Physiology of platelets, haemostasias and thrombosis Flashcards
(18 cards)
how are platelets formed
cytoplasm of megakaryocytes
what are lysosomes a type of
vesicles
what are some factors that activate platelets (give 3)
thrombin
thromboxane A2
mechanical stimuli
serotonin
ADP
collagen
what receptor does ADP and thromboxane A2 bind to for platelet function
P2Y1/12
which receptors are the cause for the sticking of platelets
GPIIb and GPIIIa
what is in a alpha granule
growth factors
mitogens
adhesive proteins
what type of adhesive proteins found in alpha granules
fibrinogen, vWF, P-selectin
what is contained in a dense granule
nucleotides: ATP ADP
serotonin
histamine
what is the major ligand for the glycoprotein IIb/IIIa
fibrinogen
what is the adhesive binding site called on platelets
RGD binding site
what is coagulation
the pathway in which thrombin turns soluble and fibrinogen turns insoluble (fibrin)
what does a stable clot require
phospholipid surface
- supplied by activated platelets
what turns fibrinogen to fibrin
thrombin
what turns prothrombin to thrombin
active factor X (10)
what is fibrinolysis
breakdown of clots when it is uneeded
why do clots not break down right after formation
T-PA is bound to the PAI-1, so it does not immediately breakdown clots
what does plasmin do to clots
breaks down clots
what does plasmin do to breakdown clots
degrades fibrinogen
