispheres, or halves, called the cerebral hemispheres. The cerebrum controls muscle functions of the body and also controls speech, emotions, reading, writing, and learning. [NIH] Cervical: Relating to the neck, or to the neck of any organ or structure. Cervical lymph

Dictionary 357 nodes are located in the neck; cervical cancer refers to cancer of the uterine cervix, which is the lower, narrow end (the \"neck\") of the uterus. [NIH] Cervical Plexus: A network of nerve fibers originating in the upper four cervical spinal cord segments. The cervical plexus distributes cutaneous nerves to parts of the neck, shoulders, and back of the head, and motor fibers to muscles of the cervical spinal column, infrahyoid muscles, and the diaphragm. [NIH] Cervix: The lower, narrow end of the uterus that forms a canal between the uterus and vagina. [NIH] Character: In current usage, approximately equivalent to personality. The sum of the relatively fixed personality traits and habitual modes of response of an individual. [NIH] Chemoreceptor: A receptor adapted for excitation by chemical substances, e.g., olfactory and gustatory receptors, or a sense organ, as the carotid body or the aortic (supracardial) bodies, which is sensitive to chemical changes in the blood stream, especially reduced oxygen content, and reflexly increases both respiration and blood pressure. [EU] Chemotactic Factors: Chemical substances that attract or repel cells or organisms. The concept denotes especially those factors released as a result of tissue injury, invasion, or immunologic activity, that attract leukocytes, macrophages, or other cells to the site of infection or insult. [NIH] Chemotherapy: Treatment with anticancer drugs. [NIH] Child Development: The continuous sequential physiological and psychological maturing of the child from birth up to but not including adolescence. It includes healthy responses to situations, but does not include growth in stature or size (= growth). [NIH] Chimeras: Organism that contains a mixture of genetically different cells. [NIH] Chin: The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve. [NIH] Chiropractic: A system of treating bodily disorders by manipulation of the spine and other parts, based on the belief that the cause is the abnormal functioning of a nerve. [NIH] Chlorine: A greenish-yellow, diatomic gas that is a member of the halogen family of elements. It has the atomic symbol Cl, atomic number 17, and atomic weight 70.906. It is a powerful irritant that can cause fatal pulmonary edema. Chlorine is used in manufacturing, as a reagent in synthetic chemistry, for water purification, and in the production of chlorinated lime, which is used in fabric bleaching. [NIH] Chloroprene: Toxic, possibly carcinogenic, monomer of neoprene, a synthetic rubber; causes damage to skin, lungs, CNS, kidneys, liver, blood cells and fetuses. Synonym: 2- chlorobutadiene. [NIH] Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. [NIH] Cholesterol Esters: Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis. [NIH] Choline: A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism. [NIH]

358 Muscles Cholinergic: Resembling acetylcholine in pharmacological action; stimulated by or releasing acetylcholine or a related compound. [EU] Chondrocytes: Polymorphic cells that form cartilage. [NIH] Chordae Tendineae: The tendinous cords that connect each cusp of the two atrioventricular valves to appropriate papillary muscles in the heart ventricles, preventing the valves from reversing themselves when the ventricles contract. [NIH] Choroid: The thin, highly vascular membrane covering most of the posterior of the eye between the retina and sclera. [NIH] Chromatin: The material of chromosomes. It is a complex of DNA, histones, and nonhistone proteins (chromosomal proteins, non-histone) found within the nucleus of a cell. [NIH] Chromium: A trace element that plays a role in glucose metabolism. It has the atomic symbol Cr, atomic number 24, and atomic weight 52. According to the Fourth Annual Report on Carcinogens (NTP85-002,1985), chromium and some of its compounds have been listed as known carcinogens. [NIH] Chromosomal: Pertaining to chromosomes. [EU] Chromosome: Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes. [NIH] Chronic: A disease or condition that persists or progresses over a long period of time. [NIH] Chronic Disease: Disease or ailment of long duration. [NIH] Chronic Obstructive Pulmonary Disease: Collective term for chronic bronchitis and emphysema. [NIH] Chronic renal: Slow and progressive loss of kidney function over several years, often resulting in end-stage renal disease. People with end-stage renal disease need dialysis or transplantation to replace the work of the kidneys. [NIH] Chylomicrons: A class of lipoproteins that carry dietary cholesterol and triglycerides from the small intestines to the tissues. [NIH] Ciliary: Inflammation or infection of the glands of the margins of the eyelids. [NIH] Ciliary Body: A ring of tissue extending from the scleral spur to the ora serrata of the retina. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion. [NIH] Ciliary processes: The extensions or projections of the ciliary body that secrete aqueous humor. [NIH] CIS: Cancer Information Service. The CIS is the National Cancer Institute's link to the public, interpreting and explaining research findings in a clear and understandable manner, and providing personalized responses to specific questions about cancer. Access the CIS by calling 1-800-4-CANCER, or by using the Web site at http://cis.nci.nih.gov. [NIH] Clavicle: A long bone of the shoulder girdle. [NIH] Clear cell carcinoma: A rare type of tumor of the female genital tract in which the inside of the cells looks clear when viewed under a microscope. [NIH] Clinical Medicine: The study and practice of medicine by direct examination of the patient. [NIH] Clinical trial: A research study that tests how well new medical treatments or other interventions work in people. Each study is designed to test new methods of screening, prevention, diagnosis, or treatment of a disease. [NIH] Clone: The term \"clone\" has acquired a new meaning. It is applied specifically to the bits of

Dictionary 359 inserted foreign DNA in the hybrid molecules of the population. Each inserted segment originally resided in the DNA of a complex genome amid millions of other DNA segment. [NIH] Clonic: Pertaining to or of the nature of clonus. [EU] Cloning: The production of a number of genetically identical individuals; in genetic engineering, a process for the efficient replication of a great number of identical DNA molecules. [NIH] Cochlea: The part of the internal ear that is concerned with hearing. It forms the anterior part of the labyrinth, is conical, and is placed almost horizontally anterior to the vestibule. [NIH] Cochlear: Of or pertaining to the cochlea. [EU] Cochlear Implants: Electronic devices implanted beneath the skin with electrodes to the cochlear nerve to create sound sensation in persons with sensorineural deafness. [NIH] Cochlear Nerve: The cochlear part of the 8th cranial nerve (vestibulocochlear nerve). The cochlear nerve fibers originate from neurons of the spiral ganglion and project peripherally to cochlear hair cells and centrally to the cochlear nuclei (cochlear nucleus) of the brain stem. They mediate the sense of hearing. [NIH] Cochlear Nucleus: The brain stem nucleus that receives the central input from the cochlear nerve. The cochlear nucleus is located lateral and dorsolateral to the inferior cerebellar peduncles and is functionally divided into dorsal and ventral parts. It is tonotopically organized, performs the first stage of central auditory processing, and projects (directly or indirectly) to higher auditory areas including the superior olivary nuclei, the medial geniculi, the inferior colliculi, and the auditory cortex. [NIH] Coenzyme: An organic nonprotein molecule, frequently a phosphorylated derivative of a water-soluble vitamin, that binds with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme). [EU] Cofactor: A substance, microorganism or environmental factor that activates or enhances the action of another entity such as a disease-causing agent. [NIH] Cognitive restructuring: A method of identifying and replacing fear-promoting, irrational beliefs with more realistic and functional ones. [NIH] Colectomy: An operation to remove the colon. An open colectomy is the removal of the colon through a surgical incision made in the wall of the abdomen. Laparoscopic-assisted colectomy uses a thin, lighted tube attached to a video camera. It allows the surgeon to remove the colon without a large incision. [NIH] Collagen: A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin, connective tissue, and the organic substance of bones and teeth. Different forms of collagen are produced in the body but all consist of three alpha-polypeptide chains arranged in a triple helix. Collagen is differentiated from other fibrous proteins, such as elastin, by the content of proline, hydroxyproline, and hydroxylysine; by the absence of tryptophan; and particularly by the high content of polar groups which are responsible for its swelling properties. [NIH] Collapse: 1. A state of extreme prostration and depression, with failure of circulation. 2. Abnormal falling in of the walls of any part of organ. [EU] Colloidal: Of the nature of a colloid. [EU] Colon: The long, coiled, tubelike organ that removes water from digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus. [NIH]

360 Muscles Colostomy: An opening into the colon from the outside of the body. A colostomy provides a new path for waste material to leave the body after part of the colon has been removed. [NIH] Combination Therapy: Association of 3 drugs to treat AIDS (AZT + DDC or DDI + protease inhibitor). [NIH] Common Bile Duct: The largest biliary duct. It is formed by the junction of the cystic duct and the hepatic duct. [NIH] Complement: A term originally used to refer to the heat-labile factor in serum that causes immune cytolysis, the lysis of antibody-coated cells, and now referring to the entire functionally related system comprising at least 20 distinct serum proteins that is the effector not only of immune cytolysis but also of other biologic functions. Complement activation occurs by two different sequences, the classic and alternative pathways. The proteins of the classic pathway are termed 'components of complement' and are designated by the symbols C1 through C9. C1 is a calcium-dependent complex of three distinct proteins C1q, C1r and C1s. The proteins of the alternative pathway (collectively referred to as the properdin system) and complement regulatory proteins are known by semisystematic or trivial names. Fragments resulting from proteolytic cleavage of complement proteins are designated with lower-case letter suffixes, e.g., C3a. Inactivated fragments may be designated with the suffix 'i', e.g. C3bi. Activated components or complexes with biological activity are designated by a bar over the symbol e.g. C1 or C4b,2a. The classic pathway is activated by the binding of C1 to classic pathway activators, primarily antigen-antibody complexes containing IgM, IgG1, IgG3; C1q binds to a single IgM molecule or two adjacent IgG molecules. The alternative pathway can be activated by IgA immune complexes and also by nonimmunologic materials including bacterial endotoxins, microbial polysaccharides, and cell walls. Activation of the classic pathway triggers an enzymatic cascade involving C1, C4, C2 and C3; activation of the alternative pathway triggers a cascade involving C3 and factors B, D and P. Both result in the cleavage of C5 and the formation of the membrane attack complex. Complement activation also results in the formation of many biologically active complement fragments that act as anaphylatoxins, opsonins, or chemotactic factors. [EU] Complementary and alternative medicine: CAM. Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices are not considered standard medical approaches. CAM includes dietary supplements, megadose vitamins, herbal preparations, special teas, massage therapy, magnet therapy, spiritual healing, and meditation. [NIH] Complementary medicine: Practices not generally recognized by the medical community as standard or conventional medical approaches and used to enhance or complement the standard treatments. Complementary medicine includes the taking of dietary supplements, megadose vitamins, and herbal preparations; the drinking of special teas; and practices such as massage therapy, magnet therapy, spiritual healing, and meditation. [NIH] Complementation: The production of a wild-type phenotype when two different mutations are combined in a diploid or a heterokaryon and tested in trans-configuration. [NIH] Computational Biology: A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories applicable to molecular biology and areas of computer-based techniques for solving biological problems including manipulation of models and datasets. [NIH] Computed tomography: CT scan. A series of detailed pictures of areas inside the body, taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized tomography and computerized axial tomography (CAT) scan. [NIH]

Dictionary 361 Computer Systems: Systems composed of a computer or computers, peripheral equipment, such as disks, printers, and terminals, and telecommunications capabilities. [NIH] Computerized tomography: A series of detailed pictures of areas inside the body, taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized axial tomography (CAT) scan and computed tomography (CT scan). [NIH] Concentric: Having a common center of curvature or symmetry. [NIH] Concomitant: Accompanying; accessory; joined with another. [EU] Conduction: The transfer of sound waves, heat, nervous impulses, or electricity. [EU] Cone: One of the special retinal receptor elements which are presumed to be primarily concerned with perception of light and color stimuli when the eye is adapted to light. [NIH] Congestion: Excessive or abnormal accumulation of blood in a part. [EU] Conjugated: Acting or operating as if joined; simultaneous. [EU] Conjugation: 1. The act of joining together or the state of being conjugated. 2. A sexual process seen in bacteria, ciliate protozoa, and certain fungi in which nuclear material is exchanged during the temporary fusion of two cells (conjugants). In bacterial genetics a form of sexual reproduction in which a donor bacterium (male) contributes some, or all, of its DNA (in the form of a replicated set) to a recipient (female) which then incorporates differing genetic information into its own chromosome by recombination and passes the recombined set on to its progeny by replication. In ciliate protozoa, two conjugants of separate mating types exchange micronuclear material and then separate, each now being a fertilized cell. In certain fungi, the process involves fusion of two gametes, resulting in union of their nuclei and formation of a zygote. 3. In chemistry, the joining together of two compounds to produce another compound, such as the combination of a toxic product with some substance in the body to form a detoxified product, which is then eliminated. [EU] Conjunctiva: The mucous membrane that lines the inner surface of the eyelids and the anterior part of the sclera. [NIH] Connective Tissue: Tissue that supports and binds other tissues. It consists of connective tissue cells embedded in a large amount of extracellular matrix. [NIH] Connective Tissue: Tissue that supports and binds other tissues. It consists of connective tissue cells embedded in a large amount of extracellular matrix. [NIH] Connective Tissue Cells: A group of cells that includes fibroblasts, cartilage cells, adipocytes, smooth muscle cells, and bone cells. [NIH] Consciousness: Sense of awareness of self and of the environment. [NIH] Constipation: Infrequent or difficult evacuation of feces. [NIH] Constitutional: 1. Affecting the whole constitution of the body; not local. 2. Pertaining to the constitution. [EU] Constriction: The act of constricting. [NIH] Consultation: A deliberation between two or more physicians concerning the diagnosis and the proper method of treatment in a case. [NIH] Consumption: Pulmonary tuberculosis. [NIH] Contamination: The soiling or pollution by inferior material, as by the introduction of organisms into a wound, or sewage into a stream. [EU] Continence: The ability to hold in a bowel movement or urine. [NIH] Contractile Proteins: Proteins which participate in contractile processes. They include

362 Muscles muscle proteins as well as those found in other cells and tissues. In the latter, these proteins participate in localized contractile events in the cytoplasm, in motile activity, and in cell aggregation phenomena. [NIH] Contractility: Capacity for becoming short in response to a suitable stimulus. [EU] Contracture: A condition of fixed high resistance to passive stretch of a muscle, resulting from fibrosis of the tissues supporting the muscles or the joints, or from disorders of the muscle fibres. [EU] Contraindications: Any factor or sign that it is unwise to pursue a certain kind of action or treatment, e. g. giving a general anesthetic to a person with pneumonia. [NIH] Contralateral: Having to do with the opposite side of the body. [NIH] Contrast medium: A substance that is introduced into or around a structure and, because of the difference in absorption of x-rays by the contrast medium and the surrounding tissues, allows radiographic visualization of the structure. [EU] Control group: In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works. [NIH] Conus: A large, circular, white patch around the optic disk due to the exposing of the sclera as a result of degenerative change or congenital abnormality in the choroid and retina. [NIH] Coordination: Muscular or motor regulation or the harmonious cooperation of muscles or groups of muscles, in a complex action or series of actions. [NIH] Cornea: The transparent part of the eye that covers the iris and the pupil and allows light to enter the inside. [NIH] Corneum: The superficial layer of the epidermis containing keratinized cells. [NIH] Coronary: Encircling in the manner of a crown; a term applied to vessels; nerves, ligaments, etc. The term usually denotes the arteries that supply the heart muscle and, by extension, a pathologic involvement of them. [EU] Coronary Artery Bypass: Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion. [NIH] Coronary heart disease: A type of heart disease caused by narrowing of the coronary arteries that feed the heart, which needs a constant supply of oxygen and nutrients carried by the blood in the coronary arteries. When the coronary arteries become narrowed or clogged by fat and cholesterol deposits and cannot supply enough blood to the heart, CHD results. [NIH] Coronary Thrombosis: Presence of a thrombus in a coronary artery, often causing a myocardial infarction. [NIH] Corpus: The body of the uterus. [NIH] Corpus Luteum: The yellow glandular mass formed in the ovary by an ovarian follicle that has ruptured and discharged its ovum. [NIH] Cortex: The outer layer of an organ or other body structure, as distinguished from the internal substance. [EU] Cortical: Pertaining to or of the nature of a cortex or bark. [EU] Corticosteroid: Any of the steroids elaborated by the adrenal cortex (excluding the sex hormones of adrenal origin) in response to the release of corticotrophin (adrenocorticotropic hormone) by the pituitary gland, to any of the synthetic equivalents of these steroids, or to angiotensin II. They are divided, according to their predominant biological activity, into

Dictionary 363 three major groups: glucocorticoids, chiefly influencing carbohydrate, fat, and protein metabolism; mineralocorticoids, affecting the regulation of electrolyte and water balance; and C19 androgens. Some corticosteroids exhibit both types of activity in varying degrees, and others exert only one type of effect. The corticosteroids are used clinically for hormonal replacement therapy, for suppression of ACTH secretion by the anterior pituitary, as antineoplastic, antiallergic, and anti-inflammatory agents, and to suppress the immune response. Called also adrenocortical hormone and corticoid. [EU] Cortisone: A natural steroid hormone produced in the adrenal gland. It can also be made in the laboratory. Cortisone reduces swelling and can suppress immune responses. [NIH] Cranial: Pertaining to the cranium, or to the anterior (in animals) or superior (in humans) end of the body. [EU] Craniosynostoses: Premature closure of one or more sutures of the skull. [NIH] Creatine: An amino acid that occurs in vertebrate tissues and in urine. In muscle tissue, creatine generally occurs as phosphocreatine. Creatine is excreted as creatinine in the urine. [NIH] Creatine Kinase: A transferase that catalyzes formation of phosphocreatine from ATP + creatine. The reaction stores ATP energy as phosphocreatine. Three cytoplasmic isoenzymes have been identified in human tissues: MM from skeletal muscle, MB from myocardial tissue, and BB from nervous tissue as well as a mitochondrial isoenzyme. Macro-creatine kinase refers to creatine kinase complexed with other serum proteins. EC 2.7.3.2. [NIH] Creatinine: A compound that is excreted from the body in urine. Creatinine levels are measured to monitor kidney function. [NIH] Criterion: A standard by which something may be judged. [EU] Critical Illness: A disease or state in which death is possible or imminent. [NIH] Crossing-over: The exchange of corresponding segments between chromatids of homologous chromosomes during meiosia, forming a chiasma. [NIH] Cryotherapy: Any method that uses cold temperature to treat disease. [NIH] Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond. [NIH] Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as agar or gelatin. [NIH] Curare: Plant extracts from several species, including Strychnos toxifera, S. castelnaei, S. crevauxii, and Chondodendron tomentosum, that produce paralysis of skeletal muscle and are used adjunctively with general anesthesia. These extracts are toxic and must be used with the administration of artificial respiration. [NIH] Curative: Tending to overcome disease and promote recovery. [EU] Curcumin: A dye obtained from tumeric, the powdered root of Curcuma longa Linn. It is used in the preparation of curcuma paper and the detection of boron. Curcumin appears to possess a spectrum of pharmacological properties, due primarily to its inhibitory effects on metabolic enzymes. [NIH] Cutaneous: Having to do with the skin. [NIH] Cyclic: Pertaining to or occurring in a cycle or cycles; the term is applied to chemical compounds that contain a ring of atoms in the nucleus. [EU]

364 Muscles Cyclin: Molecule that regulates the cell cycle. [NIH] Cystectomy: Used for excision of the urinary bladder. [NIH] Cystic Duct: The tube that carries bile from the gallbladder into the common bile duct and the small intestine. [NIH] Cytogenetics: A branch of genetics which deals with the cytological and molecular behavior of genes and chromosomes during cell division. [NIH] Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non- leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner. [NIH] Cytomegalovirus: A genus of the family Herpesviridae, subfamily Betaherpesvirinae, infecting the salivary glands, liver, spleen, lungs, eyes, and other organs, in which they produce characteristically enlarged cells with intranuclear inclusions. Infection with Cytomegalovirus is also seen as an opportunistic infection in AIDS. [NIH] Cytoplasm: The protoplasm of a cell exclusive of that of the nucleus; it consists of a continuous aqueous solution (cytosol) and the organelles and inclusions suspended in it (phaneroplasm), and is the site of most of the chemical activities of the cell. [EU] Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm. [NIH] Cytotoxic: Cell-killing. [NIH] Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data. [NIH] Deamination: The removal of an amino group (NH2) from a chemical compound. [NIH] Defecation: The normal process of elimination of fecal material from the rectum. [NIH] Degenerative: Undergoing degeneration : tending to degenerate; having the character of or involving degeneration; causing or tending to cause degeneration. [EU] Deglutition: The process or the act of swallowing. [NIH] Dehydration: The condition that results from excessive loss of body water. [NIH] Dehydroepiandrosterone: DHEA. A substance that is being studied as a cancer prevention drug. It belongs to the family of drugs called steroids. [NIH] Deletion: A genetic rearrangement through loss of segments of DNA (chromosomes), bringing sequences, which are normally separated, into close proximity. [NIH] Delivery of Health Care: The concept concerned with all aspects of providing and distributing health services to a patient population. [NIH] Dementia: An acquired organic mental disorder with loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning. The dysfunction is multifaceted and involves memory, behavior, personality, judgment, attention, spatial relations, language, abstract thought, and other executive functions. The intellectual decline is usually progressive, and initially spares the level of consciousness. [NIH] Denaturation: Rupture of the hydrogen bonds by heating a DNA solution and then cooling it rapidly causes the two complementary strands to separate. [NIH] Dendrites: Extensions of the nerve cell body. They are short and branched and receive stimuli from other neurons. [NIH] Dendritic: 1. Branched like a tree. 2. Pertaining to or possessing dendrites. [EU]

Dictionary 365 Density: The logarithm to the base 10 of the opacity of an exposed and processed film. [NIH] Dental Care: The total of dental diagnostic, preventive, and restorative services provided to meet the needs of a patient (from Illustrated Dictionary of Dentistry, 1982). [NIH] Dentition: The teeth in the dental arch; ordinarily used to designate the natural teeth in position in their alveoli. [EU] Deoxyribonucleic: A polymer of subunits called deoxyribonucleotides which is the primary genetic material of a cell, the material equivalent to genetic information. [NIH] Deoxyribonucleic acid: A polymer of subunits called deoxyribonucleotides which is the primary genetic material of a cell, the material equivalent to genetic information. [NIH] Deoxyribonucleotides: A purine or pyrimidine base bonded to a deoxyribose containing a bond to a phosphate group. [NIH] Depolarization: The process or act of neutralizing polarity. In neurophysiology, the reversal of the resting potential in excitable cell membranes when stimulated, i.e., the tendency of the cell membrane potential to become positive with respect to the potential outside the cell. [EU] Deprivation: Loss or absence of parts, organs, powers, or things that are needed. [EU] Depth Perception: Perception of three-dimensionality. [NIH] DES: Diethylstilbestrol. A synthetic hormone that was prescribed from the early 1940s until 1971 to help women with complications of pregnancy. DES has been linked to an increased risk of clear cell carcinoma of the vagina in daughters of women who used DES. DES may also increase the risk of breast cancer in women who used DES. [NIH] Desensitization: The prevention or reduction of immediate hypersensitivity reactions by administration of graded doses of allergen; called also hyposensitization and immunotherapy. [EU] Dexamethasone: (11 beta,16 alpha)-9-Fluoro-11,17,21-trihydroxy-16-methylpregna-1,4- diene-3,20-dione. An anti-inflammatory glucocorticoid used either in the free alcohol or esterified form in treatment of conditions that respond generally to cortisone. [NIH] Dexterity: Ability to move the hands easily and skillfully. [NIH] Diabetes Mellitus: A heterogeneous group of disorders that share glucose intolerance in common. [NIH] Diagnostic procedure: A method used to identify a disease. [NIH] Dialyzer: A part of the hemodialysis machine. (See hemodialysis under dialysis.) The dialyzer has two sections separated by a membrane. One section holds dialysate. The other holds the patient's blood. [NIH] Diaphragm: The musculofibrous partition that separates the thoracic cavity from the abdominal cavity. Contraction of the diaphragm increases the volume of the thoracic cavity aiding inspiration. [NIH] Diarrhea: Passage of excessively liquid or excessively frequent stools. [NIH] Diastole: Period of relaxation of the heart, especially the ventricles. [NIH] Diastolic: Of or pertaining to the diastole. [EU] Diathermy: The induction of local hyperthermia by either short radio waves or high- frequency sound waves. [NIH] Diencephalon: The paired caudal parts of the prosencephalon from which the thalamus, hypothalamus, epithalamus, and subthalamus are derived. [NIH] Digestion: The process of breakdown of food for metabolism and use by the body. [NIH]

366 Muscles Digestive system: The organs that take in food and turn it into products that the body can use to stay healthy. Waste products the body cannot use leave the body through bowel movements. The digestive system includes the salivary glands, mouth, esophagus, stomach, liver, pancreas, gallbladder, small and large intestines, and rectum. [NIH] Digestive tract: The organs through which food passes when food is eaten. These organs are the mouth, esophagus, stomach, small and large intestines, and rectum. [NIH] Digitalis: A genus of toxic herbaceous Eurasian plants of the Scrophulaceae which yield cardiotonic glycosides. The most useful are Digitalis lanata and D. purpurea. [NIH] Dilatation: The act of dilating. [NIH] Dilatation, Pathologic: The condition of an anatomical structure's being dilated beyond normal dimensions. [NIH] Dilation: A process by which the pupil is temporarily enlarged with special eye drops (mydriatic); allows the eye care specialist to better view the inside of the eye. [NIH] Dilator: A device used to stretch or enlarge an opening. [NIH] Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer. [NIH] Diploid: Having two sets of chromosomes. [NIH] Direct: 1. Straight; in a straight line. 2. Performed immediately and without the intervention of subsidiary means. [EU] Discrete: Made up of separate parts or characterized by lesions which do not become blended; not running together; separate. [NIH] Disparity: Failure of the two retinal images of an object to fall on corresponding retinal points. [NIH] Dissection: Cutting up of an organism for study. [NIH] Dissociation: 1. The act of separating or state of being separated. 2. The separation of a molecule into two or more fragments (atoms, molecules, ions, or free radicals) produced by the absorption of light or thermal energy or by solvation. 3. In psychology, a defense mechanism in which a group of mental processes are segregated from the rest of a person's mental activity in order to avoid emotional distress, as in the dissociative disorders (q.v.), or in which an idea or object is segregated from its emotional significance; in the first sense it is roughly equivalent to splitting, in the second, to isolation. 4. A defect of mental integration in which one or more groups of mental processes become separated off from normal consciousness and, thus separated, function as a unitary whole. [EU] Dissociative Disorders: Sudden temporary alterations in the normally integrative functions of consciousness. [NIH] Distal: Remote; farther from any point of reference; opposed to proximal. In dentistry, used to designate a position on the dental arch farther from the median line of the jaw. [EU] Dominance: In genetics, the full phenotypic expression of a gene in both heterozygotes and homozygotes. [EU] Dorsal: 1. Pertaining to the back or to any dorsum. 2. Denoting a position more toward the back surface than some other object of reference; same as posterior in human anatomy; superior in the anatomy of quadrupeds. [EU] Dosage Forms: Completed forms of the pharmaceutical preparation in which prescribed doses of medication are included. They are designed to resist action by gastric fluids, prevent vomiting and nausea, reduce or alleviate the undesirable taste and smells associated with oral administration, achieve a high concentration of drug at target site, or produce a

Dictionary 367 delayed or long-acting drug effect. They include capsules, liniments, ointments, pharmaceutical solutions, powders, tablets, etc. [NIH] Drive: A state of internal activity of an organism that is a necessary condition before a given stimulus will elicit a class of responses; e.g., a certain level of hunger (drive) must be present before food will elicit an eating response. [NIH] Drug Delivery Systems: Systems of administering drugs through controlled delivery so that an optimum amount reaches the target site. Drug delivery systems encompass the carrier, route, and target. [NIH] Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug. [NIH] Duct: A tube through which body fluids pass. [NIH] Duodenum: The first part of the small intestine. [NIH] Dyes: Chemical substances that are used to stain and color other materials. The coloring may or may not be permanent. Dyes can also be used as therapeutic agents and test reagents in medicine and scientific research. [NIH] Dynamometer: An instrument for measuring the force of muscular contraction. [NIH] Dysarthria: Imperfect articulation of speech due to disturbances of muscular control which result from damage to the central or peripheral nervous system. [EU] Dysphagia: Difficulty in swallowing. [EU] Dysphonia: Difficulty or pain in speaking; impairment of the voice. [NIH] Dysplasia: Cells that look abnormal under a microscope but are not cancer. [NIH] Dystonia: Disordered tonicity of muscle. [EU] Dystrophic: Pertaining to toxic habitats low in nutrients. [NIH] Dystrophin: A muscle protein localized in surface membranes which is the product of the Duchenne/Becker muscular dystrophy gene. Individuals with Duchenne muscular dystrophy usually lack dystrophin completely while those with Becker muscular dystrophy have dystrophin of an altered size. It shares features with other cytoskeletal proteins such as spectrin and alpha-actinin but the precise function of dystrophin is not clear. One possible role might be to preserve the integrity and alignment of the plasma membrane to the myofibrils during muscle contraction and relaxation. MW 400 kDa. [NIH] Dystrophy: Any disorder arising from defective or faulty nutrition, especially the muscular dystrophies. [EU] Eardrum: A thin, tense membrane forming the greater part of the outer wall of the tympanic cavity and separating it from the external auditory meatus; it constitutes the boundary between the external and middle ear. [NIH] Ecchymosis: Extravasation of blood into the skin, resulting in a nonelevated, rounded or irregular, blue or purplish patch, larger than a petechia. [NIH] Ectoderm: The outer of the three germ layers of the embryo. [NIH] Ectopic: Pertaining to or characterized by ectopia. [EU] Edema: Excessive amount of watery fluid accumulated in the intercellular spaces, most commonly present in subcutaneous tissue. [NIH] Effector: It is often an enzyme that converts an inactive precursor molecule into an active second messenger. [NIH] Efferent: Nerve fibers which conduct impulses from the central nervous system to muscles and glands. [NIH]

368 Muscles Efficacy: The extent to which a specific intervention, procedure, regimen, or service produces a beneficial result under ideal conditions. Ideally, the determination of efficacy is based on the results of a randomized control trial. [NIH] Ejection fraction: A measure of ventricular contractility, equal to normally 65 8 per cent; lower values indicate ventricular dysfunction. [EU] Elastic: Susceptible of resisting and recovering from stretching, compression or distortion applied by a force. [EU] Elasticity: Resistance and recovery from distortion of shape. [NIH] Elastin: The protein that gives flexibility to tissues. [NIH] Elective: Subject to the choice or decision of the patient or physician; applied to procedures that are advantageous to the patient but not urgent. [EU] Electrode: Component of the pacing system which is at the distal end of the lead. It is the interface with living cardiac tissue across which the stimulus is transmitted. [NIH] Electrodiagnosis: Diagnosis of disease states by recording the spontaneous electrical activity of tissues or organs or by the response to stimulation of electrically excitable tissue. [NIH] Electrolysis: Destruction by passage of a galvanic electric current, as in disintegration of a chemical compound in solution. [NIH] Electrolyte: A substance that dissociates into ions when fused or in solution, and thus becomes capable of conducting electricity; an ionic solute. [EU] Electromagnetic Fields: Fields representing the joint interplay of electric and magnetic forces. [NIH] Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes. [NIH] Electrophoresis: An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current. [NIH] Electrophysiological: Pertaining to electrophysiology, that is a branch of physiology that is concerned with the electric phenomena associated with living bodies and involved in their functional activity. [EU] Elementary Particles: Individual components of atoms, usually subatomic; subnuclear particles are usually detected only when the atomic nucleus decays and then only transiently, as most of them are unstable, often yielding pure energy without substance, i.e., radiation. [NIH] Embolus: Bit of foreign matter which enters the blood stream at one point and is carried until it is lodged or impacted in an artery and obstructs it. It may be a blood clot, an air bubble, fat or other tissue, or clumps of bacteria. [NIH] Embryo: The prenatal stage of mammalian development characterized by rapid morphological changes and the differentiation of basic structures. [NIH] Emphysema: A pathological accumulation of air in tissues or organs. [NIH] Empirical: A treatment based on an assumed diagnosis, prior to receiving confirmatory laboratory test results. [NIH] Emulsion: A preparation of one liquid distributed in small globules throughout the body of a second liquid. The dispersed liquid is the discontinuous phase, and the dispersion medium is the continuous phase. When oil is the dispersed liquid and an aqueous solution is the continuous phase, it is known as an oil-in-water emulsion, whereas when water or aqueous solution is the dispersed phase and oil or oleaginous substance is the continuous

Dictionary 369 phase, it is known as a water-in-oil emulsion. Pharmaceutical emulsions for which official standards have been promulgated include cod liver oil emulsion, cod liver oil emulsion with malt, liquid petrolatum emulsion, and phenolphthalein in liquid petrolatum emulsion. [EU] Enamel: A very hard whitish substance which covers the dentine of the anatomical crown of a tooth. [NIH] Encapsulated: Confined to a specific, localized area and surrounded by a thin layer of tissue. [NIH] Encephalitis: Inflammation of the brain due to infection, autoimmune processes, toxins, and other conditions. Viral infections (see encephalitis, viral) are a relatively frequent cause of this condition. [NIH] Encephalocele: Cerebral tissue herniation through a congenital or acquired defect in the skull. The majority of congenital encephaloceles occur in the occipital or frontal regions. Clinical features include a protuberant mass that may be pulsatile. The quantity and location of protruding neural tissue determines the type and degree of neurologic deficit. Visual defects, psychomotor developmental delay, and persistent motor deficits frequently occur. [NIH] Encephalomyelitis: A general term indicating inflammation of the brain and spinal cord, often used to indicate an infectious process, but also applicable to a variety of autoimmune and toxic-metabolic conditions. There is significant overlap regarding the usage of this term and encephalitis in the literature. [NIH] Endarterectomy: Surgical excision, performed under general anesthesia, of the atheromatous tunica intima of an artery. When reconstruction of an artery is performed as an endovascular procedure through a catheter, it is called atherectomy. [NIH] Endemic: Present or usually prevalent in a population or geographical area at all times; said of a disease or agent. Called also endemial. [EU] Endocrine System: The system of glands that release their secretions (hormones) directly into the circulatory system. In addition to the endocrine glands, included are the chromaffin system and the neurosecretory systems. [NIH] Endocrinology: A subspecialty of internal medicine concerned with the metabolism, physiology, and disorders of the endocrine system. [NIH] Endogenous: Produced inside an organism or cell. The opposite is external (exogenous) production. [NIH] Endometrium: The layer of tissue that lines the uterus. [NIH] Endoscope: A thin, lighted tube used to look at tissues inside the body. [NIH] Endoscopic: A technique where a lateral-view endoscope is passed orally to the duodenum for visualization of the ampulla of Vater. [NIH] Endothelial cell: The main type of cell found in the inside lining of blood vessels, lymph vessels, and the heart. [NIH] Endothelium: A layer of epithelium that lines the heart, blood vessels (endothelium, vascular), lymph vessels (endothelium, lymphatic), and the serous cavities of the body. [NIH] Endothelium, Lymphatic: Unbroken cellular lining (intima) of the lymph vessels (e.g., the high endothelial lymphatic venules). It is more permeable than vascular endothelium, lacking selective absorption and functioning mainly to remove plasma proteins that have filtered through the capillaries into the tissue spaces. [NIH] Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components from interstitium to lumen; this function has been most intensively studied in the blood

370 Muscles capillaries. [NIH] Endothelium-derived: Small molecule that diffuses to the adjacent muscle layer and relaxes it. [NIH] Endotoxin: Toxin from cell walls of bacteria. [NIH] End-stage renal: Total chronic kidney failure. When the kidneys fail, the body retains fluid and harmful wastes build up. A person with ESRD needs treatment to replace the work of the failed kidneys. [NIH] Energetic: Exhibiting energy : strenuous; operating with force, vigour, or effect. [EU] Energy balance: Energy is the capacity of a body or a physical system for doing work. Energy balance is the state in which the total energy intake equals total energy needs. [NIH] Enhancer: Transcriptional element in the virus genome. [NIH] Environmental Exposure: The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals. [NIH] Environmental Health: The science of controlling or modifying those conditions, influences, or forces surrounding man which relate to promoting, establishing, and maintaining health. [NIH] Enzymatic: Phase where enzyme cuts the precursor protein. [NIH] Enzyme: A protein that speeds up chemical reactions in the body. [NIH] Epidemic: Occurring suddenly in numbers clearly in excess of normal expectancy; said especially of infectious diseases but applied also to any disease, injury, or other health- related event occurring in such outbreaks. [EU] Epidermis: Nonvascular layer of the skin. It is made up, from within outward, of five layers: 1) basal layer (stratum basale epidermidis); 2) spinous layer (stratum spinosum epidermidis); 3) granular layer (stratum granulosum epidermidis); 4) clear layer (stratum lucidum epidermidis); and 5) horny layer (stratum corneum epidermidis). [NIH] Epidural: The space between the wall of the spinal canal and the covering of the spinal cord. An epidural injection is given into this space. [NIH] Epigastric: Having to do with the upper middle area of the abdomen. [NIH] Epiglottis: Thin leaf-shaped cartilage, covered with mucous membrane, at the root of the tongue, which folds back over the entrance to the larynx, covering it, during the act of swallowing. [NIH] Epinephrine: The active sympathomimetic hormone from the adrenal medulla in most species. It stimulates both the alpha- and beta- adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. It is used in asthma and cardiac failure and to delay absorption of local anesthetics. [NIH] Episiotomy: An incision of the posterior vaginal wall and a portion of the pudenda which enlarges the vaginal introitus to facilitate delivery and prevent lacerations. [NIH] Epithelial: Refers to the cells that line the internal and external surfaces of the body. [NIH] Epithelial Cells: Cells that line the inner and outer surfaces of the body. [NIH] Epithelium: One or more layers of epithelial cells, supported by the basal lamina, which covers the inner or outer surfaces of the body. [NIH] Erectile: The inability to get or maintain an erection for satisfactory sexual intercourse. Also called impotence. [NIH]

Dictionary 371 Erection: The condition of being made rigid and elevated; as erectile tissue when filled with blood. [EU] Ergonomics: Study of the relationships between man and machines; adjusting the design of machines to the need and capacities of man; study of the effect of machines on man's behavior. [NIH] Erythrina: A genus of leguminous shrubs or trees, mainly tropical, yielding certain alkaloids, lectins, and other useful compounds. [NIH] Erythrocyte Volume: Volume of circulating erythrocytes. It is usually measured by radioisotope dilution technique. [NIH] Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing hemoglobin whose function is to transport oxygen. [NIH] Esophageal: Having to do with the esophagus, the muscular tube through which food passes from the throat to the stomach. [NIH] Esophagus: The muscular tube through which food passes from the throat to the stomach. [NIH] Esotropia: A form of ocular misalignment characterized by an excessive convergence of the visual axes, resulting in a \"cross-eye\" appearance. An example of this condition occurs when paralysis of the lateral rectus muscle causes an abnormal inward deviation of one eye on attempted gaze. [NIH] Essential Tremor: A rhythmic, involuntary, purposeless, oscillating movement resulting from the alternate contraction and relaxation of opposing groups of muscles. [NIH] Estradiol: The most potent mammalian estrogenic hormone. It is produced in the ovary, placenta, testis, and possibly the adrenal cortex. [NIH] Estrogen: One of the two female sex hormones. [NIH] Estrone: 3-Hydroxyestra-1,3,5(10)-trien-17-one. A metabolite of estradiol but possessing less biological activity. It is found in the urine of pregnant women and mares, in the human placenta, and in the urine of bulls and stallions. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), estrone may reasonably be anticipated to be a carcinogen (Merck, 11th ed). [NIH] Ethnic Groups: A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships. [NIH] Eukaryotic Cells: Cells of the higher organisms, containing a true nucleus bounded by a nuclear membrane. [NIH] Evacuation: An emptying, as of the bowels. [EU] Evoke: The electric response recorded from the cerebral cortex after stimulation of a peripheral sense organ. [NIH] Evoked Potentials: The electric response evoked in the central nervous system by stimulation of sensory receptors or some point on the sensory pathway leading from the receptor to the cortex. The evoked stimulus can be auditory, somatosensory, or visual, although other modalities have been reported. Event-related potentials is sometimes used synonymously with evoked potentials but is often associated with the execution of a motor, cognitive, or psychophysiological task, as well as with the response to a stimulus. [NIH] Excitability: Property of a cardiac cell whereby, when the cell is depolarized to a critical level (called threshold), the membrane becomes permeable and a regenerative inward current causes an action potential. [NIH] Excitation: An act of irritation or stimulation or of responding to a stimulus; the addition of

372 Muscles energy, as the excitation of a molecule by absorption of photons. [EU] Excitatory: When cortical neurons are excited, their output increases and each new input they receive while they are still excited raises their output markedly. [NIH] Excitatory Amino Acid Agonists: Drugs that bind to and activate excitatory amino acid receptors. [NIH] Exercise Test: Controlled physical activity, more strenuous than at rest, which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used. The intensity of exercise is often graded, using criteria such as rate of work done, oxygen consumption, and heart rate. Physiological data obtained from an exercise test may be used for diagnosis, prognosis, and evaluation of disease severity, and to evaluate therapy. Data may also be used in prescribing exercise by determining a person's exercise capacity. [NIH] Exercise Therapy: Motion of the body or its parts to relieve symptoms or to improve function, leading to physical fitness, but not physical education and training. [NIH] Exercise Tolerance: The exercise capacity of an individual as measured by endurance (maximal exercise duration and/or maximal attained work load) during an exercise test. [NIH] Exhaustion: The feeling of weariness of mind and body. [NIH] Exocrine: Secreting outwardly, via a duct. [EU] Exocytosis: Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the cell membrane. [NIH] Exogenous: Developed or originating outside the organism, as exogenous disease. [EU] Exons: Coding regions of messenger RNA included in the genetic transcript which survive the processing of RNA in cell nuclei to become part of a spliced messenger of structural RNA in the cytoplasm. They include joining and diversity exons of immunoglobulin genes. [NIH] Exotropia: A form of ocular misalignment where the visual axes diverge inappropriately. For example, medial rectus muscle weakness may produce this condition as the affected eye will deviate laterally upon attempted forward gaze. An exotropia occurs due to the relatively unopposed force exerted on the eye by the lateral rectus muscle, which pulls the eye in an outward direction. [NIH] Expiration: The act of breathing out, or expelling air from the lungs. [EU] Expiratory: The volume of air which leaves the breathing organs in each expiration. [NIH] Extensor: A muscle whose contraction tends to straighten a limb; the antagonist of a flexor. [NIH] External-beam radiation: Radiation therapy that uses a machine to aim high-energy rays at the cancer. Also called external radiation. [NIH] Extracellular: Outside a cell or cells. [EU] Extracellular Matrix: A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere. [NIH] Extracellular Space: Interstitial space between cells, occupied by fluid as well as amorphous and fibrous substances. [NIH] Extraction: The process or act of pulling or drawing out. [EU]

Dictionary 373 Extraocular: External to or outside of the eye. [NIH] Extremity: A limb; an arm or leg (membrum); sometimes applied specifically to a hand or foot. [EU] Eye Infections: Infection, moderate to severe, caused by bacteria, fungi, or viruses, which occurs either on the external surface of the eye or intraocularly with probable inflammation, visual impairment, or blindness. [NIH] Eye Movements: Voluntary or reflex-controlled movements of the eye. [NIH] Eye socket: One of the two cavities in the skull which contains an eyeball. Each eye is located in a bony socket or orbit. [NIH] Facial: Of or pertaining to the face. [EU] Facial Expression: Observable changes of expression in the face in response to emotional stimuli. [NIH] Facial Nerve: The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear. [NIH] Facial Paralysis: Severe or complete loss of facial muscle motor function. This condition may result from central or peripheral lesions. Damage to CNS motor pathways from the cerebral cortex to the facial nuclei in the pons leads to facial weakness that generally spares the forehead muscles. Facial nerve diseases generally results in generalized hemifacial weakness. Neuromuscular junction diseases and muscular diseases may also cause facial paralysis or paresis. [NIH] Fallopian tube: The oviduct, a muscular tube about 10 cm long, lying in the upper border of the broad ligament. [NIH] Family Planning: Programs or services designed to assist the family in controlling reproduction by either improving or diminishing fertility. [NIH] Fat: Total lipids including phospholipids. [NIH] Fatigue: The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. [NIH] Fatty acids: A major component of fats that are used by the body for energy and tissue development. [NIH] Feces: The excrement discharged from the intestines, consisting of bacteria, cells exfoliated from the intestines, secretions, chiefly of the liver, and a small amount of food residue. [EU] Femoral: Pertaining to the femur, or to the thigh. [EU] Femoral Artery: The main artery of the thigh, a continuation of the external iliac artery. [NIH] Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee. [NIH] Fetal Development: Morphologic and physiologic growth and development of the mammalian embryo or fetus. [NIH] Fetus: The developing offspring from 7 to 8 weeks after conception until birth. [NIH] Fibrin: A protein derived from fibrinogen in the presence of thrombin, which forms part of the blood clot. [NIH] Fibrinogen: Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-

374 Muscles identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides A and B, the proteolytic action of other enzymes yields different fibrinogen degradation products. [NIH] Fibroblast Growth Factor: Peptide isolated from the pituitary gland and from the brain. It is a potent mitogen which stimulates growth of a variety of mesodermal cells including chondrocytes, granulosa, and endothelial cells. The peptide may be active in wound healing and animal limb regeneration. [NIH] Fibrosis: Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. [NIH] Fibula: The bone of the lower leg lateral to and smaller than the tibia. In proportion to its length, it is the most slender of the long bones. [NIH] Filtration: The passage of a liquid through a filter, accomplished by gravity, pressure, or vacuum (suction). [EU] Fine-needle aspiration: The removal of tissue or fluid with a needle for examination under a microscope. Also called needle biopsy. [NIH] Finite Element Analysis: A computer based method of simulating or analyzing the behavior of structures or components. [NIH] Fistulas: An abnormal passage from one hollow structure of the body to another, or from a hollow structure to the surface, formed by an abscess, disease process, incomplete closure of a wound, or by a congenital anomaly. [NIH] Fixation: 1. The act or operation of holding, suturing, or fastening in a fixed position. 2. The condition of being held in a fixed position. 3. In psychiatry, a term with two related but distinct meanings : (1) arrest of development at a particular stage, which like regression (return to an earlier stage), if temporary is a normal reaction to setbacks and difficulties but if protracted or frequent is a cause of developmental failures and emotional problems, and (2) a close and suffocating attachment to another person, especially a childhood figure, such as one's mother or father. Both meanings are derived from psychoanalytic theory and refer to 'fixation' of libidinal energy either in a specific erogenous zone, hence fixation at the oral, anal, or phallic stage, or in a specific object, hence mother or father fixation. 4. The use of a fixative (q.v.) to preserve histological or cytological specimens. 5. In chemistry, the process whereby a substance is removed from the gaseous or solution phase and localized, as in carbon dioxide fixation or nitrogen fixation. 6. In ophthalmology, direction of the gaze so that the visual image of the object falls on the fovea centralis. 7. In film processing, the chemical removal of all undeveloped salts of the film emulsion, leaving only the developed silver to form a permanent image. [EU] Flatus: Gas passed through the rectum. [NIH] Flexion: In gynaecology, a displacement of the uterus in which the organ is bent so far forward or backward that an acute angle forms between the fundus and the cervix. [EU] Flexor: Muscles which flex a joint. [NIH] Fluorescence: The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis. [NIH] Fold: A plication or doubling of various parts of the body. [NIH] Follicular Phase: The period of the menstrual cycle that begins with menstruation and ends with ovulation. [NIH]

Dictionary 375 Foramen: A natural hole of perforation, especially one in a bone. [NIH] Forearm: The part between the elbow and the wrist. [NIH] Fossa: A cavity, depression, or pit. [NIH] Fovea: The central part of the macula that provides the sharpest vision. [NIH] Fractionation: Dividing the total dose of radiation therapy into several smaller, equal doses delivered over a period of several days. [NIH] Free Radicals: Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated. [NIH] Friction: Surface resistance to the relative motion of one body against the rubbing, sliding, rolling, or flowing of another with which it is in contact. [NIH] Frontal Lobe: The anterior part of the cerebral hemisphere. [NIH] Fructose: A type of sugar found in many fruits and vegetables and in honey. Fructose is used to sweeten some diet foods. It is considered a nutritive sweetener because it has calories. [NIH] Functional Disorders: Disorders such as irritable bowel syndrome. These conditions result from poor nerve and muscle function. Symptoms such as gas, pain, constipation, and diarrhea come back again and again, but there are no signs of disease or damage. Emotional stress can trigger symptoms. Also called motility disorders. [NIH] Fundus: The larger part of a hollow organ that is farthest away from the organ's opening. The bladder, gallbladder, stomach, uterus, eye, and cavity of the middle ear all have a fundus. [NIH] Fungi: A kingdom of eukaryotic, heterotrophic organisms that live as saprobes or parasites, including mushrooms, yeasts, smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi refer to those that grow as multicelluar colonies (mushrooms and molds). [NIH] Gait: Manner or style of walking. [NIH] Gallbladder: The pear-shaped organ that sits below the liver. Bile is concentrated and stored in the gallbladder. [NIH] Gallstones: The solid masses or stones made of cholesterol or bilirubin that form in the gallbladder or bile ducts. [NIH] Gamma Rays: Very powerful and penetrating, high-energy electromagnetic radiation of shorter wavelength than that of x-rays. They are emitted by a decaying nucleus, usually between 0.01 and 10 MeV. They are also called nuclear x-rays. [NIH] Ganglia: Clusters of multipolar neurons surrounded by a capsule of loosely organized connective tissue located outside the central nervous system. [NIH] Ganglion: 1. A knot, or knotlike mass. 2. A general term for a group of nerve cell bodies located outside the central nervous system; occasionally applied to certain nuclear groups within the brain or spinal cord, e.g. basal ganglia. 3. A benign cystic tumour occurring on a aponeurosis or tendon, as in the wrist or dorsum of the foot; it consists of a thin fibrous capsule enclosing a clear mucinous fluid. [EU] Gas: Air that comes from normal breakdown of food. The gases are passed out of the body through the rectum (flatus) or the mouth (burp). [NIH] Gas exchange: Primary function of the lungs; transfer of oxygen from inhaled air into the

376 Muscles blood and of carbon dioxide from the blood into the lungs. [NIH] Gastric: Having to do with the stomach. [NIH] Gastric Emptying: The evacuation of food from the stomach into the duodenum. [NIH] Gastrin: A hormone released after eating. Gastrin causes the stomach to produce more acid. [NIH] Gastrointestinal: Refers to the stomach and intestines. [NIH] Gastrointestinal tract: The stomach and intestines. [NIH] Gastroparesis: Nerve or muscle damage in the stomach. Causes slow digestion and emptying, vomiting, nausea, or bloating. Also called delayed gastric emptying. [NIH] Gelatin: A product formed from skin, white connective tissue, or bone collagen. It is used as a protein food adjuvant, plasma substitute, hemostatic, suspending agent in pharmaceutical preparations, and in the manufacturing of capsules and suppositories. [NIH] Gelsolin: A 90-kD protein produced by macrophages that severs actin filaments and forms a cap on the newly exposed filament end. Gelsolin is activated by calcium ions and participates in the assembly and disassembly of actin, thereby increasing the motility of some cells. [NIH] Gene: The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein. [NIH] Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus. [NIH] Gene Expression: The phenotypic manifestation of a gene or genes by the processes of gene action. [NIH] Gene Expression Profiling: The determination of the pattern of genes expressed i.e., transcribed, under specific circumstances or in a specific cell. [NIH] Gene Therapy: The introduction of new genes into cells for the purpose of treating disease by restoring or adding gene expression. Techniques include insertion of retroviral vectors, transfection, homologous recombination, and injection of new genes into the nuclei of single cell embryos. The entire gene therapy process may consist of multiple steps. The new genes may be introduced into proliferating cells in vivo (e.g., bone marrow) or in vitro (e.g., fibroblast cultures) and the modified cells transferred to the site where the gene expression is required. Gene therapy may be particularly useful for treating enzyme deficiency diseases, hemoglobinopathies, and leukemias and may also prove useful in restoring drug sensitivity, particularly for leukemia. [NIH] Generator: Any system incorporating a fixed parent radionuclide from which is produced a daughter radionuclide which is to be removed by elution or by any other method and used in a radiopharmaceutical. [NIH] Genetic Engineering: Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc. [NIH] Genetics: The biological science that deals with the phenomena and mechanisms of heredity. [NIH] Genitals: Sex organs, including the penis and testicles in men and the vagina and vulva in women. [NIH]

Dictionary 377 Genotype: The genetic constitution of the individual; the characterization of the genes. [NIH] Germ Cells: The reproductive cells in multicellular organisms. [NIH] Germ Layers: The three layers of cells comprising the early embryo. [NIH] Gestation: The period of development of the young in viviparous animals, from the time of fertilization of the ovum until birth. [EU] Gestures: Movement of a part of the body for the purpose of communication. [NIH] Ginseng: An araliaceous genus of plants that contains a number of pharmacologically active agents used as stimulants, sedatives, and tonics, especially in traditional medicine. [NIH] Gland: An organ that produces and releases one or more substances for use in the body. Some glands produce fluids that affect tissues or organs. Others produce hormones or participate in blood production. [NIH] Glomerular: Pertaining to or of the nature of a glomerulus, especially a renal glomerulus. [EU] Glossopharyngeal Nerve: The 9th cranial nerve. The glossopharyngeal nerve is a mixed motor and sensory nerve; it conveys somatic and autonomic efferents as well as general, special, and visceral afferents. Among the connections are motor fibers to the stylopharyngeus muscle, parasympathetic fibers to the parotid glands, general and taste afferents from the posterior third of the tongue, the nasopharynx, and the palate, and afferents from baroreceptors and chemoreceptors of the carotid sinus. [NIH] Glucocorticoid: A compound that belongs to the family of compounds called corticosteroids (steroids). Glucocorticoids affect metabolism and have anti-inflammatory and immunosuppressive effects. They may be naturally produced (hormones) or synthetic (drugs). [NIH] Glucose: D-Glucose. A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. [NIH] Glucose Intolerance: A pathological state in which the fasting plasma glucose level is less than 140 mg per deciliter and the 30-, 60-, or 90-minute plasma glucose concentration following a glucose tolerance test exceeds 200 mg per deciliter. This condition is seen frequently in diabetes mellitus but also occurs with other diseases. [NIH] Glucuronic Acid: Derivatives of uronic acid found throughout the plant and animal kingdoms. They detoxify drugs and toxins by conjugating with them to form glucuronides in the liver which are more water-soluble metabolites that can be easily eliminated from the body. [NIH] Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid (glutamate) is the most common excitatory neurotransmitter in the central nervous system. [NIH] Glutamine: A non-essential amino acid present abundantly throught the body and is involved in many metabolic processes. It is synthesized from glutamic acid and ammonia. It is the principal carrier of nitrogen in the body and is an important energy source for many cells. [NIH] Glutathione Peroxidase: An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC 1.11.1.9. [NIH] Glycerol: A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, and sweetening agent. [NIH]

378 Muscles Glycerophospholipids: Derivatives of phosphatidic acid in which the hydrophobic regions are composed of two fatty acids and a polar alcohol is joined to the C-3 position of glycerol through a phosphodiester bond. They are named according to their polar head groups, such as phosphatidylcholine and phosphatidylethanolamine. [NIH] Glycine: A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter. [NIH] Glycogen: A sugar stored in the liver and muscles. It releases glucose into the blood when cells need it for energy. Glycogen is the chief source of stored fuel in the body. [NIH] Glycogen Synthase: An enzyme that catalyzes the transfer of D-glucose from UDPglucose into 1,4-alpha-D-glucosyl chains. EC 2.4.1.11. [NIH] Glycols: A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights. [NIH] Glycoprotein: A protein that has sugar molecules attached to it. [NIH] Glycoside: Any compound that contains a carbohydrate molecule (sugar), particularly any such natural product in plants, convertible, by hydrolytic cleavage, into sugar and a nonsugar component (aglycone), and named specifically for the sugar contained, as glucoside (glucose), pentoside (pentose), fructoside (fructose) etc. [EU] Glycosidic: Formed by elimination of water between the anomeric hydroxyl of one sugar and a hydroxyl of another sugar molecule. [NIH] Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction. [NIH] Goats: Any of numerous agile, hollow-horned ruminants of the genus Capra, closely related to the sheep. [NIH] Gonad: A sex organ, such as an ovary or a testicle, which produces the gametes in most multicellular animals. [NIH] Gonadal: Pertaining to a gonad. [EU] Governing Board: The group in which legal authority is vested for the control of health- related institutions and organizations. [NIH] Gp120: 120-kD HIV envelope glycoprotein which is involved in the binding of the virus to its membrane receptor, the CD4 molecule, found on the surface of certain cells in the body. [NIH] Grade: The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer. [NIH] Graft: Healthy skin, bone, or other tissue taken from one part of the body and used to replace diseased or injured tissue removed from another part of the body. [NIH] Grafting: The operation of transfer of tissue from one site to another. [NIH] Granule: A small pill made from sucrose. [EU] Granulocytes: Leukocytes with abundant granules in the cytoplasm. They are divided into three groups: neutrophils, eosinophils, and basophils. [NIH] Gravidity: Pregnancy; the condition of being pregnant, without regard to the outcome. [EU] Gravis: Eruption of watery blisters on the skin among those handling animals and animal products. [NIH]

Dictionary 379 Groin: The external junctural region between the lower part of the abdomen and the thigh. [NIH] Growth: The progressive development of a living being or part of an organism from its earliest stage to maturity. [NIH] Growth factors: Substances made by the body that function to regulate cell division and cell survival. Some growth factors are also produced in the laboratory and used in biological therapy. [NIH] Guanylate Cyclase: An enzyme that catalyzes the conversion of GTP to 3',5'-cyclic GMP and pyrophosphate. It also acts on ITP and dGTP. (From Enzyme Nomenclature, 1992) EC 4.6.1.2. [NIH] Hair Cells: Mechanoreceptors located in the organ of Corti that are sensitive to auditory stimuli and in the vestibular apparatus that are sensitive to movement of the head. In each case the accessory sensory structures are arranged so that appropriate stimuli cause movement of the hair-like projections (stereocilia and kinocilia) which relay the information centrally in the nervous system. [NIH] Hair follicles: Shafts or openings on the surface of the skin through which hair grows. [NIH] Hallucinogen: A hallucination-producing drug, a category of drugs producing this effect. The user of a hallucinogenic drug is almost invariably aware that what he is seeing are hallucinations. [NIH] Hammer: The largest of the three ossicles of the ear. [NIH] Happiness: Highly pleasant emotion characterized by outward manifestations of gratification; joy. [NIH] Haptens: Small antigenic determinants capable of eliciting an immune response only when coupled to a carrier. Haptens bind to antibodies but by themselves cannot elicit an antibody response. [NIH] Health Care Costs: The actual costs of providing services related to the delivery of health care, including the costs of procedures, therapies, and medications. It is differentiated from health expenditures, which refers to the amount of money paid for the services, and from fees, which refers to the amount charged, regardless of cost. [NIH] Health Expenditures: The amounts spent by individuals, groups, nations, or private or public organizations for total health care and/or its various components. These amounts may or may not be equivalent to the actual costs (health care costs) and may or may not be shared among the patient, insurers, and/or employers. [NIH] Health Promotion: Encouraging consumer behaviors most likely to optimize health potentials (physical and psychosocial) through health information, preventive programs, and access to medical care. [NIH] Heart attack: A seizure of weak or abnormal functioning of the heart. [NIH] Heart failure: Loss of pumping ability by the heart, often accompanied by fatigue, breathlessness, and excess fluid accumulation in body tissues. [NIH] Helix-loop-helix: Regulatory protein of cell cycle. [NIH] Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins. [NIH] Hemiparesis: The weakness or paralysis affecting one side of the body. [NIH] Hemodialysis: The use of a machine to clean wastes from the blood after the kidneys have failed. The blood travels through tubes to a dialyzer, which removes wastes and extra fluid. The cleaned blood then flows through another set of tubes back into the body. [NIH]

380 Muscles Hemodynamics: The movements of the blood and the forces involved in systemic or regional blood circulation. [NIH] Hemoglobin: One of the fractions of glycosylated hemoglobin A1c. Glycosylated hemoglobin is formed when linkages of glucose and related monosaccharides bind to hemoglobin A and its concentration represents the average blood glucose level over the previous several weeks. HbA1c levels are used as a measure of long-term control of plasma glucose (normal, 4 to 6 percent). In controlled diabetes mellitus, the concentration of glycosylated hemoglobin A is within the normal range, but in uncontrolled cases the level may be 3 to 4 times the normal conentration. Generally, complications are substantially lower among patients with Hb levels of 7 percent or less than in patients with HbA1c levels of 9 percent or more. [NIH] Hemoglobinopathies: A group of inherited disorders characterized by structural alterations within the hemoglobin molecule. [NIH] Hemoglobinuria: The presence of free hemoglobin in the urine. [NIH] Hemophilia: Refers to a group of hereditary disorders in which affected individuals fail to make enough of certain proteins needed to form blood clots. [NIH] Hemorrhage: Bleeding or escape of blood from a vessel. [NIH] Hemorrhoids: Varicosities of the hemorrhoidal venous plexuses. [NIH] Heparin: Heparinic acid. A highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from six to twenty thousand. Heparin occurs in and is obtained from liver, lung, mast cells, etc., of vertebrates. Its function is unknown, but it is used to prevent blood clotting in vivo and vitro, in the form of many different salts. [NIH] Hepatic: Refers to the liver. [NIH] Hepatitis: Inflammation of the liver and liver disease involving degenerative or necrotic alterations of hepatocytes. [NIH] Hepatitis A: Hepatitis caused by hepatovirus. It can be transmitted through fecal contamination of food or water. [NIH] Hepatocytes: The main structural component of the liver. They are specialized epithelial cells that are organized into interconnected plates called lobules. [NIH] Hepatovirus: A genus of Picornaviridae causing infectious hepatitis naturally in humans and experimentally in other primates. It is transmitted through fecal contamination of food or water. [NIH] Hereditary: Of, relating to, or denoting factors that can be transmitted genetically from one generation to another. [NIH] Heredity: 1. The genetic transmission of a particular quality or trait from parent to offspring. 2. The genetic constitution of an individual. [EU] Hernia: Protrusion of a loop or knuckle of an organ or tissue through an abnormal opening. [NIH] Herniated: Protrusion of a degenerated or fragmented intervertebral disc into the intervertebral foramen compressing the nerve root. [NIH] Heterogeneity: The property of one or more samples or populations which implies that they are not identical in respect of some or all of their parameters, e. g. heterogeneity of variance. [NIH] Heterotropia: One in which the angle of squint remains relatively unaltered on conjugate movement of the eyes. [NIH]

Dictionary 381 Heterozygotes: Having unlike alleles at one or more corresponding loci on homologous chromosomes. [NIH] Hippocampus: A curved elevation of gray matter extending the entire length of the floor of the temporal horn of the lateral ventricle (Dorland, 28th ed). The hippocampus, subiculum, and dentate gyrus constitute the hippocampal formation. Sometimes authors include the entorhinal cortex in the hippocampal formation. [NIH] Histology: The study of tissues and cells under a microscope. [NIH] Homeostasis: The processes whereby the internal environment of an organism tends to remain balanced and stable. [NIH] Homogeneous: Consisting of or composed of similar elements or ingredients; of a uniform quality throughout. [EU] Homologous: Corresponding in structure, position, origin, etc., as (a) the feathers of a bird and the scales of a fish, (b) antigen and its specific antibody, (c) allelic chromosomes. [EU] Hormonal: Pertaining to or of the nature of a hormone. [EU] Hormone: A substance in the body that regulates certain organs. Hormones such as gastrin help in breaking down food. Some hormones come from cells in the stomach and small intestine. [NIH] Horny layer: The superficial layer of the epidermis containing keratinized cells. [NIH] Host: Any animal that receives a transplanted graft. [NIH] Human Engineering: The science of designing, building or equipping mechanical devices or artificial environments to the anthropometric, physiological, or psychological requirements of the people who will use them. [NIH] Humeral: 1. Of, relating to, or situated in the region of the humerus: brachial. 2. Of or belonging to the shoulder. 3. Of, relating to, or being any of several body parts that are analogous in structure, function, or location to the humerus or shoulder. [EU] Humoral: Of, relating to, proceeding from, or involving a bodily humour - now often used of endocrine factors as opposed to neural or somatic. [EU] Humour: 1. A normal functioning fluid or semifluid of the body (as the blood, lymph or bile) especially of vertebrates. 2. A secretion that is itself an excitant of activity (as certain hormones). [EU] Hybrid: Cross fertilization between two varieties or, more usually, two species of vines, see also crossing. [NIH] Hydrogen: The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight 1. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are protons. Besides the common H1 isotope, hydrogen exists as the stable isotope deuterium and the unstable, radioactive isotope tritium. [NIH] Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials. [NIH] Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water. [NIH] Hydrophobic: Not readily absorbing water, or being adversely affected by water, as a hydrophobic colloid. [EU] Hydroxides: Inorganic compounds that contain the OH- group. [NIH]

382 Muscles Hydroxyl Radical: The univalent radical OH that is present in hydroxides, alcohols, phenols, glycols. [NIH] Hydroxylation: Hydroxylate, to introduce hydroxyl into (a compound or radical) usually by replacement of hydrogen. [EU] Hydroxylysine: A hydroxylated derivative of the amino acid lysine that is present in certain collagens. [NIH] Hydroxyproline: A hydroxylated form of the imino acid proline. A deficiency in ascorbic acid can result in impaired hydroxyproline formation. [NIH] Hyperalgesia: Excessive sensitiveness or sensibility to pain. [EU] Hypercapnia: A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood. [NIH] Hypercholesterolemia: Abnormally high levels of cholesterol in the blood. [NIH] Hyperglycemia: Abnormally high blood sugar. [NIH] Hyperplasia: An increase in the number of cells in a tissue or organ, not due to tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. [NIH] Hypersensitivity: Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen. [NIH] Hypertension: Persistently high arterial blood pressure. Currently accepted threshold levels are 140 mm Hg systolic and 90 mm Hg diastolic pressure. [NIH] Hyperthermia: A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs. [NIH] Hyperthyroidism: Excessive functional activity of the thyroid gland. [NIH] Hypertonia: Or hypertony n, pl. hypertonias or hypertonies : hypertonicity. n. Pathology: increased rigidity, tension and spasticity of the muscles. [EU] Hypertrophy: General increase in bulk of a part or organ, not due to tumor formation, nor to an increase in the number of cells. [NIH] Hyperventilation: A pulmonary ventilation rate faster than is metabolically necessary for the exchange of gases. It is the result of an increased frequency of breathing, an increased tidal volume, or a combination of both. It causes an excess intake of oxygen and the blowing off of carbon dioxide. [NIH] Hypnotic: A drug that acts to induce sleep. [EU] Hypochlorous Acid: HClO. An oxyacid of chlorine containing monovalent chlorine that acts as an oxidizing or reducing agent. [NIH] Hypoglossal Nerve: The 12th cranial nerve. The hypoglossal nerve originates in the hypoglossal nucleus of the medulla and supplies motor innervation to all of the muscles of the tongue except the palatoglossus (which is supplied by the vagus). This nerve also contains proprioceptive afferents from the tongue muscles. [NIH] Hypoglycemia: Abnormally low blood sugar [NIH] Hypothalamic: Of or involving the hypothalamus. [EU] Hypothalamus: Ventral part of the diencephalon extending from the region of the optic chiasm to the caudal border of the mammillary bodies and forming the inferior and lateral walls of the third ventricle. [NIH] Hypotonia: A condition of diminished tone of the skeletal muscles; diminished resistance of

Dictionary 383 muscles to passive stretching. [EU] Hypoventilation: A reduction in the amount of air entering the pulmonary alveoli. [NIH] Hypoxia: Reduction of oxygen supply to tissue below physiological levels despite adequate perfusion of the tissue by blood. [EU] Hypoxic: Having too little oxygen. [NIH] Hysterectomy: Excision of the uterus. [NIH] Ibotenic Acid: Neurotoxic isoxazole substance found in Amanita muscaria and A. pantherina. It causes motor depression, ataxia, and changes in mood, perceptions and feelings, and is a potent excitatory amino acid agonist. [NIH] Ibuprofen: A nonsteroidal anti-inflammatory agent with analgesic properties used in the therapy of rheumatism and arthritis. [NIH] Id: The part of the personality structure which harbors the unconscious instinctive desires and strivings of the individual. [NIH] Idiopathic: Describes a disease of unknown cause. [NIH] Ileal: Related to the ileum, the lowest end of the small intestine. [NIH] Ileostomy: Surgical creation of an external opening into the ileum for fecal diversion or drainage. Loop or tube procedures are most often employed. [NIH] Ileum: The lower end of the small intestine. [NIH] Immune response: The activity of the immune system against foreign substances (antigens). [NIH] Immune system: The organs, cells, and molecules responsible for the recognition and disposal of foreign (\"non-self\") material which enters the body. [NIH] Immunity: Nonsusceptibility to the invasive or pathogenic effects of foreign microorganisms or to the toxic effect of antigenic substances. [NIH] Immunization: Deliberate stimulation of the host's immune response. Active immunization involves administration of antigens or immunologic adjuvants. Passive immunization involves administration of immune sera or lymphocytes or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow). [NIH] Immunodeficiency: The decreased ability of the body to fight infection and disease. [NIH] Immunodiffusion: Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction. [NIH] Immunoelectrophoresis: A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera. [NIH] Immunogenic: Producing immunity; evoking an immune response. [EU] Immunoglobulin: A protein that acts as an antibody. [NIH] Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents. [NIH] Immunology: The study of the body's immune system. [NIH] Immunophilin: A drug for the treatment of Parkinson's disease. [NIH] Immunosuppressive: Describes the ability to lower immune system responses. [NIH]

384 Muscles Immunotherapy: Manipulation of the host's immune system in treatment of disease. It includes both active and passive immunization as well as immunosuppressive therapy to prevent graft rejection. [NIH] Impairment: In the context of health experience, an impairment is any loss or abnormality of psychological, physiological, or anatomical structure or function. [NIH] Implant radiation: A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near the tumor. Also called [NIH] Implantation: The insertion or grafting into the body of biological, living, inert, or radioactive material. [EU] Impotence: The inability to perform sexual intercourse. [NIH] In situ: In the natural or normal place; confined to the site of origin without invasion of neighbouring tissues. [EU] In vitro: In the laboratory (outside the body). The opposite of in vivo (in the body). [NIH] In vivo: In the body. The opposite of in vitro (outside the body or in the laboratory). [NIH] Incision: A cut made in the body during surgery. [NIH] Incompetence: Physical or mental inadequacy or insufficiency. [EU] Incontinence: Inability to control the flow of urine from the bladder (urinary incontinence) or the escape of stool from the rectum (fecal incontinence). [NIH] Incubation: The development of an infectious disease from the entrance of the pathogen to the appearance of clinical symptoms. [EU] Incubation period: The period of time likely to elapse between exposure to the agent of the disease and the onset of clinical symptoms. [NIH] Indicative: That indicates; that points out more or less exactly; that reveals fairly clearly. [EU] Induction: The act or process of inducing or causing to occur, especially the production of a specific morphogenetic effect in the developing embryo through the influence of evocators or organizers, or the production of anaesthesia or unconsciousness by use of appropriate agents. [EU] Inertia: Inactivity, inability to move spontaneously. [EU] Infarction: A pathological process consisting of a sudden insufficient blood supply to an area, which results in necrosis of that area. It is usually caused by a thrombus, an embolus, or a vascular torsion. [NIH] Infection: 1. Invasion and multiplication of microorganisms in body tissues, which may be clinically unapparent or result in local cellular injury due to competitive metabolism, toxins, intracellular replication, or antigen-antibody response. The infection may remain localized, subclinical, and temporary if the body's defensive mechanisms are effective. A local infection may persist and spread by extension to become an acute, subacute, or chronic clinical infection or disease state. A local infection may also become systemic when the microorganisms gain access to the lymphatic or vascular system. 2. An infectious disease. [EU] Infiltration: The diffusion or accumulation in a tissue or cells of substances not normal to it or in amounts of the normal. Also, the material so accumulated. [EU] Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function. [NIH] Infusion: A method of putting fluids, including drugs, into the bloodstream. Also called

Dictionary 385 intravenous infusion. [NIH] Ingestion: Taking into the body by mouth [NIH] Inhalation: The drawing of air or other substances into the lungs. [EU] Initiation: Mutation induced by a chemical reactive substance causing cell changes; being a step in a carcinogenic process. [NIH] Inlay: In dentistry, a filling first made to correspond with the form of a dental cavity and then cemented into the cavity. [NIH] Inner ear: The labyrinth, comprising the vestibule, cochlea, and semicircular canals. [NIH] Innervation: 1. The distribution or supply of nerves to a part. 2. The supply of nervous energy or of nerve stimulus sent to a part. [EU] Inositol: An isomer of glucose that has traditionally been considered to be a B vitamin although it has an uncertain status as a vitamin and a deficiency syndrome has not been identified in man. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1379) Inositol phospholipids are important in signal transduction. [NIH] Inositol 1,4,5-Trisphosphate: Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin. [NIH] Insight: The capacity to understand one's own motives, to be aware of one's own psychodynamics, to appreciate the meaning of symbolic behavior. [NIH] Insulin: A protein hormone secreted by beta cells of the pancreas. Insulin plays a major role in the regulation of glucose metabolism, generally promoting the cellular utilization of glucose. It is also an important regulator of protein and lipid metabolism. Insulin is used as a drug to control insulin-dependent diabetes mellitus. [NIH] Insulin-dependent diabetes mellitus: A disease characterized by high levels of blood glucose resulting from defects in insulin secretion, insulin action, or both. Autoimmune, genetic, and environmental factors are involved in the development of type I diabetes. [NIH] Insulin-like: Muscular growth factor. [NIH] Intercostal: Situated between the ribs. [EU] Interferon: A biological response modifier (a substance that can improve the body's natural response to disease). Interferons interfere with the division of cancer cells and can slow tumor growth. There are several types of interferons, including interferon-alpha, -beta, and - gamma. These substances are normally produced by the body. They are also made in the laboratory for use in treating cancer and other diseases. [NIH] Interferon-alpha: One of the type I interferons produced by peripheral blood leukocytes or lymphoblastoid cells when exposed to live or inactivated virus, double-stranded RNA, or bacterial products. It is the major interferon produced by virus-induced leukocyte cultures and, in addition to its pronounced antiviral activity, it causes activation of NK cells. [NIH] Intermediate Filaments: Cytoplasmic filaments intermediate in diameter (about 10 nanometers) between the microfilaments and the microtubules. They may be composed of any of a number of different proteins and form a ring around the cell nucleus. [NIH] Intermittent: Occurring at separated intervals; having periods of cessation of activity. [EU] Intermittent Claudication: A symptom complex characterized by leg pain and weakness brought on by walking, with the disappearance of the symptoms following a brief rest. [NIH] Internal Medicine: A medical specialty concerned with the diagnosis and treatment of

386 Muscles diseases of the internal organ systems of adults. [NIH] Internal radiation: A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near the tumor. Also called brachytherapy, implant radiation, or interstitial radiation therapy. [NIH] Interneurons: Most generally any neurons which are not motor or sensory. Interneurons may also refer to neurons whose axons remain within a particular brain region as contrasted with projection neurons which have axons projecting to other brain regions. [NIH] Interstitial: Pertaining to or situated between parts or in the interspaces of a tissue. [EU] Intervertebral: Situated between two contiguous vertebrae. [EU] Intervertebral Disk Displacement: An intervertebral disk in which the nucleus pulposus has protruded through surrounding fibrocartilage. This occurs most frequently in the lower lumbar region. [NIH] Intestinal: Having to do with the intestines. [NIH] Intestinal Mucosa: The surface lining of the intestines where the cells absorb nutrients. [NIH] Intestine: A long, tube-shaped organ in the abdomen that completes the process of digestion. There is both a large intestine and a small intestine. Also called the bowel. [NIH] Intoxication: Poisoning, the state of being poisoned. [EU] Intracellular: Inside a cell. [NIH] Intramuscular: IM. Within or into muscle. [NIH] Intramuscular injection: IM. Injection into a muscle. [NIH] Intraocular: Within the eye. [EU] Intraocular pressure: Pressure of the fluid inside the eye; normal IOP varies among individuals. [NIH] Intravenous: IV. Into a vein. [NIH] Intrinsic: Situated entirely within or pertaining exclusively to a part. [EU] Intrinsic Factor: A glycoprotein secreted by the cells of the gastric glands that is required for the absorption of vitamin B 12. Deficiency of intrinsic factor results in pernicious anemia. [NIH] Invasive: 1. Having the quality of invasiveness. 2. Involving puncture or incision of the skin or insertion of an instrument or foreign material into the body; said of diagnostic techniques. [EU] Invertebrates: Animals that have no spinal column. [NIH] Involuntary: Reaction occurring without intention or volition. [NIH] Ions: An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as cations; those with a negative charge are anions. [NIH] Iris: The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium. [NIH] Irradiation: The use of high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from materials called radioisotopes. Radioisotopes produce radiation and can be placed in or near the tumor or in the area near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation,

Dictionary 387 interstitial radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Irradiation is also called radiation therapy, radiotherapy, and x-ray therapy. [NIH] Ischemia: Deficiency of blood in a part, due to functional constriction or actual obstruction of a blood vessel. [EU] Isoenzyme: Different forms of an enzyme, usually occurring in different tissues. The isoenzymes of a particular enzyme catalyze the same reaction but they differ in some of their properties. [NIH] Isometric Contraction: Muscular contractions characterized by increase in tension without change in length. [NIH] Iteration: Unvarying repetition or unvarying persistence. [NIH] Joint: The point of contact between elements of an animal skeleton with the parts that surround and support it. [NIH] Joint Capsule: The sac enclosing a joint. It is composed of an outer fibrous articular capsule and an inner synovial membrane. [NIH] Kainic Acid: (2S-(2 alpha,3 beta,4 beta))-2-Carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid. Ascaricide obtained from the red alga Digenea simplex. It is a potent excitatory amino acid agonist at some types of excitatory amino acid receptors and has been used to discriminate among receptor types. Like many excitatory amino acid agonists it can cause neurotoxicity and has been used experimentally for that purpose. [NIH] Kb: A measure of the length of DNA fragments, 1 Kb = 1000 base pairs. The largest DNA fragments are up to 50 kilobases long. [NIH] Keratin: A class of fibrous proteins or scleroproteins important both as structural proteins and as keys to the study of protein conformation. The family represents the principal constituent of epidermis, hair, nails, horny tissues, and the organic matrix of tooth enamel. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms an alpha-helix, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. [NIH] Keratitis: Inflammation of the cornea. [NIH] Ketamine: A cyclohexanone derivative used for induction of anesthesia. Its mechanism of action is not well understood, but ketamine can block NMDA receptors (receptors, N- Methyl-D-Aspartate) and may interact with sigma receptors. [NIH] Keto: It consists of 8 carbon atoms and within the endotoxins, it connects poysaccharide and lipid A. [NIH] Kidney Disease: Any one of several chronic conditions that are caused by damage to the cells of the kidney. People who have had diabetes for a long time may have kidney damage. Also called nephropathy. [NIH] Kidney Failure: The inability of a kidney to excrete metabolites at normal plasma levels under conditions of normal loading, or the inability to retain electrolytes under conditions of normal intake. In the acute form (kidney failure, acute), it is marked by uremia and usually by oliguria or anuria, with hyperkalemia and pulmonary edema. The chronic form (kidney failure, chronic) is irreversible and requires hemodialysis. [NIH] Kinesin: A microtubule-associated mechanical adenosine triphosphatase, that uses the energy of ATP hydrolysis to move organelles along microtubules toward the plus end of the microtubule. The protein is found in squid axoplasm, optic lobes, and in bovine brain. Bovine kinesin is a heterotetramer composed of two heavy (120 kDa) and two light (62 kDa) chains. EC 3.6.1.-. [NIH]

388 Muscles Kinetic: Pertaining to or producing motion. [EU] Knee Injuries: Injuries to the knee or the knee joint. [NIH] Labile: 1. Gliding; moving from point to point over the surface; unstable; fluctuating. 2. Chemically unstable. [EU] Labyrinth: The internal ear; the essential part of the organ of hearing. It consists of an osseous and a membranous portion. [NIH] Lacerations: Torn, ragged, mangled wounds. [NIH] Lacrimal: Pertaining to the tears. [EU] Laminin: Large, noncollagenous glycoprotein with antigenic properties. It is localized in the basement membrane lamina lucida and functions to bind epithelial cells to the basement membrane. Evidence suggests that the protein plays a role in tumor invasion. [NIH] Large Intestine: The part of the intestine that goes from the cecum to the rectum. The large intestine absorbs water from stool and changes it from a liquid to a solid form. The large intestine is 5 feet long and includes the appendix, cecum, colon, and rectum. Also called colon. [NIH] Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals. [NIH] Laryngeal: Having to do with the larynx. [NIH] Laryngoscopy: Examination, therapy, or surgery of the interior of the larynx performed with a specially designed endoscope. [NIH] Larynx: An irregularly shaped, musculocartilaginous tubular structure, lined with mucous membrane, located at the top of the trachea and below the root of the tongue and the hyoid bone. It is the essential sphincter guarding the entrance into the trachea and functioning secondarily as the organ of voice. [NIH] Latency: The period of apparent inactivity between the time when a stimulus is presented and the moment a response occurs. [NIH] Lectins: Protein or glycoprotein substances, usually of plant origin, that bind to sugar moieties in cell walls or membranes and thereby change the physiology of the membrane to cause agglutination, mitosis, or other biochemical changes in the cell. [NIH] Lens: The transparent, double convex (outward curve on both sides) structure suspended between the aqueous and vitreous; helps to focus light on the retina. [NIH] Lentivirus: A genus of the family Retroviridae consisting of non-oncogenic retroviruses that produce multi-organ diseases characterized by long incubation periods and persistent infection. Lentiviruses are unique in that they contain open reading frames (ORFs) between the pol and env genes and in the 3' env region. Five serogroups are recognized, reflecting the mammalian hosts with which they are associated. HIV-1 is the type species. [NIH] Leptin: A 16-kD peptide hormone secreted from white adipocytes and implicated in the regulation of food intake and energy balance. Leptin provides the key afferent signal from fat cells in the feedback system that controls body fat stores. [NIH] Lethal: Deadly, fatal. [EU] Leucine: An essential branched-chain amino acid important for hemoglobin formation. [NIH] Leucocyte: All the white cells of the blood and their precursors (myeloid cell series, lymphoid cell series) but commonly used to indicate granulocytes exclusive of lymphocytes. [NIH] Leukemia: Cancer of blood-forming tissue. [NIH]

Dictionary 389 Leukocytes: White blood cells. These include granular leukocytes (basophils, eosinophils, and neutrophils) as well as non-granular leukocytes (lymphocytes and monocytes). [NIH] Libido: The psychic drive or energy associated with sexual instinct in the broad sense (pleasure and love-object seeking). It may also connote the psychic energy associated with instincts in general that motivate behavior. [NIH] Library Services: Services offered to the library user. They include reference and circulation. [NIH] Ligament: A band of fibrous tissue that connects bones or cartilages, serving to support and strengthen joints. [EU] Ligands: A RNA simulation method developed by the MIT. [NIH] Ligation: Application of a ligature to tie a vessel or strangulate a part. [NIH] Limbic: Pertaining to a limbus, or margin; forming a border around. [EU] Limbic System: A set of forebrain structures common to all mammals that is defined functionally and anatomically. It is implicated in the higher integration of visceral, olfactory, and somatic information as well as homeostatic responses including fundamental survival behaviors (feeding, mating, emotion). For most authors, it includes the amygdala, epithalamus, gyrus cinguli, hippocampal formation (see hippocampus), hypothalamus, parahippocampal gyrus, septal nuclei, anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, http://rprcsgi.rprc.washington.edu/neuronames/index.html (September 2, 1998)). [NIH] Lingual Nerve: A sensory branch of the mandibular nerve, which is part of the trigeminal (5th cranial) nerve. The lingual nerve carries general afferent fibers from the anterior two- thirds of the tongue, the floor of the mouth, and the mandibular gingivae. [NIH] Linkage: The tendency of two or more genes in the same chromosome to remain together from one generation to the next more frequently than expected according to the law of independent assortment. [NIH] Linoleic Acids: Eighteen-carbon essential fatty acids that contain two double bonds. [NIH] Lip: Either of the two fleshy, full-blooded margins of the mouth. [NIH] Lipid: Fat. [NIH] Lipodystrophy: A collection of rare conditions resulting from defective fat metabolism and characterized by atrophy of the subcutaneous fat. They include total, congenital or acquired, partial, abdominal infantile, and localized lipodystrophy. [NIH] Lipoprotein: Any of the lipid-protein complexes in which lipids are transported in the blood; lipoprotein particles consist of a spherical hydrophobic core of triglycerides or cholesterol esters surrounded by an amphipathic monolayer of phospholipids, cholesterol, and apolipoproteins; the four principal classes are high-density, low-density, and very-low- density lipoproteins and chylomicrons. [EU] Lipoprotein Lipase: An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. The enzyme hydrolyzes triacylglycerols in chylomicrons, very-low-density lipoproteins, low-density lipoproteins, and diacylglycerols. It occurs on capillary endothelial surfaces, especially in mammary, muscle, and adipose tissue. Genetic deficiency of the enzyme causes familial hyperlipoproteinemia Type I. (Dorland, 27th ed) EC 3.1.1.34. [NIH] Liver: A large, glandular organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile. [NIH] Liver scan: An image of the liver created on a computer screen or on film. A radioactive

390 Muscles substance is injected into a blood vessel and travels through the bloodstream. It collects in the liver, especially in abnormal areas, and can be detected by the scanner. [NIH] Localization: The process of determining or marking the location or site of a lesion or disease. May also refer to the process of keeping a lesion or disease in a specific location or site. [NIH] Localized: Cancer which has not metastasized yet. [NIH] Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms. [NIH] Locomotor: Of or pertaining to locomotion; pertaining to or affecting the locomotive apparatus of the body. [EU] Long-Term Care: Care over an extended period, usually for a chronic condition or disability, requiring periodic, intermittent, or continuous care. [NIH] Loop: A wire usually of platinum bent at one end into a small loop (usually 4 mm inside diameter) and used in transferring microorganisms. [NIH] Low Back Pain: Acute or chronic pain in the lumbar or sacral regions, which may be associated with musculo-ligamentous sprains and strains; intervertebral disk displacement; and other conditions. [NIH] Low-density lipoprotein: Lipoprotein that contains most of the cholesterol in the blood. LDL carries cholesterol to the tissues of the body, including the arteries. A high level of LDL increases the risk of heart disease. LDL typically contains 60 to 70 percent of the total serum cholesterol and both are directly correlated with CHD risk. [NIH] Lower Esophageal Sphincter: The muscle between the esophagus and stomach. When a person swallows, this muscle relaxes to let food pass from the esophagus to the stomach. It stays closed at other times to keep stomach contents from flowing back into the esophagus. [NIH] Lucida: An instrument, invented by Wollaton, consisting essentially of a prism or a mirror through which an object can be viewed so as to appear on a plane surface seen in direct view and on which the outline of the object may be traced. [NIH] Lumbar: Pertaining to the loins, the part of the back between the thorax and the pelvis. [EU] Lumen: The cavity or channel within a tube or tubular organ. [EU] Lunate: A curved sulcus of the lateral surface which forms the anterior limit of the visual cortex. [NIH] Lung volume: The amount of air the lungs hold. [NIH] Lupus: A form of cutaneous tuberculosis. It is seen predominantly in women and typically involves the nasal, buccal, and conjunctival mucosa. [NIH] Lymph: The almost colorless fluid that travels through the lymphatic system and carries cells that help fight infection and disease. [NIH] Lymph node: A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Also known as a lymph gland. Lymph nodes are spread out along lymphatic vessels and contain many lymphocytes, which filter the lymphatic fluid (lymph). [NIH] Lymphatic: The tissues and organs, including the bone marrow, spleen, thymus, and lymph nodes, that produce and store cells that fight infection and disease. [NIH] Lymphatic system: The tissues and organs that produce, store, and carry white blood cells that fight infection and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes and a network of thin tubes that carry lymph and white blood cells.

Dictionary 391 These tubes branch, like blood vessels, into all the tissues of the body. [NIH] Lymphocyte: A white blood cell. Lymphocytes have a number of roles in the immune system, including the production of antibodies and other substances that fight infection and diseases. [NIH] Lymphoid: Referring to lymphocytes, a type of white blood cell. Also refers to tissue in which lymphocytes develop. [NIH] Lymphoma: A general term for various neoplastic diseases of the lymphoid tissue. [NIH] Lysine: An essential amino acid. It is often added to animal feed. [NIH] Lysosome: A sac-like compartment inside a cell that has enzymes that can break down cellular components that need to be destroyed. [NIH] Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques. [NIH] Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (magnetic resonance imaging). [NIH] Malabsorption: Impaired intestinal absorption of nutrients. [EU] Malformation: A morphologic defect resulting from an intrinsically abnormal developmental process. [EU] Malignant: Cancerous; a growth with a tendency to invade and destroy nearby tissue and spread to other parts of the body. [NIH] Malnutrition: A condition caused by not eating enough food or not eating a balanced diet. [NIH] Mammary: Pertaining to the mamma, or breast. [EU] Mandible: The largest and strongest bone of the face constituting the lower jaw. It supports the lower teeth. [NIH] Mandibular Nerve: A branch of the trigeminal (5th cranial) nerve. The mandibular nerve carries motor fibers to the muscles of mastication and sensory fibers to the teeth and gingivae, the face in the region of the mandible, and parts of the dura. [NIH] Manifest: Being the part or aspect of a phenomenon that is directly observable : concretely expressed in behaviour. [EU] Masseter Muscle: A masticatory muscle whose action is closing the jaws. [NIH] Mastication: The act and process of chewing and grinding food in the mouth. [NIH] Masticatory: 1. subserving or pertaining to mastication; affecting the muscles of mastication. 2. a remedy to be chewed but not swallowed. [EU] Maxillary: Pertaining to the maxilla : the irregularly shaped bone that with its fellow forms the upper jaw. [EU] Maxillary Nerve: The intermediate sensory division of the trigeminal (5th cranial) nerve. The maxillary nerve carries general afferents from the intermediate region of the face including the lower eyelid, nose and upper lip, the maxillary teeth, and parts of the dura. [NIH] Meat: The edible portions of any animal used for food including domestic mammals (the major ones being cattle, swine, and sheep) along with poultry, fish, shellfish, and game. [NIH]

392 Muscles Meatus: A canal running from the internal auditory foramen through the petrous portion of the temporal bone. It gives passage to the facial and auditory nerves together with the auditory branch of the basilar artery and the internal auditory veins. [NIH] Mechanical ventilation: Use of a machine called a ventilator or respirator to improve the exchange of air between the lungs and the atmosphere. [NIH] Mechanoreceptors: Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptors include hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non- neural accessory structures. [NIH] Medial: Lying near the midsaggital plane of the body; opposed to lateral. [NIH] Median Nerve: A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. [NIH] Mediate: Indirect; accomplished by the aid of an intervening medium. [EU] MEDLINE: An online database of MEDLARS, the computerized bibliographic Medical Literature Analysis and Retrieval System of the National Library of Medicine. [NIH] Meiosis: A special method of cell division, occurring in maturation of the germ cells, by means of which each daughter nucleus receives half the number of chromosomes characteristic of the somatic cells of the species. [NIH] Melanin: The substance that gives the skin its color. [NIH] Melanocytes: Epidermal dendritic pigment cells which control long-term morphological color changes by alteration in their number or in the amount of pigment they produce and store in the pigment containing organelles called melanosomes. Melanophores are larger cells which do not exist in mammals. [NIH] Melanoma: A form of skin cancer that arises in melanocytes, the cells that produce pigment. Melanoma usually begins in a mole. [NIH] Membrane: A very thin layer of tissue that covers a surface. [NIH] Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation. [NIH] Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. [NIH] Meninges: The three membranes that cover and protect the brain and spinal cord. [NIH] Meningitis: Inflammation of the meninges. When it affects the dura mater, the disease is termed pachymeningitis; when the arachnoid and pia mater are involved, it is called leptomeningitis, or meningitis proper. [EU] Meniscus: A fibro-cartilage within a joint, especially of the knee. [NIH] Menopause: Permanent cessation of menstruation. [NIH] Menstrual Cycle: The period of the regularly recurring physiologic changes in the endometrium occurring during the reproductive period in human females and some primates and culminating in partial sloughing of the endometrium (menstruation). [NIH] Menstruation: The normal physiologic discharge through the vagina of blood and mucosal