Hemostasis (or Haemostasis) refers to a process whereby bleeding is halted in most animals with a closed circulatory system.


The first medical description of the clinical and genetic features of hemostasis (concerning hemophilia) was by the so called "father of surgery" Abu al-Qasim al-Zahrawi, called thus for his extended original descriptions of operative techniques and instrumentation. He described, and, a method for stopping bleeding by local pressure and cauterisation. [Naday S. Hakim; Ruben Canelo, "Haemostasis in Surgery" (2007)]

Hemostasis in physiology

Hemostasis can refer to the physiologic process whereby bleeding is halted, thus protecting the integrity of the vascular system after tissue injury. It is responsible for minimizing blood loss. It is commonly referred to as stoppage of bleeding, however, coagulation is only one type of hemostatic process.

The hemostatic mechanisms have several important function:
# Maintain blood in a fluid state while circulating within the vascular system
# Arrests bleeding at the site of injury by formation of hemostatic plug
# Ensure the removal of the hemostatic plug when healing is complete

The components of normal hemostasis include: Blood vessels, platelets, plasma coagulation factors and their inhibitors and the fibrinolytic system.

When a blood vessel is wounded, several steps occur to staunch the flow of blood, namely:

* Vasoconstriction constricts the blood vessel, minimizing vessel diameter and slowing bleeding.
* Primary hemostasis occurs, wherein platelets, one of the formed elements of the blood, bind to collagen in the exposed walls of the blood vessel to form a hemostatic plug within seconds after an injury.
* Secondary hemostasis or coagulation occurs. This involves a complex cascade of coagulation factors, ultimately resulting in the transformation of fibrinogen, a blood protein, into polymerized fibrin making a clot. This process takes several minutes.
* The clot attracts and stimulates the growth of fibroblasts and smooth muscle cells within the vessel wall, and begins the repair process which ultimately results in the dissolution of the clot (fibrinolysis).

Disorders of Hemostasis

Disorders of hemostasis can be roughly divided into:
* Platelet disorders, such as idiopathic thrombocytopenic purpura, and
* Disorders of coagulation, such as hemophilia and thrombophilia.

Hemostasis may also refer to the complex interaction between vessels, platelets, coagulation factors, coagulation inhibitors and fibrinolytic proteins to maintain the blood within the vascular compartment in a fluid state. The objective of the hemostatic system is to preserve intravascular integrity by achieving a balance between hemorrhage and thrombosis.

Hemostasis can be induced by adenosine diphosphate (ADP) at the site of a mosquito bite to recruit platelets and oppose bloodfeeding; however mosquitoes have developed salivary apyrase to degrade ADP to counter this defense.

Hemostasis by hemostatic clamps

Hemostasis may refer to the process of manually clamping a blood vessel, usually with hemostatic clamps, in surgery or dissection, to prevent bleeding from that vessel. This also may be done when an abnormal blood vessel forms, as these vessels may have thin walls and be prone to rupturing.

External Links

[http://www.mhhe.com/biosci/esp/2002_general/Esp/folder_structure/tr/m1/s7/trm1s7_3.htm Hemostasis slides from McGraw-Hill]




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Look at other dictionaries:

  • hemostasis — o hemóstasis (plural hemostasis) sustantivo femenino 1. Área: medicina Detención de una hemorragia por medios naturales o terapéuticos …   Diccionario Salamanca de la Lengua Española

  • hemostasis — (De hemo y el gr. στάσις, detención). f. Med. hemostasia …   Diccionario de la lengua española

  • hemostasis — [hē΄mō stā′sis, hem΄ōstā′sis] n. pl. hemostases [ModL < Gr haimostasis: see HEMO & STASIS] 1. the natural or surgical stoppage of bleeding 2. slowing or stoppage of the flow of blood in a vein or artery, as with a tourniquet, blood clot, etc …   English World dictionary

  • hemostasis — (Del gr. haima, sangre + histemi, detener.) ► sustantivo femenino MEDICINA Detención, esporádica o artificial, de una hemorragia: ■ le produjeron la hemostasis con fármacos. IRREG. plural hemostasis * * * hemostasis (de «hemo » y el gr. «stásis» …   Enciclopedia Universal

  • hemostasis — {{#}}{{LM H40983}}{{〓}} {{[}}hemostasis{{]}} ‹he·mos·ta·sis› {{◆}}(pl. hemostasis){{◇}} {{《}}▍ s.f.{{》}} → {{↑}}hemostasia{{↓}}. {{★}}{{\}}ETIMOLOGÍA:{{/}} De hemo (sangre) y el griego stásis (detención) …   Diccionario de uso del español actual con sinónimos y antónimos

  • Hemostasis — The stoppage of bleeding or hemorrhage. Also, the stoppage of blood flow through a blood vessel or organ of the body. Hemostasis is the arrest of bleeding, whether it be by normal vasoconstriction (the vessel walls closing temporarily), by an… …   Medical dictionary

  • hemostasis — noun Etymology: New Latin, from Greek haimostasis styptic, from haimo hem + stasis Date: 1843 arrest of bleeding …   New Collegiate Dictionary

  • hemostasis — /hi mos teuh sis, hee meuh stay sis, hem euh /, n. Med. 1. the stoppage of bleeding. 2. the stoppage of the circulation of blood in a part of the body. 3. stagnation of blood in a part. Also, hemostasia /hee meuh stay zheuh, zhee euh, zee euh,… …   Universalium

  • hemostasis — noun /ˌhiːmɵˈsteɪsəs/ The process of keeping blood inside a damaged vessel to stop bleeding. See Also: hemostatic, hemodynamics …   Wiktionary

  • hemostasis — Conjunto de los procesos fisiológicos que concurren en la coagulación de la sangre. Ver también: coagulación; fibrinolisis …   Diccionario ecologico

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