Reviewer: Jeremy Parsons, M.D. (see Reviewers page)
Revised: 9 June 2012, last major update June 2012
Copyright: (c) 2002-2012, PathologyOutlines.com, Inc.
● Primary hemostasis: initial step of forming platelet plug to stop bleeding from damaged vessel
● Secondary hemostasis: platelet plug is reinforced by fibrin clot; then fibrin clot is stabilized by activated factor XIII, which cross-links fibrin strands
● Tertiary hemostasis: as fibrin clot is formed, plasmin is generated to break down the clot
● Fibrin clot may occur via intrinsic or extrinsic pathway or both; in vivo it occurs via a hybrid model
● Coagulation factors in intrinsic or extrinsic pathway assemble on surface of activated platelets, which are usually at site of vascular injury
Many coagulation reactions also require calcium as a cofactor:
Note: “a” after factor number indicates “activated”
● Factor I: fibrinogen
● Factor II: prothrombin
● Factor III: tissue thromboplastin (tissue factor and phospholipid)
● Factor IV: ionized calcium
● Factor V: occasionally called labile factor or proaccelerin
● Factor VI: unassigned originally called accelerin later discovered to be activated Factor V
● Factor VII: occasionally called stable factor or proconvertin
● Factor VIII: antihemophilic factor
● Factor IX: plasma thromboplastin component, Christmas factor
● Factor X: occasionally called Stuart-Prower factor
● Factor XI: occasionally called plasma thromboplastin antecedent
● Factor XII: Hageman factor
● Factor XIII: fibrin-stabilizing factor
● High Molecular Weight Kininogen: occasionally called Fitzgerald factor
● Prekallikrein: occasionally called Fletcher factor
Intrinsic, common, and extrinsic pathways; chart credit to Kendall Crookston, M.D., PhD
The in vivo coagulation cascade; chart credit to Kendall Crookston, M.D., PhD
● Chandler WI (2005). Physiology of hemostasis. In B Spiess, R Spence, A Shander (Eds), Perioperative Transfusion Medicine (pp 77-92). Lippincott, Williams, & Wilkins.
End of Coagulation > General > Normal hemostasis
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