Hemostasis

Question 1

What are the 3 steps of normal hemostasis?

Answer 1

• Vasoconstriction
• Platelet aggregation
• Fibrin formation

Question 2

What platelet antigen is the receptor for collagen?

Answer 2

GPIa/IIa complex

Question 3

What platelet antigen is the receptor for vWF?

Answer 3

GPIb

Question 4

How is GPIb activated (in vivo/in vitro)?

Answer 4

• Shear forces (in vivo)

- Ristocetin (in vitro)

Question 5

Platelet degranulation leads to release of what?

Answer 5

• alpha and dense granules

- Thromboxane A2 (TXA2)

Question 6

What do platelet Alpha granules contain? (5)

Answer 6

Large molecules:

• fibrinogen
• PDGF
• vWF
• P-selectin
• Platelet Factor 4 (PF4)

Question 7

What do platelet Dense granules contain? (4)

Answer 7

Small molecules:

• ADP
• ATP
• 5-HT
• Calcium

Question 8

What stimulates platelet degranulation? (6)

Answer 8

Platelet Agonists:

• Epinephrine
• ADP
• Thrombin
• Platelet Activating Factor
• Collagen
• TXA2

Question 9

What mediates platelet aggregation? (2)

Answer 9

• GPIIb/IIIa

- Fibrinogen

Question 10

Factors in Intrinsic Pathway.

Answer 10

• Factors 12,11,9,8

- prekallikrein & HMWK

Question 11

Which factor links Intrinsic and Extrinsic Pathways?

Answer 11

Factor 10a

-F7 to F7a

Question 12

What is the only factor unique to the Extrinsic pathway?

Answer 12

-F7

Question 13

What initiates Extrinsic Pathway in vitro?

Answer 13

Tissue Factor (Factor 3)

Question 14

What does activated factor 7 (F7a) do?

Answer 14

Cleaves F10 to F10a

F7a is the “tenase” of the Extrinsic Pathway

Question 15

What are the constituents of the Common Pathway?

Answer 15

• F10
• Prothrombin (F2)
• Fibrinogen (F1)

Question 16

What initiates the Common Pathway?

Answer 16

Activation of F10 to F10a

Question 17

What does F10a do?

Answer 17

Converts F2 to F2a (thrombin)

Question 18

What platelet cell surface antigen is the receptor for vWF?

Answer 18

GpIb/V/IX complex (CD42)

Question 19

What Red Cell antigens are also on platelet cell surface? (5)

Answer 19

• ABO
• P
• I/i
• Le

*NO Rh antigens

Question 20

Which MHC class antigens are present on platelet cell surface?

Answer 20

MHC Class I

Question 21

Which clotting factor has the shortest T1/2?

Answer 21

Factor 7 (FVII)
-6 hours

Question 22

Vitamin K dependent coagulation factors. (4)

Answer 22

-2,7,9,10 (II,VII,IX,X)