PSL301H1 Lecture Notes - Lecture 5: Von Willebrand Factor, Endothelium, Megakaryocyte

• School: UTSG
• Department: Physiology
• Course: PSL301H1
• Professor: Michelle French

Document Summary

Cytokine: a molecule secreted by certain cells of the immune system that have an effect on other cells. Megakaryocytes: made by a fusion of cells. Half life of thrombocytes = 10 days. Thrombopoietin increases platelet production: a cytokine, vascular phase (vasoconstriction, platelet aggregation phase (platelet form loose plug, coagulation phase (reinforced platelet plug) Effect: smooth muscle constriction vasoconstriction: to decrease blood loss. Initial control neurogenic & myogenic (short: controlled by neurons & myocytes, vasoconstriction prolonged, serotonin, endothelin-1, thromboxane a2. Trigger: collagen exposure from blood vessel damage: rbc float in middle of blood vessel, platelets skim along endothelial cells of blood vessels surveillance. Effect: collagen activates platelets, von willebrand factor: crosslinks platelet & collagen, made by endothelial cells & platelets, platelets bind to wound at injury site & release factors attract more platelets, platelets release: adp, platelet activating factor (paf), Serotonin & thromboxane a2: serotonin & thromboxane a2 also cause, platelets aggregate form temporary, loose plug vasoconstriction.