BSC 1086C Lecture Notes - Lecture 5: Tissue Plasminogen Activator, Vasospasm, Endothelium
Document Summary
Granules contain serotonin, ca2+, enzymes, adp, and platelet-derived growth factor (pdgf) Form a temporary platelet plug that helps seal breaks in blood vessels. Circulating platelets are kept inactive and mobile by no and prostacyclin from endothelial cells of blood vessels. Fast series of reactions for stoppage of bleeding. Vascular spasm: platelet plug formation, coagulation (blood clotting) Triggered by: direct injury, chemical released by endothelial cells and platelets, pain reflexes. Cannot stop the bleeding but will slow down the loss of blood. Positive feedback cycle: platelets stick to exposed collagen fibers at the site of vessel injury, swell, become spiked and sticky, and release chemical messengers. Adp causes more platelets to stick and release their contents. Serotonin and thromboxane a2 enhance vascular spasm and. Platelet plug temporarily plugs damage to the vessel wall more platelet aggregation. A set of reactions in which blood is transformed from a liquid to a gel. Reinforces the platelet plug with fibrin threads.
