Clotting Cascade

Question 1

Hemostasis

Answer 1

Clotting to stop blood flow

Question 2

What occurs with primary hemostasis?

Answer 2

Platelets aggregate at injury site to form a platelet plug and block the hole

Question 3

What is formed with primary hemostasis?

Answer 3

Platelet plug at injury site

Question 4

What occurs with secondary hemostasis?

Answer 4

The platelet plug is further reinforced by a fibrin mesh produced from the coagulation cascade

Question 5

What is formed with secondary hemostasis?

Answer 5

Fibrin mesh over the platelet plug to reinforce it

Question 6

What are the 2 pathway options for secondary hemostasis?

Answer 6

Extrinsic pathway

Intrinsic pathway

Question 7

What activates the extrinsic pathway for secondary hemostasis?

Answer 7

External trauma - blood escapes vascular system

Question 8

Which pathway for secondary hemostasis is quickest?

Answer 8

Extrinsic

Question 9

What is the main factor in the extrinsic pathway for secondary hemostasis?

Answer 9

Factor VII

Question 10

Describe the extrinsic pathway

Answer 10

Factor VII + Tissue factor = VIIa (activated form)

- Then goes to common pathway

Question 11

What activates the intrinsic pathway for secondary hemostasis?

Answer 11

Trauma inside the vascular system;

platelets, chemicals, collagen

Question 12

Which pathway for secondary hemostasis is slowest?

Answer 12

Intrinsic

Question 13

What are the main factors involved in the intrinsic pathway for secondary hemostasis?

Answer 13

Factors XII, XI, IX, VIII

Question 14

Describe the intrinsic pathway

Answer 14

Prokallikrein activates Factor XII –> XIIa
XIIa activates XI –> XIa
XIa activates IX –> IXa
- Activated Factor VIII and IX then go to common pathway

Question 15

What is the common pathway?

Answer 15

Where the extrinsic and intrinsic pathways meet and finish the clot production

Question 16

What factors activate the common pathway for secondary hemostasis?

Answer 16

Factors VII, VIII, IX

Question 17

For the common pathway, factors VII, VIII, IX activate which factors?

Answer 17

X and V

Question 18

For the common pathway, factors X and V then activate which factor?

Answer 18

II (thrombin)

Question 19

Factor II

Answer 19

Thrombin

Question 20

What does Factor II (thrombin) activate?

Answer 20

1. Takes Fibrinogen –> Fibrin

2. Activates Factor XIII

Question 21

What takes Fibrin –> Cross-linked fibrin mesh?

Answer 21

Factor XIII

Question 22

What are the major actions of thrombin?

Answer 22

• Creates Fibrin
• Activation of Factor XIII
• Activation of platelets
• Creates more thrombin

Question 23

Describe the common pathway for secondary hemostasis?

Answer 23

Factor VII (extrinsic) and Factors VIII and IX (intrinsic)

• activate Factors X and V
• X and V activate Factor II
• Factor II takes Fibrinogen to Fibrin
• Factor II activates Factor XIII
• XIII takes Fibrin to Cross-linked Fibrin Mesh!

Question 24

Is primary or secondary hemostasis quicker?

Answer 24

Primary

Question 25

Where is Vitamin K activated?

Answer 25

Liver

Question 26

What enzyme is involved in the first step of Vitamin K activation?

Answer 26

Vitamin K 2,3-epoxide reductase

Question 27

What is the first step in Vitamin K activation?

Answer 27

Vitamin K 2,3-epoxide is converted (using Vitamin K 2,3-epoxide reductase enzyme) to Vitamin K Quinone

Question 28

What enzyme is involved in the second step of vitamin K activation?

Answer 28

Vitamin K quinone reductase

Question 29

What is the second step in Vitamin K activation?

Answer 29

Vitamin K Quinone is converted (using Vitamin K quinone reductase enzyme) to Vitamin K Quinol

Question 30

What is the active form of Vitamin K?

Answer 30

Vitamin K Quinol

Question 31

What factors and proteins are activated by Vitamin K Quinol?

Answer 31

Factors II, VII, IX, X | Proteins S and C

Question 32

Carboxylation of Vitamin K Quinol helps to activate the factors and then converts Vitamin K Quinol to?

Answer 32

Vitamin K 2,3-epoxide

Question 33

What factors and proteins are activated by Vitamin K Quinol?

Answer 33

Factors II, VII, IX, X | Proteins S and C

Question 34

What is the mechanism of action of anticoagulants?

Answer 34

Vitamin K INHIBITION

Question 35

What are the 2 types of anticoagulants?

Answer 35

1. Hydroxycoumarins | 2. Indanediones

Question 36

What is the main hydroxycoumarin type of anticoagulant?

Answer 36

Warfarin

Question 37

Main goal of Warfarin?

Answer 37

PREVENT blood clots from forming | - lengthens time it takes for a clot to form

Question 38

How does Warfarin try and prevent blood clots from forming?

Answer 38

By DECREASING the activity of Vitamin K 2,3-epoxide reductase enzyme

Question 39

What enzyme does Warfarin try to inhibit?

Answer 39

Vitamin K 2,3-epoxide reductase

Question 40

Hemophilia A

Answer 40

Factor VIII deficiency

Question 41

Where in secondary hemostasis, would a Factor VIII deficiency (Hemophilia A) be located?

Answer 41

It is needed at the end of the intrinsic pathway (along with Factor IX) to activate the common pathway and finish clot production

Question 42

How does one get Hemophilia A?

Answer 42

Usually hereditary but can be caused by spontaneous mutations

Question 43

With Hemophilia A, what type of bleed would you have the most trouble clotting?

Answer 43

Intrinsic - Trauma inside the vascular system