Haemeostasis Flashcards
(20 cards)
What do chemicals do endothelial cells secrete to prevent coagulation?
Nitric oxide
PGI2
What do nitric oxide and PGI2 do?
Inhibit platelets
Keeps inactive
Prevent from binding to endothelial layer
What glycosaminoglycan are present on the endothelial cell to prevent coagulation?
Heparin sulphate
What does heparin sulphate do?
Binds to antithrombin 3
What does antithrombin 3 do?
Inactivates CF II, IX , X
What protein is present on endothelial cells to prevent coagulation?
Thrombomodulin
What does thrombomodulin do?
Binds to thrombin (CF II)
What does thrombin do?
When protein C moves across it it becomes activated
What does activated protein C do?
Degrades CF V, VIII
What do injured endothelial cells secrete?
Endothelin
What does endothelin do?
Binds to receptors on smooth muscle cells and causes smooth muscle contraction —> vascular spasm
What happens when there is a direct injury to the smooth muscle?
Activation of myogenic mechanism
What does the myogenic mechanism cause?
Muscle contraction —> vascular spasm
What do inflammatory chemicals stimulate in order to cause vascular spasms?
Noicocepto activation
For platelet plug formation what do endothelial cells produce?
VWF
How do platelets bind to VWF?
Glycoprotein 1b (Gp1b) on platelet binds to VWF
What happens when platelets bind to VWF?
Platelets start secreting chemicals
What chemicals do platelets secrete?
ADP
Thromboxane A2
Serotonin
What do ADP and thromboxane A2 do?
Stimulate platelets in circulation —> causes them to aggregate and form a plug
How do platelets bind to each other?
Platelets have protein GpIIB/IIIa which have fibrinogen between them —> link platelets together
