Coagulation
Physiology
Hemostasis
Author: Jeremy C. Parsons, M.D.
Topic Completed: 1 June 2012
Minor changes: 22 September 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Hemostasis [title]
Cite this page: Parsons JC. Hemostasis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/coagulationnormalhemostasis.html. Accessed October 20th, 2021.
Definition / general
- Involves formation of blood clots to stop bleeding from damaged vessels, and activation of natural anticoagulation and fibrinolytic systems to limit clot formation to sites of injury
- Bleeding disorders are due to defects in clot formation or overactive fibrinolytic systems
- Hypercoagulability disorders are due to defects in anticoagulant system or underactive fibrinolytic systems
- 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
Diagrams / tables
Images hosted on other servers:
Coagulation
Intrinsic, common, and extrinsic pathways
In vivo coagulation cascade
Additional references
