Chapter 14: Blood Coagulation Process

Question 1

What happens in Phase I of blood coagulation?

Answer 1

Thromboplastin forms

Question 2

What two types of factors can cause thromboplastin to form?

Answer 2

1) Intrinsic factors within the blood (platelet phospholipids and plasma factors)
2) Extrinsic factors from components outside the circulatory system released from damaged tissues

Question 3

True or false: Both the intrinsic and extrinsic factors may be activated at the same time.

Answer 3

True

Question 4

Which pathway for thromboplastin formation (extrinsic or intrinsic) is more important to initiate blood clotting?

Answer 4

Extrinsic

Question 5

What happens in phase II of blood clotting?

Answer 5

Conversion of prothrombin into thrombin (catalyzed by thromboplastin)

Question 6

What is thromboplastin?

Answer 6

The enzyme that catalyzes the conversion of prothrombin (proT) into thrombin (T).

Question 7

What enzyme catalyzes the conversion of prothrombin (proT) into thrombin (T)?

Answer 7

Thromboplastin

Question 8

What is the is the thromboplastin activator complex (thromboplastin combined with factors)?

Answer 8

prothrombinase

Question 9

What happens in the third phase of blood coagulation?

Answer 9

Conversion of fibrinogen into fibrin by thrombin and formation of a fibrin clot

Question 10

How does thrombin convert fibrinogen into fibrin?

Answer 10

It splits off pieces of fibrinogen and forms smaller fibrin monomers. These monomers polymerize into long fibrin strands and are x-linked side to side.

Question 11

What factor strengthens the bonds between fibrin molecules to increase the strength of the clot?

Answer 11

Fibrin stabilizing factor

Question 12

End stage of clotting process; consists of
an interlaced meshwork of fibrin threads with
entrapped plasma, red cells, white cells, and platelets.

Answer 12

Blood clot

Question 13

What does a blood clot consist of?

Answer 13

Meshwork of fibrin threads with entrapped plasma, RBCs, WBCs, and platelets.

Question 14

Steps of Blood Coagulation

Answer 14

1) Phase I: Activation of thromboplastin by either intrinsic (platelets and plasma factors) or extrinsic (tissue injury) pathways
2) Phase II: Conversion of prothrombin into thrombin by prothrombinase.
3) Phase III: Conversion of fibrinogen into fibrin by thrombin and formation of fibrin clot (made of fibrin meshwork, blood cells, and plasma).