Coagulation and kinin pathways

Question 1

Name two initiators of the intrinsic coagulation pathway

Answer 1

Factor XII is converted to XIIa in the presence of endothelial damage (collagen basement membrane and activated platelets) and by high-molecular-weight kininogen

Question 2

What part of the fibrinolytic system also activates the complement cascade by cleaving C3 to C3a?

Answer 2

Plasmin

Question 3

Kallikrein links the coagulation cascade to the kinin cascade through its activation of _____ and to the fibrinolytic system through its activation of _____

Answer 3

Bradykinin; plasminogen (to plasmin)

Question 4

Name two reactions initiated by high-molecular-weight kininogen

Answer 4

High-molecular-weight kininogen is the initial reagent in the kinin cascade and stimulates the coagulation cascade by interacting with factor XII

Question 5

What does plasmin create when it interacts with fibrin clots?

Answer 5

Fibrin split products (fibrin degradation)

Question 6

Once high-molecular-weight kininogen cleaves to form bradykinin, what are the effects of the kinin cascade?

Answer 6

Vasodilation, vascular permeability, and pain

Question 7

What factor converts prokallikrein to kallikrein and factor XI to XIa?

Answer 7

Factor XIIa; it is thus involved in both the kinin cascade and the coagulation cascade

Question 8

Which coagulation factors are specific to the intrinsic coagulation pathway?

Answer 8

Factor XII, factor XI, factor IX, and factor VIII

• Summary:*
• VIII to XII except X which is common pathway

Question 9

Which coagulation factors are specific to the extrinsic coagulation pathway?

Answer 9

Factor VII and tissue factor (thromboplastin)

• Memory aid:*
• Seven has letter E for Extrinsic

Question 10

Which coagulation factors are common to both the intrinsic and extrinsic coagulation pathways?

Answer 10

Factor X, factor V, factor II (prothrombin), and factor XIII

Question 11

What is the end result of the coagulation cascade?

Answer 11

The conversion of fibrinogen into fibrin to form a fibrin mesh that will stabilize the platelet plug

Question 12

Which reactions in the coagulation cascade require calcium and a phospholipid surface as cofactors?

Answer 12

• The conversion of factors
  
  • IX to IXa
  • VII to VIIa
  • X to Xa
  • II to IIa

Question 13

What are two stimuli for the conversion of factor X to factor Xa?

Answer 13

Activated factor VIIa, or factor IXa with factor VIIIa as a cofactor; this is where the intrinsic and extrinsic pathways converge

Question 14

Which four reactions is thrombin involved in?

Answer 14

Thrombin (IIa) cleaves fibrinogen into fibrin monomers, activates factor XIII to help stabilize and cross-link the fibrin mesh, and activates both factor VIII and factor V

Question 15

What ion does factor XIII require to stabilize the fibrin mesh?

Answer 15

Calcium

Question 16

Factors affected in each hemophilia type

Answer 16

• Hemophilia A
  
  • Factor VIII (XR)
• Hemophilia B
  
  • Factor IX (XR)
• Hemophilia C
  
  • Factor XI (AR)

Question 17

What reaction accounts for the effects of heparin?

Answer 17

Heparin activates antithrombin, resulting in inhibition of thrombin and factors IXa, Xa, XIa, and XIIa

Question 18

Name four mediators of thrombus formation or degradation that are found within the vascular endothelial cell

Answer 18

• von Willebrand’s factor
• Thromboplastin
• Tissue plasminogen activator
• Prostaglandin I2