hemostasis

Question 1

process which causes bleeding to stop

Answer 1

hemostasis

Question 2

what is the goal of hemostasis

Answer 2

keep blood within a damaged blood vessel

Question 3

the opposite of hemostasis is ?

Answer 3

hemorrhage

Question 4

4 phases of hemostatic process

Answer 4

1. create platelet plug
2. propagation of clotting process by the coagulation cascade
3. termination of clotting by antithrombotic control mechanisms
4. removal of the clot by fibrinolysis

Question 5

what are the 3 hemostatic system players

Answer 5

1. blood proteins
   - procoagulant factors
   - anticoagulant factors
2. platelets
3. vessel wall
   - procoagulant factors
   -anticoagulant factors

Question 6

endogenous PLTs circulate for how long before being cleared from circulation?

Answer 6

~10 d

Question 7

PLTs promote clotting in 2 ways:

Answer 7

1. at site of active bleed, PLTs bind to exposed collagen to form primary plug (first response)
2. after plug is formed, more PLTs come to expand and propagate the clot

Question 8

secretion and granule content release and causes what? (3)

Answer 8

active coagulation
vasoconstriction
promote wound healing

Question 9

von willebrand factor is synthesized and stored in: (2)

Answer 9

1. endothelial cells
2. PLTs

Question 10

primary function of von willebrand factor

Answer 10

binding to other proteins
(does not require a catalytic event bc not an enzyme)

Question 11

3 coagulation functions of von willebrand factor

Answer 11

1. binds to endothelium and promotes and PLT adhesion to sites of vessel (through platelet glycoprotein Ib)
2. plasma carrier for factor VIII, prevents its degradation
3. binds to collagen when exposed

Question 12

factor VIII is released from ___ by ____

Answer 12

vWF
thrombin

Question 13

which hemostasis pathway is activated by tissue factor found outside the blood

Answer 13

extrinsic

Question 14

which hemostasis pathway has factors required for activation found in the blood

Answer 14

intrinsic

Question 15

all hemostasis pathways lead to ?

Answer 15

common pathway - activation of factor X

Question 16

what are the 3 essential steps of blood coagulation

Answer 16

1. prothrombin activator formed
2. prothrombin activator causes conversion of prothrombin to thrombin
3. thrombin converts fibrinogen to fibrin

Question 17

what are the 2 ways to form prothrombin factor

Answer 17

extrinsic pathway
intrinsic pathway

Question 18

most coagulation factors are synthesized in the ?

Answer 18

liver

Question 19

what coagulation factors require vitamin K (6)

Answer 19

II, VII, IX, X, protein C, protein S

Question 20

levels of vitamin K go down in: (3)

Answer 20

1. fat malabsorption/malnutrition
2. antibiotic therapy (esp. cephalosporin)
3. newborn

Question 21

what is a vitamin K antagonist

Answer 21

warfarin (coumadin)

Question 22

3 steps of extrinsic pathway

Answer 22

1. release of tissue thromboplastin from traumatized tissue
2. activation of factor VII (VIIa)
3. activation of factor X (Xa) = prothrombin activator (common pathway)

Question 23

5 steps of intrinsic pathway

Answer 23

1. exposure to collagen causes activation of factor XII (XIIa)
2. causes activation of factor XI (XIa)
3. causes activation of factor IX (IXa) with help of Calcium
4. IXa, VIIIa, calcium = complex = activates factor X
5. activation of factor X = prothrombin activator

Question 24

prothrombin is produced continuously in ?

Answer 24

liver

Question 25

lack of vit K or presence of liver disease prevents ?

Answer 25

normal prothrombin formation

Question 26

fibrinogen is a protein formed in the

Answer 26

liver

Question 27

what converts fibrinogen into fibrin

Answer 27

thrombin

Question 28

what is the most abundant coagulation protein

Answer 28

fibrin (factor I)

Question 29

what stabilizes the fibrin after its been converted

Answer 29

factor XIIIa

Question 30

what protein predominantly synthesized in the liver

Answer 30

glycoprotein

Question 31

when activated, these proteins have almost a direct effect on conversion of prothrombin to thrombin

Answer 31

protein C and S

Question 32

anti-thrombin (III) inactivates what?

Answer 32

thrombin, IXa, Xa, XIa, and XIIa

Question 33

4 anticoagulant plasma proteins

Answer 33

1. protein C and S 2. anti-thrombin (III) 3. tissue factor pathway inhibitor 4. fibrinolysis system

Question 34

what is the function of the activated protein c

Answer 34

inhibition of factors Va and VIIIa

Question 35

what is the function of tPA

Answer 35

conversion of plasminogen to plasmin