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Blood Clotting. Serum + blood clot gel Fibrin traps formed elements Coagulation Thrombosis Embolus. Blood Clotting. Chemicals involved: Ca 2+ Inactive enzymes Molecules from platelets Molecules from damaged tissues Requires Vitamin K and Ca 2+ Uncontrolled bleeding. Blood Clotting.
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Blood Clotting • Serum + blood clot gel • Fibrin traps formed elements • Coagulation • Thrombosis • Embolus
Blood Clotting • Chemicals involved: • Ca2+ • Inactive enzymes • Molecules from platelets • Molecules from damaged tissues • Requires Vitamin K and Ca2+ • Uncontrolled bleeding
Blood Clotting • Formation of prothrombinase • Via 2 pathways • Conversion of prothrombin into thrombin by prothrombinase • Conversion of fibrinogen into fibrin by thrombin
Prothrombinase Formation • TF = thromboplastin (lipoproteins + phospholipids) • Clotting factor X = thrombokinase • Factor V = proaccelerin • Factor XII = Hagemen factor
Fibrin Formation • Factor XIII = fibrin-stabilizing factor • (also in plasma + platelets)
Positive Feedback of Thrombin • Accelerates prothrombinase formation (clotting factor V) • Activates platelets = reinforces aggregation
Clot Retraction • “Shrinking” of a blood clot • Platelets pull on fibrin threads = contract vessel • Permanent repair of the blood vessel • Fibroblasts form CT in ruptured area • New endothelial cells repair vessel lining • Fibrinolytic mechanisms break down clot
Quick assigned reading • Read “Homeostatic Control Mechanisms” page 679-680
Blood Topics • Functions and Properties of Blood • Components of Blood • Blood Cell Formation • Red Blood Cells • White Blood Cells • Platelets • Hemostasis • Blood Groups and Blood Transfusion
Blood Groups • The ABO blood types and Rh system are based on antigen-antibody responses • 24 blood groups • 100 antigens
Blood Groups • “Self-antigens” are located on RBC plasma membranes • Blood grouping based on presence/absence of self-antigens
ABO Cross Matching Donor Recipient
Rh Group • Rh+ = expression of Rh antigen • Rh- = no expression of Rh antigen • Most people are Rh+ • Most people do not have Anti-Rh antibodies. • If an Rh- person is exposed to Rh+ blood, they will produce Anti-Rh antibodies.
Donations • Universal donor = O- • Universal receiver = AB+ • These terms are dangerous! • Cross-matching
Blood Transfusion • Principles of Transfusion • Hemolysis occurs if recipient’s blood plasma antibodies interact with donor’s antigens
Key Terms • Agglutinins = antibodies • Agglutinogens = antigens • Incompatibility between them = aggluntination
Review Questions • What are the functions of the cardiovascular system? • Rapidly transports nutrients, respiratory gases, regulatory substances, waste products, and cells within the body. • What are the main components of the cardiovascular system? • Blood, Heart, Blood Vessels • What are the main components of blood? • Plasma – mostly water • Formed elements – RBCs, WBCs, platelets
Review Questions 4. Where are blood cells manufactured? • Red bone marrow 5. Name three kinds of hemopoietic growth factors. • Erythopoietin (EPO) • Thrombopoietin • Cytokines 6. What are the main functions of a RBC? • Transport oxygen bound to hemoglobin
Review Questions 7. What is erythropoiesis? • Formation of RBC from pluripotent stem cells myeloid stem cells 8. Which parts of hemoglobin are recycled and reused? • Amino acids protein synthesis • Iron (Fe3+) stored / used for new RBC formation 9. Which WBCs are agranular? • Lymphocytes and monocytes 10. Which WBC is normally the most prevalent? • Neutrophils
Review Questions 11. List three platelet functions • Form platelet plug • Promote vascular spasm • Promote blood clotting (cascade) 12. What are the three steps of hemostasis? • Vascular spasm • Platelet plug formation • Blood clotting
Review Questions 13. What are the three main steps of blood clotting? • Formation of prothrombinase • Conversion of prothrombin into thrombin by prothrombinase • Conversion of fibrinogen into fibrin by thrombin 14. Which antigen(s) and antibody(s) are found in type A blood? • Antigen A • Antibody anti-B