Unit 2 - Clotting Cascade

What is coagulation?

Converting fibrinogen (I) to fibrinogen (Ia) in order to build a framework for a platelet plug to block a broken vessel

What are procoagulants (clotting factors)?

Proteins found in blood plasma, produced by liver, which take part in the coagulation cascade/pathway

What is the extrinsic pathway of the clotting cascade?

Damaged tissues release factors → cascade begins with III and VII

What is the intrinsic pathway of the clotting cascade?

Factors in blood (XII from platelet degranulation) or a charged surface → cascade begins with XI, IX, VIII

What is factor I? Factor Ia? What pathway?

Fibrinogen (→ fibrin)

Common

[Fibrin is first!]

What is factor II? Factor IIa? What pathway?

Prothrombin (→ thrombin)

Common

What is factor III? What pathway?

Tissue factor (tissue thromboplastin)

Extrinsic

What is factor IV? What pathway?

Calcium ions

All pathways

What is factor V? Factor Va? What pathway?

Proaccelerin (→ accelerin)

Common

[V is for Very fast]

What is factor VII? Factor VIIa? What pathway?

Proconvertin (→ convertin)

Extrinsic

[Seven is a pro at convertin’ three!]

What is factor VIII? What pathway?

Antihemolytic factor A

Intrinsic

Deficiency → hemophilia A

[The Hapsburgs ate in every portrait]

What is factor IX? What pathway?

Antihemolytic factor B

Intrinsic

Deficiency → hemophilia B (Christmas disease)

What is factor X? What pathway?

Stuart-Prower factor (thrombokinase)

Common

[Think about how prowerful Malcolm X was!]

What is factor XI? What pathway?

Antihemolytic factor C

Intrinsic

Deficiency → hemophilia C (autosomal)

[Sail the eleven C’s]

What is factor XII? What pathway?

Hageman factor

Intrinsic, activates plasmin

[Hage a dozen donuts]

What is factor XIII? What pathway?

Fibrin-stabilizing factor

Stabilizes/cross-links fibrin (Ia)

What is von Willebrand disease?

A condition causing factor VIII to be ineffective (even though it is still present)

What is platelet-derived growth factor?

From platelets and endothelia, stimulates mitosis of fibroblasts/smooth muscle to repair a damaged vessel

What is fibrinolysis?

Clot dissolution

Factor XII speeds up formation of kallikrein (enzyme, converts plasminogen → plasmin)

What are the natural anticoagulants present in blood?

Heparin: from basophils and mast cells, interferes in formation of prothrombin activator (Xa + Va)

Antithrombin: from liver, deactivates thrombin (IIa) before it can act on fibrinogen (I)

What is the order of the extrinsic coagulation cascade (pathway)?

VII → VIIa

VIIa + III → activate X (X → Xa)

What is the order of the intrinsic coagulation cascade (pathway)?

XII → XIIa

XI → XIa

IX → IXa → activate X (X → Xa)

What is the order of the common coagulation cascade (pathway)?

X → Xa

Xa + Va → activate II (II → IIa)

I → Ia

Ia + XIII → cross-linked fibrin clot