BIOH122 Human Biological Science 2

Transcription

1 BIOH122 Human Biological Science 2 Session 2 Haematological System Haemostasis and Blood Groups Bioscience Department Endeavour College of Natural Health endeavour.edu.au

2 Session Plan o Platelets Properties Functions Thrombopoiesis o Haemostasis vascular spasm platelet plug formation blood clotting o Blood Groups and Blood Types ABO Blood Groups Rh Blood Groups o Hematological Disorders Endeavour College of Natural Health endeavour.edu.au 2

3 Platelets Endeavour College of Natural Health endeavour.edu.au 3

4 Platelets: Thrombocyte o Shape: Irregularly disc-shaped, Cell fragments o Size: 2-4 micron in diameter o Structure: contains many vesicles but no nucleus o Life span: only 5 to 9 days; aged and dead platelets are removed by fixed macrophages in the spleen and liver. o Normal platelet count: 150, ,000/µL of blood o Function: help stop blood loss from damaged vessels by forming a platelet plug. Their granules also contain chemicals that promote blood clotting. Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 4

5 Thrombopoiesis: Making Platelets o Thrombopoietin stimulates myeloid stem cells to produce platelets in bone marrow.. Each megakaryocyte splits into 2000 to 3000 fragments, enclosed by a piece of cell membrane. This is a platelet (thrombocyte). Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 5

6 Haemostasis:Blood Clotting Endeavour College of Natural Health endeavour.edu.au 6

7 Haemostasis o Stoppage of bleeding in a quick and localized fashion when blood vessels are damaged o Prevents haemorrhage (loss of a large amount of blood) o Mechanisms: Vascular spasm Platelet plug formation Blood clotting (coagulation = formation of fibrin threads) Endeavour College of Natural Health endeavour.edu.au 7

8 Vascular Spasm o Reflex contraction of smooth muscle of small blood vessels when arteries or arterioles are damaged. o Caused by damage to the smooth muscle of blood vessel, by substances released from activated platelets, and by reflexes initiated by pain receptors. o Can reduce blood loss for several hours until other mechanisms can take over o Only for small blood vessel or arteriole. Endeavour College of Natural Health endeavour.edu.au 8

9 Platelet Plug Formation o Platelets store a lot of chemicals in granules needed for platelet plug formation Alpha granules Clotting Factors (for coagulation cascade) Dense granules ADP, ATP, Ca+2, serotonin, fibrin-stabilizing factor, and enzymes that produce thromboxane A2 Endeavour College of Natural Health endeavour.edu.au 9

10 o Platelet Adhesion Platelet Plug Formation platelets stick to exposed collagen and damaged endothelial cells in vessel wall o Platelet Release Reaction platelets activated by adhesion extend projections & make contact release thromboxane A2, ADP, serotonin o Platelet Aggregation activated platelets stick together to form a mass called a platelet plug plug reinforced by fibrin threads formed during clotting process Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 10

11 Blood Clotting o Blood drawn from the body thickens into an insoluble protein gel o This gel separates into liquid (serum) and a clot of insoluble fibers (fibrin) in which the formed elements are trapped Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 11

12 Blood Clotting o Coagulation factors required for clotting are mostly in blood plasma o Identified by Roman numerals o Include: Ca+2, inactive enzymes synthesized by liver cells and substances released by platelets or damaged tissues o Thrombosis: Blood clots too easily and clotting occurs in an unbroken vessel o Haemorrhage: Blood takes too long to clot Endeavour College of Natural Health endeavour.edu.au 12

13 Blood Clotting Factors Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 13

14 Blood Clotting Cascade o Clotting is a cascade of reactions in which each clotting factor activates the next in a fixed sequence resulting in the formation of fibrin threads o Key Steps Formation of prothrombinase Prothrombinase and Ca+2 convert prothrombin into thrombin Thrombin converts soluble fibrinogen into insoluble fibrin threads Endeavour College of Natural Health endeavour.edu.au 14

15 Overview of the Clotting Cascade Extrinsic and Intrinsic Pathway Formation of prothrombinase Prothrombinase and Ca+2 convert prothrombin into thrombin Thrombin converts soluble fibrinogen into insoluble fibrin threads Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 15

16 o Damaged tissues leak tissue factor (thromboplastin) into bloodstream o Prothrombinase forms in seconds Extrinsic Pathway Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 16

17 o Activation occurs endothelium is damaged and platelets come in contact with collagen of blood vessel wall platelets are damaged releasing phospholipids o Requires several minutes for Prothrombinase to be produced Intrinsic Pathway Endeavour College of Natural Health endeavour.edu.au 17

18 Final Common Pathway o Prothrombinase + Ca+2 catalyze the conversion of prothrombin thrombin o Thrombin + Ca2+ converts fibrinogen fibrin threads activates fibrin stabilizing factor XIII Strengthened Fibrin threads & Clot retraction Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 18

19 Clot Retraction o Clots plug the ruptured area of the blood vessel o Platelets pull on fibrin threads causing clot retraction (tightening) trapped platelets release factor XIII stabilizing the fibrin threads Endeavour College of Natural Health endeavour.edu.au 19

20 Clotting Cascade : Positive Feedback o Positive feedback effects of thrombin o Thrombin + accelerates formation of prothrombinase activates platelets to release phospholipids Endeavour College of Natural Health endeavour.edu.au 20

21 Blood Vessel Repair Blood Vessel Repair: o Edges of damaged vessel are pulled together o Fibroblasts and endothelial cells repair the blood vessel Endeavour College of Natural Health endeavour.edu.au 21

22 Role of Vitamin K in Clotting o Adequate vitamin K is required for Normal clotting Fat soluble vitamin absorbed if lipids are present Absorption slowed if bile release is insufficient o Required for synthesis of 4 clotting factors by hepatocytes Factors II (prothrombin), VII, IX and X o Produced by bacteria in large intestine Endeavour College of Natural Health endeavour.edu.au 22

23 Haemostatic Control Mechanisms o Fibrinolytic system dissolves small, inappropriate clots and clots at a site of a completed repair fibrinolysis is dissolution of a clot o Inactive plasminogen is incorporated into the clot plasminogen becomes plasmin (fibrinolysin) which digests fibrin threads and inactivating fibrinogen, prothrombin, factors V, VIII, XII Endeavour College of Natural Health endeavour.edu.au 23

24 Haemostatic Control Mechanisms o Clot formation remains localized fibrin threads trap / absorbs thrombin blood disperses clotting factors o Endothelial cells and WBC produce prostacyclins that oppose thromboxane A2 (platelet adhesion and release) o Anticoagulants are present in blood and are produced by mast cells Endeavour College of Natural Health endeavour.edu.au 24

25 Haemostatic Disorders o Thrombosis: Clotting in an unbroken blood vessel Involves the Intrinsic pathway o Embolus: A thrombus (clot), bubble of air, fat from broken bones, or piece of debris transported by the bloodstream that moves from its site of origin. Endeavour College of Natural Health endeavour.edu.au 25

26 Anticoagulant Agents o Anticoagulants: suppress or prevent blood clotting o Patients who are at increased risk of forming blood clots may receive an anticoagulant drug Aspirin inhibits vasoconstriction and platelet aggregation through stopping production of Tx A2. heparin administered during haemodialysis and surgery warfarin (Coumadin ) antagonist to vitamin K so blocks synthesis of clotting factors slower than heparin Endeavour College of Natural Health endeavour.edu.au 26

27 Thrombolytic Agents o Thrombolytic agents: are injected to dissolve clots streptokinase or tissue plasminogen activator (t-pa) o Directly or indirectly activate plasminogen Used to dissolve coronary cerebral & pulmonary clots Endeavour College of Natural Health endeavour.edu.au 27

28 Blood Groups and Blood Types Endeavour College of Natural Health endeavour.edu.au 28

29 ABO Group o Agglutinogens: surface Antigens on Erythrocytes A or B, then both A and B, or neither called O o In the ABO system, Agglutinogens A and B found on the surface of RBCs determine blood types display only antigen A - blood type A display only antigen B - blood type B display both antigens A and B - blood type AB display neither antigen - blood type O Endeavour College of Natural Health endeavour.edu.au 29

30 ABO Blood Groups o Agglutinins : Antibodies present in plasma designated as anti-a and anti-b, that react with agglutinogens that are foreign to the individual. anti-a antibody reacts with antigen A anti-b antibody reacts with antigen B Endeavour College of Natural Health endeavour.edu.au 30

31 Blood Groups and Blood Types o RBC surfaces are marked by genetically determined glycoproteins and glycolipids distinguishes at least 24 different blood groups ABO, Rh, Lewis, Kell, Kidd and Duffy systems Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 31

32 Rh Blood Groups o Rh: Antigen was discovered in blood of Rhesus monkey o People with Rh agglutinogens on RBC surface are Rh+ve. Normal plasma contains no anti-rh antibodies o Antibodies develop only in Rh-ve blood type and only with exposure to the antigen transfusion of positive blood during a pregnancy with a positive blood type foetus o Transfusion reaction upon second exposure to the antigen results in haemolysis of the RBCs in the donated blood Endeavour College of Natural Health endeavour.edu.au 32

33 Haemolytic Disease of Newborn o Rh negative mother and Rh+ foetus will have mixing of blood at birth o Mother's body creates Rh antibodies unless she receives a RhoGam shot soon after first delivery, miscarriage or abortion RhoGam binds to loose foetal blood and removes it from her body before she reacts o In her second pregnancy, haemolytic disease of the newborn may develop causing haemolysis of the foetal RBCs Endeavour College of Natural Health endeavour.edu.au 33

34 Haemolytic Disease of Newborn Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 34

35 Transfusions o Transfusions: Transfer of whole blood, cells or plasma into the bloodstream of recipient used to treat anaemia or severe blood loss, clotting disorders, cancers, burns o Knowledge of blood type: Essential for safe transfusion of blood Forensics Anthropology studies to establish a relationship among races. Endeavour College of Natural Health endeavour.edu.au 35

36 Transfusion Reactions o Incompatible blood transfusions antigen-antibody complexes form between plasma antibodies and foreign proteins on donated RBC's (agglutination) donated RBCs become leaky (complement proteins) and burst loose haemoglobin causing kidney damage Endeavour College of Natural Health endeavour.edu.au 36

37 Universal Donors and Recipients o Universal recipients: People with type AB blood are called as they have no antibodies in plasma* o Universal donors: People with type O blood cell since they have no antigens on their cells* *only true if cross match the blood for other antigens Endeavour College of Natural Health endeavour.edu.au 37

38 Hematological Disorders Endeavour College of Natural Health endeavour.edu.au 38

39 Hematological Disorders o Anaemia o Sickle-cell o Haemophilia o Disseminated intravascular clotting o Acute leukaemia o Chronic leukaemia Endeavour College of Natural Health endeavour.edu.au 39

40 Anaemia Anaemia: o Symptoms oxygen-carrying capacity of blood is reduced fatigue, cold intolerance and paleness lack of O2 for ATP and heat production Endeavour College of Natural Health endeavour.edu.au 40

41 Anaemia o Types of anaemia Iron-deficiency = lack of absorption or loss of iron Pernicious = lack of intrinsic factor for B12 absorption Haemorrhagic = loss of RBCs due to bleeding (ulcer) Haemolytic = defects in cell membranes cause rupture Thalassemia = hereditary deficiency of haemoglobin Aplastic = destruction of bone marrow (radiation/toxins) Endeavour College of Natural Health endeavour.edu.au 41

42 Sickle-Cell Anaemia (SCA) Sickle-Cell Anaemia o Genetic defect in haemoglobin molecule (Hb-S) that changes 2 amino acids at low very O2 levels, RBC is deformed by changes in haemoglobin molecule within the RBC sickle-shaped cells rupture easily causing anaemia and clots Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 13th edn, John Wiley & Sons, New York. Endeavour College of Natural Health endeavour.edu.au 42

43 Haemophilia Haemophilia: Inherited deficiency of clotting factors o Symptoms: bleeding spontaneously or after minor trauma subcutaneous and intramuscular haemorrhaging nosebleeds, blood in urine, articular bleeding and pain Endeavour College of Natural Health endeavour.edu.au 43

44 Haemophilia o Types of Haemophilia: Haemophilia A lacks factor VIII (males only) Haemophilia B lacks factor IX (males only) Haemophilia C (males and females) o Treatment is transfusions of fresh plasma or concentrates of the missing clotting factor Endeavour College of Natural Health endeavour.edu.au 44

45 Leukaemia o Acute leukaemia uncontrolled production of immature leukocytes crowding out of normal red bone marrow cells by production of immature WBC prevents production of RBC and platelets o Chronic leukaemia accumulation of mature WBC in bloodstream because they do not die classified by type of WBC that is predominant - monocytic, lymphocytic Endeavour College of Natural Health endeavour.edu.au 45

46 Readings and Resources o Tortora, GJ & Derrickson, B Principles of Anatomy and Physiology, 14th edn, Wiley. o Harris, P, Nagy, S & Vardaxis, N 2010, Mosby s Dictionary of Medicine, Nursing and Health Professions, 2nd edn, Mosby Elsevier. o Guyton, AC & Hall, JE 2011, Textbook of Medical Physiology, 12th edn, Saunders Elsevier. o Marieb, EN & Hoehn, K 2010, Human Anatomy and Physiology, 8th edn, Benjamin Cummings Pearson. o Moore, KL, Dalley, AF & Agur, AMR 2010, Clinically Orientated Anatomy, 6th edn, Lippincott, Williams & Wilkins. Endeavour College of Natural Health endeavour.edu.au 46

47 Copyright COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of the Endeavour College of Natural Health pursuant to Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Endeavour College of Natural Health endeavour.edu.au 47