Introduction to Hemostasis I

Question 1

At sites of injury, vasoconstriction is induced by __________.

Answer 1

factors released by endothelial cells

Question 2

List the cofactors of the intrinsic pathway.

Answer 2

HMWK, VIII, and V

Question 3

List the cofactors of the extrinsic pathway.

Answer 3

TF and V

Question 4

Most of the proteases in the coagulation cascade are _______.

Answer 4

serine proteases that exist in the blood as zymogens; they cleave targets at arginine residues

Question 5

The serine-protease pattern holds true except for _______.

Answer 5

factor VIII, which is a transglutaminase (forms a lysine-glutamine bond)

Question 6

What does factor XIIIa do?

Answer 6

It cross links the polymerized fibrin molecules.

Question 7

All of the blood factors are made in the liver, with the exceptions of _________.

Answer 7

von Willebrand factor (found on endothelial cells and platelets), factor VIII (produced by many different organs), and tissue factor (found on the surface of cells)

Question 8

Those with liver disease often have poor _______ absorption, due to _______.

Answer 8

vitamin K; deficient fat absorption

Question 9

Vitamin K (so named for its association with coagulation, because Germans spell coagulation with a K) is necessary for ________.

Answer 9

post-translational modification of coagulation factors

Question 10

Surface contact can initiate the _______ pathway.

Answer 10

intrinsic

Question 11

HMWK is _________.

Answer 11

high molecular weight kininogen

Question 12

The vitamin K-dependent serine proteases are __________.

Answer 12

II, VII, IX, X, and protein C

Question 13

Warfarin is the ________ name, while Coumadin is the ______ name.

Answer 13

generic; brand

Question 14

The only enzyme in the clotting cascade that is not a serine protease is _________.

Answer 14

factor XIII, which is a transglutaminase

Question 15

Cofactors in the clotting cascade are _______.

Answer 15

tissue factor, VIII, V, and HMWK

Question 16

Tissue factor is not normally expressed on __________, but is on ________.

Answer 16

cells in contact with the blood (unless they are under stress or exposed to LPS); fibroblasts and smooth muscle cells

Question 17

Structurally, fibrinogen is composed of _______.

Answer 17

an E unit surrounded by two D units (on either side)

Question 18

vWF is produced and stored in ________; it carries ________.

Answer 18

granules in platelets and endothelial cells; factor VIII

Question 19

Extrinsic tenase is ________.

Answer 19

factor VIIa, tissue factor, and factor X

Question 20

Intrinsic tenase is _________.

Answer 20

factors IXa, VIIIa, and X

Question 21

What three reactions occur on a negatively charged phospholipid in the presence of calcium?

Answer 21

The intrinsic tenase reaction, extrinsic tenase reaction, and the prothrombinase reaction

Question 22

Once prothrombin has been activated to thrombin, thrombin also ___________.

Answer 22

activates V, VIII, XI, and platelets–which amplifies the pathway–and activates XIII

Question 23

XIa activates _________.

Answer 23

more IX

Question 24

There is always some amount of circulating ______, but it does not initiate clotting because ________.

Answer 24

VIIa; it requires tissue factor to become active, which will only be exposed in injured endothelium

Question 25

Factor V is activated by _________.

Answer 25

factors Xa and IIa; Xa then uses factor Va to activate factor II

Question 26

The intrinsic tenase pathway is ________ than the extrinsic pathway.

Answer 26

50 - 100 times faster

Question 27

Prothrombin time tests __________.

Answer 27

the extrinsic pathway

Question 28

APTT is ____________.

Answer 28

the activated partial thromboplastin time; it tests the intrinsic pathway

Question 29

What three things does TF+VIIa activate?

Answer 29

X, IX, and VII

Question 30

IIa amplifies the cascade by _________.

Answer 30

activating more VIIIa, XIa, and Va

Question 31

XIIIa is activated by _________.

Answer 31

factor IIa