Thrombosis Flashcards
What is vasoconstriction?
Brief, local reduction in blood flow. Endothelium is damaged and releases endothelin causing vasoconstriction
Primary haemostasis
Sub enodthelial structures exposed, produced VWF, binds to collagen. Platelets GP1B surface proteins bind to vWF on collagen. Positive feedback loop.
Platelets change shape, release more vWF and thromboxane A2 which leads to GP11B/IIIA expression. What does GP11B/IIIA bind to?
Fibrinogen, linking platelets to make a platelet plug
What is a key enzyme that act wihtin amplification system
Thrombin
extrinsic pathway activated by tissue factor _ when tissue factors is exposed to blood
7
The intrinsic pathway begins when factor __ is exposed to collaged which is activated by factors in the blood
12
What is the common pathwya of the coagulation cascade?
Factors X, V, II, I, XIII which ultimately converts fibrinogen to fibrin
Where are almost all the coagulation factors and inhibitors synthesised?
Liver
Factor 12 contacts negatively charged phosphates on platelets and subendothelial c_______ 12a
collagen
12a cleaves factor 11 into factor ___
11a
11a (+ Ca) cleaves factor 9 into __
9a
9a + 8a (binds to vWF) and c____ and enters the common pathway
calcium
10 is cleaved to __
10a
Xa 10a cleaves factor _ into factor __
5 to 5a
Factor 10a + 5a + calcium forms a p_____________ complex
prothrombinase
Prothrombin (2) is cleaved to t_____ (2a)
thrombin
Thrombin activates platelets, cofactors (V, VIII, IX); cleaves f______ , stabilisizing factor (13a + calcium = cross links in mesh)
fibrinogen
True or false, thrombin activates platelets
True
True of false, thrombin ensures clot stabilisation by activating factor 13?
True
PT is the measure of time taken for the blood to c___ via the extrinsic pathway
clot
APPT is the measure of time taken for the blood to clot via the _______ pathway
intrinsic
TT is the time taken for f______ to convert to f____
fibrinogen, fibrin (thrombin)
Plasminogen activators are released from endothelial cells which cleave plasminogen to plasmin which rapidly digest the f_____ c____
fibrin clot
