Clotting Cascade Flashcards Preview

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Flashcards in Clotting Cascade Deck (43)
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1
Q

Hemostasis

A

Clotting to stop blood flow

2
Q

What occurs with primary hemostasis?

A

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

3
Q

What is formed with primary hemostasis?

A

Platelet plug at injury site

4
Q

What occurs with secondary hemostasis?

A

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

5
Q

What is formed with secondary hemostasis?

A

Fibrin mesh over the platelet plug to reinforce it

6
Q

What are the 2 pathway options for secondary hemostasis?

A

Extrinsic pathway

Intrinsic pathway

7
Q

What activates the extrinsic pathway for secondary hemostasis?

A

External trauma - blood escapes vascular system

8
Q

Which pathway for secondary hemostasis is quickest?

A

Extrinsic

9
Q

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

A

Factor VII

10
Q

Describe the extrinsic pathway

A

Factor VII + Tissue factor = VIIa (activated form)

- Then goes to common pathway

11
Q

What activates the intrinsic pathway for secondary hemostasis?

A

Trauma inside the vascular system;

platelets, chemicals, collagen

12
Q

Which pathway for secondary hemostasis is slowest?

A

Intrinsic

13
Q

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

A

Factors XII, XI, IX, VIII

14
Q

Describe the intrinsic pathway

A

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

15
Q

What is the common pathway?

A

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

16
Q

What factors activate the common pathway for secondary hemostasis?

A

Factors VII, VIII, IX

17
Q

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

A

X and V

18
Q

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

A

II (thrombin)

19
Q

Factor II

A

Thrombin

20
Q

What does Factor II (thrombin) activate?

A
  1. Takes Fibrinogen –> Fibrin

2. Activates Factor XIII

21
Q

What takes Fibrin –> Cross-linked fibrin mesh?

A

Factor XIII

22
Q

What are the major actions of thrombin?

A
  • Creates Fibrin
  • Activation of Factor XIII
  • Activation of platelets
  • Creates more thrombin
23
Q

Describe the common pathway for secondary hemostasis?

A

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!
24
Q

Is primary or secondary hemostasis quicker?

A

Primary

25
Q

Where is Vitamin K activated?

A

Liver

26
Q

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

A

Vitamin K 2,3-epoxide reductase

27
Q

What is the first step in Vitamin K activation?

A

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

28
Q

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

A

Vitamin K quinone reductase

29
Q

What is the second step in Vitamin K activation?

A

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

30
Q

What is the active form of Vitamin K?

A

Vitamin K Quinol

31
Q

What factors and proteins are activated by Vitamin K Quinol?

A

Factors II, VII, IX, X

Proteins S and C

32
Q

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

A

Vitamin K 2,3-epoxide

33
Q

What factors and proteins are activated by Vitamin K Quinol?

A

Factors II, VII, IX, X

Proteins S and C

34
Q

What is the mechanism of action of anticoagulants?

A

Vitamin K INHIBITION

35
Q

What are the 2 types of anticoagulants?

A
  1. Hydroxycoumarins

2. Indanediones

36
Q

What is the main hydroxycoumarin type of anticoagulant?

A

Warfarin

37
Q

Main goal of Warfarin?

A

PREVENT blood clots from forming

- lengthens time it takes for a clot to form

38
Q

How does Warfarin try and prevent blood clots from forming?

A

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

39
Q

What enzyme does Warfarin try to inhibit?

A

Vitamin K 2,3-epoxide reductase

40
Q

Hemophilia A

A

Factor VIII deficiency

41
Q

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

A

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

42
Q

How does one get Hemophilia A?

A

Usually hereditary but can be caused by spontaneous mutations

43
Q

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

A

Intrinsic - Trauma inside the vascular system