BIOL 221 Lecture Notes - Lecture 1: Vasospasm, Endothelium, Prostacyclin
10 Feb 2020
School
Department
Course
Professor
Document Summary
Platelet chemicals: enhance clotting, stimulate platelet aggregation, stimulate vascular spasm, stimulate vessel repair. Platelets release chemicals that: enhance clotting (protein clotting factors and calcium ions [clotting factor. Iv]): stimulate platelet aggregation (adp and thromboxane a2), stimulate vascular spasm (thromboxane a2 & serotonin); and, stimulate vessel repair by stimulating division of fibroblasts and smooth muscle cells (platelet-derived growth factor, pdgf). Natural limits to platelet plug formation: prostacyclin (pgi2; local prostaglandin, secreted by endothelial cells, inhibits platelet aggregation, inhibiting compounds secreted by wbcs. Platelet plug formation is limited by prostacyclin and inhibiting compounds secreted by leukocytes. Prostacyclin (pgi2) is a locally-acting prostaglandin (paracrine compound derived from fatty acids) secreted by endothelial cells. Coagulation phase: forms insoluble fibrin fibers, cascades, positive feedback loop. Coagulation forms insoluble fibrin fibers from the water-soluble plasma protein fibrinogen. The reactions occur as cascades in which each reaction causes many molecules to be formed for subsequent reactions.
