Module 5. Cardiovascular System and Blood

Haematology and Coagulation • HCT volume of red cells • Plasma – fluid in fresh blood • Serum – Fluid after blood has clotted • Plasma – serum + fibrinogen and clotting factors

What causes haemolysis? Patient Related Machine Related • Autoimmune • Centrifuge • Kinks in lines condition • Overheating • Disease – TTP – Sickle Cell Disease – Malaria – Incompatible blood transfusion

Haematology and Coagulation Leukocytes 3.2 – 10 x 10³ cells/������������ Polynuclear/granulocytes Mononuclear Cells Neutrophils Monocytes Eosinophils Lymphocytes Basophils

• 50-80% • Phagocytosis of foreign particles (bacteria and tissues)

• 1-4% • Can be phagocytic • Phagocytize antigen- antibody complexes • Mainly attack parasites too large to be engulfed by discharging a chemical mediator from granules • May trigger allergic reaction

• Less than 1% • Release histamine, heparin – Inflammation • Leads to an allergic reaction

Polynuclear/granulocytes PNCs • Neutrophils – Bacterial and Fungal • Eosinophils – Parasitic infections and allergic reactions • Basophils – Allergic Reaction

• 2-8% Mononuclear Cells MNCs • Circulate in blood before migrating to the tissues where they become macrophages • Clean up debris • High numbers in GIT, spleen, lymph nodes and alveoli

Lymphocytes Mononuclear Cells MNCs • 20-40% • Backbone of the immune system • Provides diversity, specificity, memory and the ability to distinguish between self and non-self

• Circulate until having contact Mononuclear Cells MNCs with foreign antigens • Trigger to become plasma cells • Give off immunoglobulin which initiates complement activation and phagocytosis

• Several different T cells (e.g. Mononuclear Cells MNCs Helper, Cytotoxic, Memory, Regulatory, NK) • Helper T secrete cytokines that activate Cytotoxic T – produces toxic granules which destroy pathogens

Mononuclear Cells MNCs • Monocytes – Phagocytosis of pathogens and debris • Lymphocytes – B >antibody production attack bacteria and toxins and assist with activation of T-cells – T >attack body cells when they are taken over by a virus or have become cancerous

Leukaemia • Lymphoid Leukaemia – Acute lymphocytic (or lymphoblastic) leukemia (ALL) – Chronic lymphocytic leukemia (CLL) • Myeloid Leukaemia – Acute myeloid (or myelogenous) leukaemia (AML) – Chronic myeloid (or myelogenous) leukemia (CML)

Haematopoietic stem cell • They are cells which have the potential to develop into many different blood cell types • Blood cancers, including Lymphomas, Leukaemias and Multiple Myeloma and some other diseases of immune system • CD34 is the cell surface marker antigen closely associated with stem cells

Haematology and Coagulation Platelets 150—400 x 10⁹/L • Menorrhagia • Petechiae • Purpura • Joint bleeding

Haemostasis Prevents the loss of blood through vessel walls

Coagulation

Coagulation Cascade • Synthesized mainly in the liver • 2 pathways – intrinsic and extrinsic • Both processes begins with factor X and ends in prothrombin to thrombin which converts fibrinogen to fibrin which forms a stable clot with a platelet plug





• Heparin increases antithrombin by a 1000 fold • Citrate binds with Ca • Warfarin interferes with the attachment of the vitamin K dependant factors (II, VII, IX, X) • Tissue Plasminogen activator (tPA) enhances the activity of Plasmin which breaks down fibrin clots and is used to clear poorly flowing CV lines

Plasma Specific weight Size Platelets 1.026 Lymphocytes 1.040 1-4 μm Monocytes 6-10 μm Basophils 1.050-1.061 10-30 μm Eosinophils 1.077 10-15 μm Neutrophils 1.080 9-15 μm Erythrocytes 1.082 12-15 μm 1.088 6-8 μm 1.100 7722

BLOOD TYPE ABO • The presence or absence of the antigens A and B on the red cell determines a person’s blood type • Blood type O doesn’t have A or B antigens, therefore is the universal red cell donor • Blood type AB has both A and B antigens, therefore is the universal recipient







Rh Factors • The presence or absence of the D antigen on a red cell determines whether an individual is Rh+ or Rh- • If your blood does contain the protein, your blood is said to be Rhesus positive (Rh+). If your blood does not contain the protein, your blood is said to be Rhesus negative (Rh-)

… continued • People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. • People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. • Rh + Can receive + or - • Rh - Can only receive -







• https://www.nobelprize.org/educational/medicine/bloodtypi nggame/gamev2/index.html

Human Leucocyte antigen

What is HLA typing?

What is HLA matching? • When two people share the same Human Leukocyte Antigens (abbreviated as HLA) they are said to be a \"match“ • their tissues are immunologically compatible with each other. • HLA are proteins that are located on the surface of the white blood cells and other tissues in the body.





3 general groups • HLA-A (59 types) • HLA-B(118 types) • HLA-DR (124 types)

Basic rule in HLA inheritance • 25% chance of inheriting all of the same HLA (same 2 haplotypes) of a siblings • 25% chance of not inheriting any of the same HLA (none of the same haplotypes) • 50% chance of sharing I haplotype with your siblings • Therefore:1 in 4 chance of being an identical match with your siblings.

ABO vs. HLA • The ABO blood group genetic system and the HLA genetic system are not inherited together. • just as your gene (the DNA) for eye colour is separate from your gene (the DNA) for your blood group, so is your DNA for HLA. All of these genes are inherited independently from each other.

What is PRA? • Percent Reactive Antibody – is the amount of HLA antibody present in a patient's serum.

Cardiac cycle continued The autonomic nervous system controls heart rate. The accelerator nerve of the sympathetic nervous system increases heart rate and the vagus nerve of the parasympathetic nervous system decreases heart rate. For most people, their resting heart rate is between 60 and 80 b.p.m. During exercise that can increase to as many as 200 beats per minute for an athlete; for the rest of us, 150 b.p.m.

arteries>arterioles> capillaries>venules>veins Arteries carry blood from the heart to the capillaries of the organs in the body. walls of arteries are thicker than those of veins to withstand the high pressure of blood Arterioles can dilate or constrict to alter their diameter and so alter the flow of blood through the organ supplied by that arteriole. 2 organs which always have the same blood flow are the brain and the kidneys

arteries>arterioles> capillaries>venules>veins Arterioles branch into capillaries they have a very large surface area and thin walls exchanges take place between the blood and the tissues of the body capillaries>venules>veins carry the blood back to the atria of the heart veins are thinner and less elastic than arteries Veins tend to run between the muscle larger veins contain valves that maintain the direction of blood-flow

Circulation →Left ventricle systemic circulation (body) → right atrium → right ventricle → pulmonary circulation (lungs) → left atrium → left ventricle

Systemic Circulation coronary circulation - supplying blood to the heart muscle (coronary artery) renal circulation – supplying blood to the kidneys (renal artery). Nearly 25% of the blood leaving the heart flows to the kidneys, which are pressure filters for waste. hepatic portal circulation- nutrients picked up by capillaries in the small intestines are transported directly to the liver in the hepatic portal vein, where excess nutrients are stored. This is about 70% of the liver’s blood supply. The liver also receives oxygenated blood from the hepatic artery, which branches off the aorta, and provides 30% of its blood. All blood leaves the liver through the hepatic vein.

Circulation systemic pulmonary renal coronary hepatic circulation circulation portal circulation



BLOOD PRESSURE

Goal of the Cardiovascul ar System: deliver blood to all parts of the body