Coagulation

Question 1

Intrinsic pathway trigger

Answer 1

collagen, contact with a surface (e.g., catheter)

Question 2

Extrinsic pathway trigger

Answer 2

TF

Question 3

Intrinsic pathway factors

Answer 3

12, 11, 9, 8

Question 4

Extrinsic pathway factors

Answer 4

Tissue Factor (3), 7

Question 5

Intrinsic tenase:

Answer 5

FIX, FVIII, PL, Ca2+

Question 6

Extrinsic tenase

Answer 6

TF, FVII, PL, Ca2+

Question 7

Common pathway:

Answer 7

FX, FV,,Thrombin (II), Fibrin (I) - Canadian dollar denominations

Question 8

Prothrombin Activator Complex

Answer 8

FX, FV, Ca2+, PL

Question 9

What thrombin activates

Answer 9

FIX (intrinsic), FVIII (intrinsic), FXIII (fibrin stabilizing factor), FV (prothrombinase complex)

Question 10

What the extrinsic tenase complex activates

Answer 10

FX, FIX (intrinsic pathway)

Question 11

Role of platelets

Answer 11

• provide PL
• provide XIII (fibrin stabilizing factor)
• Provide Ca2+ from ER and golgi apparatus
• bind prothrombin on their surface

Question 12

Vitamin K-dependent Factors

Answer 12

1972:

• FX (common pathway)
• FIX (intrinsic pathway)
• FVII (extrinsic pathway)
• F2 (thrombin - common pathway)

Question 13

What factors does heparin inhibit

Answer 13

Combines with antithrombin:

Intrinsic pathway

• FXII
• FXI
• FIX

and
X (common)

Question 14

What does aPTT test

Answer 14

• intrinsic pathway
  (Table Tennis indoors)
• effects of heparin

Question 15

What does PT/INR test?

Answer 15

• extrinsic pathway
  (Tennis = outdoors)
• effects of warfarin

Question 16

What does antithrombin do?

Answer 16

inhibits

• thrombin (II)
• FX
• Intrinsic pathway
  
  • FIX
  • FXI
• has heparin binding site

Question 17

How do protein C and S work?

Answer 17

Thrombomodulin (TM) on endothelial cell surface binds thrombin

• thrombin can then activates protein C (APC)
• APC + protein S inhibits
  
  • FV (in prothrombinase complex)
  • FVIII (in intrinsic tenase)

Question 18

What is Tissue Factor Pathway Inhibitor? (TFPI)

Answer 18

• in plasma, most bound to endothelial cells
• Inhibits FX
• FX + TFPI inhibits extrinsic pathway (TF/FVII)
• heparin increases TFPI levels in plasma

Question 19

What does a TT or TCT test?

Answer 19

Thrombin time - localizes defect to problem with thrombin or fibrinogen
- used when aPTT and PT/INR are prolonged

Question 20

Virchow’s Triad (prothrombitic factors)

Answer 20

• Stasis: immobility
• Vascular injury: surgery, trauma
• Hypercoagulability: inherited or acquired defect in the cascade