Blood Vessel Endothelium Function

Questions and Answers

To regulate the entry and exit of materials into and out of the bloodstream

By secreting chemical signals that prevent blood coagulation

Formation of a platelet plug that prevents blood flow out of the vessel

To induce the formation of thrombin Signup and view all the answers

Formation of an adhesive mesh-like structure over the platelet plug Signup and view all the answers

Reduced liver function Signup and view all the answers

Promotion of destruction of clotting factors Signup and view all the answers

To aggregate and form a platelet plug Signup and view all the answers

Study Notes

A single layer of endothelial cells forms the inner wall of all blood vessels, regulating entry and exit of materials into and out of the bloodstream.
Endothelial cells secrete chemical signals that generally prevent blood coagulation (clotting).

Injury to a blood vessel exposes connective tissue (collagen fibers), leading to platelet binding and aggregation, forming a platelet plug (clot).
Platelets and endothelial cells near the damage site release signals that enhance platelet aggregation.
Clotting factors (mainly synthesized in the liver) become activated in response to platelet aggregation, leading to thrombin formation.
Thrombin induces protein strands (fibrin) to form an adhesive mesh-like structure over the platelet plug, reinforcing the clot.

Reduced liver function can decrease clotting factor production, impairing blood clotting.
Reduced platelet production can also impair blood clotting.
Heightened levels of serum antibodies against clotting factors can promote their destruction, impairing clot formation.

Macrophages, phagocytic immune cells, engulf and destroy foreign pathogens and damaged cells.
Macrophages can contribute to clot formation by secreting procoagulant molecules and destroying pathogens entering the body through the cut.