PHYSIOL 1 Lecture Notes - Lecture 24: Collagen, Pulmonary Artery, Coagulation
Document Summary
When vessel is damaged, exposure of blood to subendothelial tissue (collagen) leads to 3 responses. Platelets bind to exposed collagen, leading to platelet activation. This leads to release of chemical mediators (thromboxane) Also causes vasoconstrictions (sticking together of platelets) Platelet plug can seal small breaks in vessels. Coagulation of blood around the platelet plug is the dominant hemostatic defense. Clotting involves a complex chemical cascade initiated by exposure of blood to collagen. Thrombin is produced at end of cascade and has 3 roles. Activate factor 13, which stabilized fibrin mesh. Consists of 2 interconnected circuits, both originating and terminating in the heart. Circuits always begin in the pumping chambers (ventricles- bottom of heart) Circuits end in the receiving chambers (atria- top of heart) Pumps deoxygenated blood from the right ventricle to the lungs. Pumps oxygenated blood from left ventricle to systemic capillaries. Flow through the 2 circuits must be identical. Arteries carry blood away from the heart.
