Topic 12 - Haemostasis: coagulation cascade mechanism

Question 1

Words to include

Answer 1

• Defense reaction
• Internal and external vessel injury

Central cascade

• Internal or external vessel injury
• Factors of the extrinsic and intrinsic way
  
  • X (Stuart-Prower)
    
    • Xa
  • Activation complex:
    
    • Xa
    • IV (Ca)
    • Va
    • PFD3 (Thrombocyte phospholipid)
  • II (Prothrombin)
    
    • IIa (Thrombin)
  • I (Fibrinogen)
    
    • Ia (Loose fibrin)
  • Ib (Stable fibrin)
  • XIII-XIIIa (Lóránd-Laki factor)

Extrinsic way of coagulation

• External tissue injuries
• VII (Proconvertin)
  
  • VIIa (Convertin)
• III (Thromboplastin/thromokinase)
  
  • Tissue factor
• X (Sturart-Prower
  
  • Xa

Intrinsic way of coagulation

• Negatively charge collagen surface, intama injury
• XII (Hageman, contact factor) in presence of kininogen & kallikrein
  
  • XIIa
• XI (Plasma thromboplastin antecedent (PTA))
  
  • XIa
• IX (Christmas factor)
  
  • IXa
• Activation complex
  
  • IXa
  • IV (Calcium)
  • TF3 (Thrombocyte phospholipid)
• X (Stuart-Prower)
  
  • Xa
• Haemophilia A
  
  • Factor VIII (ø)
• Haemophilia B
  
  • Factor IX (ø)

Question 2

Topics to include in the essay

Answer 2

1. Haemopstasis (role)
2. Central cascade
   
   • Role of thrombin
   • Extrinsic way of coagulation
   • Intrinsic way of coagulation
3. Haemophilia A and B

Question 3

What is haemostasis?

Answer 3

Haemostasis is a complex defense reaction which prevents the loss of blood in case on internal or external vessel injury

Question 4

Central cascade: figure

Answer 4

Question 5

Roles of thrombin: figure

Answer 5

Question 6

Extrinsic way of coagulation: figure

Answer 6

• Activates in case of external tissue injury

Question 7

Intrinsic way of coagulation: figure

Answer 7

Question 8

Haemophilia: reason and types

Answer 8

• Haemophilia A: lack of factor VIII
• Haemophilia B: lack of factor IX