7. Haemostasis Flashcards
importance of haemostasis
important survival mech to minimise blood loss after injury
5 main components of haemostasis
- blood vessels
- platelets
- coagulation factors
- coagulation inhibitors
- fibrinolysis
2 forms of haemostatic plug
primary plug
stable plug (w/fibrin crosslinks)
endothelial cell effects of haemostasis
- inhibit = release prostacyclin and nitric oxide
- promote = source of vwf and tPA
initial reflex to minimise blood loos
vsaoconstriciton of smooth muscle cells
= until other mechanisms take overq
what are platelets
fragmentations of megakaryocyte cytoplasm
(1 megakaryo = 4000 platelts0
size of platelets
2-4 micrometers
lifespan of platelet
9-10days
nromal platelet count
150-400 x10^$
where are platelets destroyed and by which cells
spleen and liver
as per usual
by
Kupffer cells
process of making platelets name
endomitotic synchronous nuclear replication
3 things that control platelet production
- neg feedback from number of circ platelets
- stim by thrombopoietin
- IL-3 and GM-CSF = general growth factors
what is glycocalyx and what is it primarily composed of
outer layer of cell
glycoproteins
which glycoproteins are in platelet glycocalyx
GPIa
GPIb
GPIIb
function of platelet glycocalyx
when collagen exposed
glycoproteins allow platelet to adgere onto area of damage
