thrombosis Flashcards
what is thrombosis
formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system.
what lines the lumen
endothelial cells
what are surrounds the basal lamina
smooth muscle
what surrounds the smooth muscle
interstitial collagen fibres
what does lumen contain?
red blood cells, white blood cells. platalets, plasma
are platalets normally exposed to interstitial collagen fibres around the vessel
no
what does plasma consist of
water and numerous protiens and other molecules
what kind of factors does plasma contain?
clotting factors
what is plasma without the clotting factors?
serum
where are clotting factors produced
liver, endothelial cells
what does thrombonin convert …. into ….
soluble fibronogen into insoluble fibrin
what kind of system is the clotting cascade
amplification system
what is the initial damage
trauma leads to exposed interstitial collagens and exposure of tissue factor
what does trauma lead to in vessels
defects
what happens when there is a defect in the vessel?
blood leaks out and serum comes into contact with the interstitial collagen fibres
how are clotting factors activated?
when they come in contact with the collagen fibres
what is the function of tissue factor when there has been defects in the vessel
bind a clotting factor and initiate the clotting cascade
why is it important that clotting factors are serine proteases
they have a serine amino acid in them and they cleave other clotting factors to form the active molecule
what is formed into thrombonin
prothrombin
what is the endpoint of clotting cascade
production of insoluble fibrin strands that form meshwork
where are platalets produced?
bone marrow
what is megakaryocyte
large cell with many nuclei
can megakaryocytes undergo cell division?
no
what is platalets role when there is a defect in the vessel
platalets try form a bridge to close the gap
what is coagulation
solidification of blood
what are the two types of coagulation
thrombosis formation and clot formation
what kind of coagulation is formed in flowing blood
thrombosis
why does thrombosis occur in flowing blood
Platelets have molecules on their surfaces which allow adherence to interstitial collagen, even when blood is flowing past them – the clotting cascade deposits Factor VIII which enhances this further
how would you describe a blood clot formation
blood leaks out off a vessel and becomes stationary
what does a clot consist of
network of fibrin strands and red blood cells
how is haemostasis achieved?
vessel vasoconstrics and platalets form bridge
what is granulation tissue?
new vessels formed around an area of wound
what is ischaemia
lack of blood flow to tissue
how is excess thrombosis or clot removed?
In blood there is a fibrinolytic system which removes fibrin and stops thrombi from propagating
what does the fibronolytic system depend on?
plasma protein called plasminogen being converted to plasmin
what does plasmin cut fibrin into?
fibrin degradation products
what are the three things associated with abnormal thrombosis and clotting
Abnormalities of vessel wall
Abnormalities of constituents of the blood
Abnormalities of vessel flow
whats haemostasis
the stopping of bleeding
what is thrombi
platalets admixed w fibrin and form in flowing blood
