Process of hemostasis

Question 1

What happens in the primary stage

Answer 1

platelets interact with damaged endothelium
vessel spasms
formation of platelet plug

Question 2

What happens in the secondary stage

Answer 2

the extrinsic or intrinsic pathways form a fibrin clot

Question 3

What happens in the final stage

Answer 3

clot retraction

Question 4

What mediator is most responsible for vessel spasms

Answer 4

TXA2

Question 5

What happens in platelet plug formation

Answer 5

vWF is released from the damaged tissue, then binds to platelets causing the platelets to bind to the exposed collagen fibers. As they adhere to the collagen they release ADP and TXA2 and activate F4 and 5, which increase platelet aggregation

Question 6

What happens in blood coagulation (second stage)

Answer 6

Intrinsic pathway- 12 activates 11 activating 9 activating 10 with the help of 8(vWF) and Ca2, then 10 and 5 convert prothrombin (F2) into thrombin which converts fibrinogen into fibrin
Extrinsic pathway- TF3 is released from damaged tissue and combines with 7 and Ca2 to activate 10 which combines with 5 to comtinue the same common pathway

Question 7

What effect does thrombin have on the coagulation cascade

Answer 7

accelerating the production of factor 11 8 and 5

Question 8

What happens in clot retraction

Answer 8

after the clot forms the actin and myosin of the platelets contract like muscles do causing the clot to shrink and plasma without fibrinogen to be squeezed out

Question 9

What happens in clot dissolution or lysis

Answer 9

plasminogen is coverted into plasmin by t-PA to dissolve the clot

Question 10

How does the extrinsic path activate the intrinsic path

Answer 10

7 combined with Ca2 activates 9