Presentation Blood and Cardiovascular System

Module 6: Blood and the Cardiovascular System BIOT 106 - Summary of Human Anatomy and Physiology

Blood  Is the only liquid tissue in the organism, classified as a connective tissue. Blood is composed of:  Live cells  Formed elements  Inert Liquid Matrix  Plasma  If put in a centrifuge Erythrocytes would sink to the bottom (45% of blood, a percentage known as hematocrit) the leukocytic layer, contain leukocytes and platelets (less than 1% of the blood) Leukocytic layer is a thin, white layer in between erythocytes and the plasma elevates to the superior part (55% of the blood)

Blood

Physical Characteristics of Blood  Blood rich in oxygen is scarlet red, while blood poor in oxygen is dark red  pH must remain between 7.35- 7.45  Temperature of blood is slightly superior to body temperature 100.4 ° ​F  In a healthy man, blood volume is approximately 5.6-6 liters  Bloods contributes 8% of body weight

Blood Plasma  Composed approximately of 90% water  Includes many dissolved substances  Nutrients  Salts ( electrolytes)  Respiratory gases  Hormones  Plasmatic proteins  Waste products This Photo by Unknown Author is licensed under CC BY-NC-ND

Formed Elements Erythrocytes (RBCs) • The principle function is transport oxygen • Essentialy sacs of hemoglobin • There are 5 million red blood cells by cubic millimeter of blood Hemoglobin • Iron contained in proteins • It strongly attaches to oxygen • Normal blood contains 12 to 18 g of hemoglobin by 100 ml of blood • Anemia is a decrease in the capacity of transport of oxygen in the blood

Formed Elements Leukocytes(white blood cells) • Crucial in the defense of the body against diseases • Capable of moving in and out of blood vessels ( diapédesis ) • Abnormal increase of leukocytes (leukocytosis). Recount of leukocytes over 11.000 leukocytes / mm3. generally indicates infection Leukopenia ( abnormal decrease of leukocytes under 4000 leu./ mm • Commonly caused by certain medication such as corticosteroids and anti-cancer agents. Leukemia • The bone marrow turns cancerous, results in an excess of CMB

Types of Leukocytes  Granulocytes This Photo by Unknown Author is licensed under CC BY  neutrophils,  eosynophils  and basophils  Agranulocytes  Lymphocytes  and monocytes

Leukocyte values Neutrophils Lymphocytes Monocytes Eosinophils Basophils •3.000-7.000 in •Function as part •Function as •Funtion; kill •Release of one cubic of the immune macrophages parasite worms histamine ( millimeter of response and perfomr a vasodilatator ) in blood (40-70 % •Important in the role in allergy inflammation of white blood •B lymphocytes fight against attacks sites cells) produce chronic infection antibodies •100-400 in a •20-50 basophils •100-700 cubic millimeter in one cubic •T lymphocytes monocytes per of blood (1-4 % millmeter of are implied in cubic millimeter of white blood blood (0-1 % of the rejection of of blood ( 4-8 % cells) white blood the implant, the of white blood cells) fight against cells) tumors and viruses •1.500-3.000 lymphocytes in a cubic millimeter of blood ( 20-45 % of white blood cells)

Platelets Hematopoiesis • Derived from the rupture of • The formation of blood cells are multinucleic cells produced in the red bone marrow. All (megacariocytes ) blood cells are derived from a common mother cell (hemocytoblast) • Needed for the process of coagulation Differentiation hemocytoblast • The recount of platelets • Lymphoid mother cell produces ranges from 150.000 to lymphocytes 400.000 per cubic millimeter of blood • Myeloid mother cell produces all other formed elements • 300.000 is considered a normal number of platelets per cubic millimeter of blood

Formation of Erythrocytes  Incapable of dividing, growing, or synthesizing proteins, they waste away in 100 to 120 days. When they waste away, red blood cells are eliminated by phagocytes in the spleen or liver  Lost cells are substituted by division of hemocytoblasts in the red bone marrow

Control of Erythrocyte Production  The rate is controlled by a 1 2 hormone (erythropoietin ) Kidney produces Bone marrow  The kidneys produce the erythropoietin produces red blood majority of eryhtropoietin cells as a response to reduced 4 levels of oxygen in the 3 blood Oxygen is made available to the Red blood cells carry oxygen  Homeostasis is maintained organs through the bloodstream by the negative vote of oxygen levels in the blood

Formation of white blood cells and platelets Controlled by hormones Stimulating factors of colonies (CSF) and bone marrow interleukins message to generate leukocytes Thrombopoietin stimulates the production of platelets

Blood groups and transfusions  Great blood losses have severe  ABO blood groups consequences. Transfusions are the only  Based on the absence or presence of two antigens way to replace blood quickly. Transfused  Type A blood must be from the same blood group  Type B  The presence of both antigens A and B is called type AB  The lack of these antigens is called type O

ABO Blood Groups  Blood group AB may Table of Blood Types receive A, B, AB and O blood, it is the universal recipient  Blood group B may reveive O and B blood  Blood group A may receive A and O blood  Type O blood may receive O blood. It is the universal donor.

The Cardiovascular System  It is a closed system of the heart and blood vessels, the heart pumps blood into blood vessels, allowing the blood to circulate to all parts of the body.  The functions of the cardiovascular system are to supply oxygen and nutrients to cells and tissues, and eliminate carbon dioxide and other waste products from cells ans tissues.

The Heart  Located in the thorax between the lungs in the inferior mediastinum  Orientation  The apex is the point guided towards the left hip, and the base, which is the widest part towards the right shoulder  It is the size of a fist

The Heart Heart Linings Heart Walls • The pericardium is a • Has three layers double-walled sac: • Epicardium is the • Visceral pericardium outermost wall next to the heart; • Myocardium, the also known as the epicardium. middle layer • Endocardium, the • Parietal pericardium exterior layer that most internal layer covers the internal surface of the fibrous pericardium

The Heart: Chambers  The heart is a hollow organ. A partition divides it in a right and left side. It contains 4 cavities or hollow chambers:  Atria: are the superior chambers They are receptor chambers, due to the fact that blood enters the heart through veins that discharge in these superior cavities.  Ventricles: are the inferior chambers. Blood is pumped from the heart to the arteries that come out of the ventricles; so the ventricles are called discharge chambers. This Photo by Unknown Author is licensed under CC BY-SA-NC

The heart’s role in blood circulation  Systemic Circulation Blood flows from the left side of the heart through the body’s tissues and back into the right side of the heart  Pulmonary Circulation Blood flows from the right side of the heart to the lungs and towards the left side of the heart

The Heart: Valves This Photo by Unknown Author is licensed under CC BY-SA  Atrioventricular valves or AV: are 2 valves which separate the atrial chambers above and the ventricles below.  Bicuspid or mitral valve: located between the left atrium and ventricle.  Tricuspid: located between the right atrium and ventricle  Valve Function  The function of these valves is to prevent the retrograde flow of blood towards the atria when the ventricles contract.  Tendinous cords: connect the AV valves to the walls of the heart.

Cardiac Circulation This Photo by Unknown Author is licensed under CC BY-SA  Blood that enters the right atrium comes from the inferior and superior cava vein. The right side receives poorly oxigenated blood from these veins. After entering the right atrium, it is pumped to the right ventricle through the tricuspid valve. When the ventricles contract, the blood is pumped to the pulmonary artery,through the pulmonary valve,to the lungs where oxygen is added and carbon dioxide is lost.  Blood rich in oxygen returns to the left atrium through the 4 pulmonary veins, then passes to the left ventricle through the mitral valve. When the left ventricle contracts, blood is pumped to the entire body through the aortic valve.

 Blood circulation by the heart is also separate and functions as two different pumps. Pulmonary circulation implies the movement of blood from the right ventricle to the lungs and the systemic cirulation implies the movement of blood from the left ventricle through the entire body. This Photo by Unknown Author is licensed under CC BY-SA-NC

Blood Supply to the Cardiac Muscle This Photo by Unknown Author is licensed under CC BY  Blood flows towards the cardiac muscle by way of 2 small vessels: right and left coronary arteries.  The coronary arteries are the first branches of the aorta. The orifices on these small vessels are located behind the valves of the aortic semilunar valve. During ventricular diastole, blood from the aorta passing behind the aortic valve may pass to the coronary arteries.

The Heart: Even though cardiac rhythm is Conduction controlled by autonomous nervous System signals, the heart has its own conduction system to coordinate contractions during the cardiac cycle. All cardiac fibers are electrically related. The intercalar discs are the electric connectors which join muscular fibers in one single unit. Because of it, the walls of both atria contract almost at the same time due to their fibers being electrically related. The same happens in the ventricles.

 Four structures immersed in the wall of the heart are specialized in generating strong impulses and driving them quickly to determined regions of the thoracic wall. These make sure the atria and then the ventricles contract effectively.  Sinoatrial node, known as SA node, or pacemaker  Atrioventricular Node or AV  AV Fascicle or Bundle of His  Purkinje fibers This Photo by Unknown Author is licensed under CC BY

 Conduction starts in the pacemaker of the heart or the SA node (sinoatrial). From there it extends in all directions through the atria. This makes the atrial fibers to contract. When the impulse reaches the AV node, this transmits by way of the fascicle of His and the Pukinje fibers until the ventricles which makes them contract. In normal conditions, each atrial beat is followed by a ventricular beat.

Cardiac Cycle  The beating of the heart is a regular and rhythmic process. Each complete beat is known as a cycle and includes the contraction (systole) and relaxation (diastole) of the atria and the ventricles. Each cycle takes an approximate time of 0.8 seconds to complete if the heart is beating at an average frequency of 72 bets per minute.  Systolic Volume: refers to the volume of blood impulsed by the ventricles during each beat.  Cardiac output: or volume of blood pumped by the ventricles per minute, ranges from around 5 liters in the normal adult at rest.

Cardiac Rhythm Regulation Decrease of Cardiac Frequency Parasympathetic nervous system High arterial pressure or high blood volume Decrease in venous return Sympathetic nervous system Crisis Low arterial pressure Hormones Epinephrin Thyroxine Exercise Decrease in blood volume Increase of the Cardiac Frequency

BLOOD VESSELS Arterial blood is pumped from the heart through a series of great blood vessels of distribution: the arteries. The biggest artery in the body is the aorta. Arteries are subdivided into smaller vessels until finally reaching the minute arterioles, which control the flow of microscopic exchange vessels known as capillaries. In the capillary beds the exchange of nutrients and respiratory gases is produced between the blood and the fluid around the cells.

BLOOD VESSELS  Blood leaves or is drained from the capillary beds to enter the small venules, which join each other and increase in size to become veins. The biggest veins are the superior cava vein and the inferior cava vein.  Arteries transport blood from the heart to the capillaries.  Veins transport blood to the heart from the capillaries and the capillaries transport blood from arterioles to venules.  The aorta transports blood from the left ventricle of the heart and the cava veins transport blood to the right atrium after having circulated the entire body.

Structure of Blood Vessels This Photo by Unknown Author is licensed under CC BY-SA  The arteries as well as the veins have 3 layers. The outermost layer is known as tunica externa. This layer is constituted by fibers of connetive tissue which reinforce the wall to prevent them from bursting from pressure.  The middle layer or tunica media in arteries and veins contains smooth muscular tissue. Nevertheless, this muscular layer is much thicker in arteries than in veins. What is the importance of this? That the thicker muscular layer in arterial walls is capable of resisting the highest pressures generated by the ventricular systole.  In arteries the tunica media plays a critical role to maintain arterial pressure and control the distribution of blood. The muscle of the arterial wall is smooth and it is controlled by the autonomous nervous system. The tunica media also contains a thin layer of fibrous elastic tissue.  Arteries and veins are lined with an internal layer of endothelial cells called tunica intima. The tunica intima is in reality one layer of squamous epithelial cells, called endothelium, and upholters the internal surface of the circulatory system.

Blood Vessel Functions Arteries and artetioles: • distribute blood from the heart to the capillaries in avery part of the body. In addition, through contraction amd relaxation. Arterioles help maintain normal arterial pressure. Venules and veins: • pick up blood from capillaries and return it to the heart. They also serve as blood reservoirs since they can expand to obtain a greater volume and can contract to contain a minor volume. Capillaries • function as exchange vessels, ex: glucose and oxygen; leave capillary blood towards the interstitial fluid and to the cells. Carbon dioxide and other substances move the opposite way, enter the capillary blood from cells. There is also an exchange of fluids between capillaries and the interstitial fluid.

This Photo by Unknown Author is licensed under CC BY-SA

Principle Arteries in Systemic Circulation Arterial Branches from the Arch of the Aorta ( BCS )  Arterial branches of the thoracic  Brachiocephlic trunk is divided into aorta  Right common carotid artery  Intercostal arteris enerve the muscles  Right subclavian artery in the thoracic wall  Left common carotid artery is divided into  Other branches of the thoracic aorta nourish  Left internal carotid artery (nourishes the brain) and left external carotid artery (nourish the skin and the head and neck muscles)  The lungs (bronchial arteries)  Branches of the left subclavian artery in the Vertebral artery  Esophagus ( esophageal arteries)  In the armpit, the subclavian artery becomes  Diaphragm ( phrenic arteries)  the axillary artery  brachial artery  radial and  ulnar arteries

Principle Arteries in Systemic Circulation Arterial branches of the abdominal aorta Arterial branches of the abdominal aorta Celiac tunk is the first branch of the Right and left renal arteries (nourish the abdominal aorta. It is only oe vessel that kidneys) possesses three branches: Right and left gonadal arteries Left gastric artery (stomach ) Splenic artery (spleen ) Ovarian arteries in women nourish the ovaries Common hepatic artery (liver) Testicular arteries in men nourish the testicles The superior mesenteric artery nourishes the Lumbar arteries serve the muscles of the greater part of the small intestine and the first abdomen and trunk half of the large intestine

Principle Arteries in Systemic Circulation  Branches of the abdominal aorta  Inferior mesenteric artery serves the second half of the large intestine  Right and left common iliac arteries are the final branches of the aorta  Internal iliac arteries serve the pelvic organs  External iliac arteries enter the thighs are become femoral artery popliteal artery which divides and forms anterior and posterior tibial arteries

Principle Veins in Systemic Circulation  Superior and inferior cava veins  Veins that drain in the superior cava enter the right atrium of the heart vein  Superior cava vein drains the head  Radial and ulnar veins → Brachial and arms vein → Axillary vein  Inferior cava vein drains the inferior  These veins drain the arms part of the body  Cephalic vein drains the lateral part of the arm and discharges in the axillary vein  Basilic vein drains the medial side of the arm and discharges in the brachial vein  Basilic and cephalic veins are attached in the median ulnar vein (elbow area)

Principle Veins in Systemic Circulation  Veins that drain in the superior cava vein  Veins that drain in the superior cava vein  Subclavian vein receives  Left and right brachiocephalic veins  The venous blood from the arm thorugh receive venoous blood from the axillary vein  Subclavian veins  The venous blood from the skin and muscles through the external jugular vein  Vertebral veins  Vertebral vein drains the posterior part of  Internal jugular veins the head  Brachiocephalic veins join to form the  Internal jugular vein drains the dural superior cava vein → right atrium of sinuses of the brain the heart  Azygos vein is a unique vein that drains the thorax

Principle Veins in Systemic Circulation  Veins that drain in the inferior cava  Veins that drain in the inferior cava vein vein  Anterior and posterior tibial veins  Right gonadal vein drains the right and the fibular vein drain the legs ovary in women and the right testicle in men  Posterior tibial vein → popliteal vein → → femoral vein, external iliac vein  Left gonadal vein discharges in the left renal vein  Great saphenous veins (longest veins in the body) receive the superficial  Right and left renal veins drain the drainage of the legs kidneys V  Each common iliac vein (left and  Hepatic portal vein drains the right) are formed by the union of the digestive organs and travels through internal and external iliac veins on the liver before entering in the each side systemic circulation

Arterial Supply to the Brain  Internal carotid arteries divide into Willis polygon  Anterior and medial cerebral arteries  Anterior and posterior blood supplies are joined by small arterial branches  These arteries supply the most part of that communicate the brain  The result is a complete cirle of  Vertebral arteries join once inside the connecting blood vessels called the cranium to form the basilar artery cerebral arterial circle or the Willis polygon  Basilar artery nourishes the brainstem and the cerebellum  The posterior cerebral artery forms from the division of the basilar artery  These arteries nourish the posterior brain