BIO L 460 1st Edition Lecture 22 Outline of Last Lecture I. Lymph VesselsII. Lymph NodesIII. Atherosclerosis IV. Blood Clotting a. Formationb. Anticoagulants Outline of Current Lecture I. Blood Clottinga. Plateletsi. Paracrine Factors b. Hemostasis c. Platelet Release reactioni. Von willebrands factor 1. Thromboxane A2 and ADPd. Formation of Cloti. Coagulation cascade Current LectureBlood Clotting1. Platelets (thrombocytes)- don’t stick together due to: These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Repel because of negative chargeb. Plasma membrane of endothelial cells has a negative chargec. Paracrine factors i. Both function to trigger vasodilation and prevent the platelets from sticking together 1. Prostacyclin2. Nitric Oxided. CD39- enzyme that catalyzes reaction where ADP (makes platelets stick)→ AMP and Pie. Blood is constantly in motion, which prevents blood clot2. Hemostasis – cessation of bleedinga. 3 stepsi. Vasoconstriction- smooth muscle of tunica media contractii. Platelet plug – petechiae (red spots where platelets aren’t being properly produced; capillaries have been torn open)iii. Coagulation cascade→ blood clot 3. Figure 13.7a. Endothelium of intact vessel produces NO (vasodilator) and prostacyclin (a prostaglandin that keeps platelets from sticking together and acts as a vasodilator)b. CD39 – ADPAP + P; ADP allows platelets to stick, so CD39 prevents ADP from building up when clotting is not needed4. Causes Platelet Release Reaction (Possible Essay Question*)a. Damaged Vessel caused by injury b. Rupture in endotheliumi. Platelets come in contact with substances in extracellular matrix 1. collagen2. Platelets have proteins that stick to collagenc. Von Willebrands Factor (VWF, pitchfork structure) – protein produced by endothelial cells, help platelets adhere to collagen (one type of hemophilia caused by a deficiency in this)i. Degranulation (vesicles in platelet look like granules)ii. Vesicles undergo exocytosis, fusing with PMiii. Thromboxane A2 (prostaglandin) and ADP are released1. TXA2 helps platelets stick so they can clot and form the platelet plug; also a vasoconstrictor2. ADP makes platelets sticky3. Growth factors released- important in stimulation of regeneration of connective tissue 4. Tissue Factor released – found in plasma membrane of most cells; important in beginning cascade that can lead to platelet blood clot5. Formation of a Clota. Fibrin – network/mesh of fibers; can contractb. Fibrinogen (soluble plasma proteins) [throbrin] polymer of fibrinc. Prothrombin Thrombind. Serum- everything in plasma minus fibrin e. Clotting Factorsi. Mostly plasma proteins in bloodii. Work together to form clotiii. Ca2+ neededf. Coagulation Cascadei. Intrinsic Pathway1. Slower2. Blood only3. Clots by itselfii. Extrinsic Pathway1. Involves chemicals from tissues2. Tissue Factorsiii. Anticoagulants1. Aspirin inhibits COX-1, inhibits platelet release
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