Biochem Coagulation

Question 1

Coagulation factors

Source: plasma and platelets

Answer 1

I (fibrinogen)
IV (Ca)
XIII
vWF

Question 2

Coagulation factors

Source: plasma only

Answer 2

II (Prothrombin)
VII-XII
Prekallikrein
HMWK

Question 3

Coagulation factors

Source: sub endothelial tissues

Answer 3

III (tissue factor)

Question 4

Coagulation factors

Vitamin K

Answer 4

II (Prothrombin)
VII
IX
x

Question 5

How do endothelial cells inhibit blood clotting?

Answer 5

Heparan sulfate proteoglycans
Prostacyclin (PGI2)
Thrombomodulin
tPA

Question 6

What are the most abundant receptors on the platelet surface?

Answer 6

GPIIb/IIIa

Question 7

Coagulation is initiated by the extrinsic pathway when ___. Then what happens?

Answer 7

Tissue factor is exposed to plasma

• tissue factor binds to FVII only in the presence of Ca
• FVII is further activated by FXa or thrombin
• the tissue factor-FVIIa-Ca complex activates FX to FXa and FIX to FIXa

Question 8

___ has a long half life in circulation, but it is not active unless bound to tissue factor

Answer 8

FVIIa

Question 9

Formation of ___ is the first step in the final common pathway

Answer 9

FX –> FXa

* activated by the X-ase complex (which includes tissue factor, FVIIa, and Ca)

Question 10

FXa forms a platelet membrane-bound complex with___. This activates what?

Answer 10

FV

Prothrombin –> thrombin

Question 11

___ converts fibrinogen to fibrin monomers.

What else does it do?

Answer 11

Thrombin

• activates FVIII, FXI of the intrinsic pathway
• activates FV and FXIII of the common final pathway
• activates FVII of the extrinsic pathway

Question 12

Intrinsic pathway:

Answer 12

1. FXII binds to anionic surfaces
2. Prekallikrein and FXI interact with HMWK and are brought close to FXII
3. FXII activates prekallikrein to kallikrein which then activates FXII to FXIIa
4. FXIIa activates FXI to FXIa
5. FXIa activates FIX to FIXa
6. FIXa and FVIIIa activate FX to FXa.
7. FVIII circulates bound to vWF, which protects FVIII from destruction

Question 13

Factors involved in anti coagulation:

Source: plasma

Answer 13

Antithrombin (III)
Protein C
Protein S
TFPI
Other Serpins

Question 14

Factors involved in anti coagulation:

Source: endothelial cells

Answer 14

Thrombomodulin

NO

Question 15

Factors involved in anti coagulation:

Vitamin K

Answer 15

Protein C

Protein S

Question 16

Where is antithrombin synthesized?

What does it inactivate?

Answer 16

Liver

Thrombin, FIXa, FXa, FXIa, FXIIa

Question 17

The activity of antithrombin is enhanced by what?

Answer 17

Glucosaminoglycans such as heparin and heparan sulfate

Question 18

TFPI does what?

Answer 18

Inactivates tissue factor-FVIIa-Ca complex

Question 19

Proteins and factors involved in fibrinolysis:
Source?
Synthesis of each?

Answer 19

All found in plasma

1. Plasminogen-liver
2. tPA (Tissue plasminogen activator)-endothelial cells
3. uPA (Urokinase, urinary plasminogen activator)-kidney
4. Streptokinase- beta hemolytic strep
5. PAI-1 (plasminogen activator inhibitor 1)- endothelial cells, liver
6. a2-antiplasmin- liver

Question 20

all of the vitamin K dependent factors require ___

Answer 20

Ca binding

*so all contain gamma-carboxyglutamyl residues

Question 21

Hemophilia is due to ___

Answer 21

Deficiency in:
FVIII (hemophilia a)
or FIX (hemophilia b)

Question 22

Bernard soulier disease is due to __

Symptoms are similar to __

Answer 22

Deficiency in GPIb/IX/V

*von Willebrand disease