Day 4: Blood clotting

Question 1

Blood vessel injury is followed immediately by (1)___ then (2)_____, (3)______, and (4)

Answer 1

vasoconstriction
platelet plug formation
blood coagulation
control clotting

Question 2

Immediate local vasoconstriction results from ________

Answer 2

myogenic contraction

Question 3

In a very severe injury, ________ occurs as well as a myogenic contraction

Answer 3

neurogenic vasospasm

Question 4

neurogenic and myogenic constrictions last how long

Answer 4

20-30 mins

Question 5

what are humoral responses that cause vasoconstriction

Answer 5

serotonin, thromboxane A2, prostaglandins

Question 6

how long do the humorally mediated vasoconstrictions last?

Answer 6

several hours

Question 7

what is platelet adhesion vs platelet aggregation

Answer 7

binding of platelets to surfaces other than other platelets and endothelium.
platelet binds platelet

Question 8

what are the two functions of Von Willebrand Factor

Answer 8

(1) mediates platelet adhesion

(2) maintain function of Clotting Factor VIII

Question 9

What is release reaction?

Answer 9

After the binding of VWF/collagen/thrombin etc the platelet goes through release reaction where it keeps changing its shape and releases serontonin, ADP, Ca2+ etc

Question 10

describe the relationship between ADP concentrations and platelets

Answer 10

At slightly high [ADP] platelets swell, and membrane bound with fibrinogen, begins to clump
If the [ADP] doesn’t continue to increase, the ADP is destroyed and platelets disaggregate. However if [ADP] reaches critical concentration, platelets release endogenous ADP and accelerates platelet aggregation

Question 11

apart from being a vasoconstrictor, Thromboxane A2 is a _______

Answer 11

platelet aggregator

Question 12

whats the action of Prostacyclin (PGI2)

Answer 12

an inhibitor of platelet activation

makes sure that platelet activation and aggregation stays at points of injury

Question 13

How does Aspirin affect clotting?

Answer 13

Aspirin INACTIVATES cyclooxygenase, which is needed for Thromboxane A2 (a platelet aggregator)

Question 14

what is primary hemostasis

Answer 14

vasoconstriction and platelet plugging

Question 15

what is hemophilia?

Answer 15

a sex-linked disorder of clotting Factor XIII

a problem with secondary hemostasis (blood coagulation)

Question 16

How does coumarin work?

Answer 16

blocks the carboxylation of Gamme-carboxyglutamic acid residues on clotting factors, which is needed for the clotting factors to interact with Calcium

Question 17

what is the role of Vitamin K in clotting

Answer 17

required for carboxylation of Gamma-carboxyglutamic acid residues on clotting factors for the clotting factors to interact with calcium

Question 18

platelet pseudopod contraction causes clot retraction which is mediated by ______

Answer 18

actomysin

Question 19

How does Heparin work

Answer 19

it enhances the activity of Antithrombin, which inhibits thrombin and the Factors thrombin activates

Question 20

what is the function of protein C

Answer 20

it is activated when thrombin binds thrombomodulin receptors. Protein C with protein S inhibits Factors V and VIII

Question 21

How do plasmin/ plasminogen work in clotting

Answer 21

plasminogen is an inactive form of plasmin and gets incorporated into the clot. plasminogen activators cause plasminogen to become plasmin and the plasmin degrades fibrin and fibrinogen

Question 22

name a plasmin activator

name a plasmin inactivator/plasminogen activator

Answer 22

tPA

PAI, antiplasmin

Question 23

_____ derives from the plasminogen molecule

Answer 23

angiostatin