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*(Haima=darah, stasis=berhenti)Yaitu Proses penghentian perdarahan secara spontan dari pembuluh darah yang mengalami kerusakan.HEMOSTASIS

*HEMOSTASIS :is the process which retains the blood within the vascular system. Hemostatic process is designed to repair the break and arrest hemorrhage.

The most immediate response to bleeding are from:VascularBy Vasoconstriction mechanism, which decreases the blood flow through the injured blood vesselPlateletsPlatelets clump together and adhere to the injured vessel in this area in order to form a plug, and further inhibit bleedingThe Coagulation factorsBy forming a fibrin meshwork or clot to stop the bleeding completely

*Hemostasis diperankan oleh 3 faktor:FaktorVASKULERFaktorTROMBOSITFaktorPEMBEKUAN

Struktur Vaskuler*

Mekanisme Hemostasis*

Hemostasis or haemostasis is a process which causes bleeding to stop, meaning to keep blood within a damaged blood vessel.

Hemostatis adalah proses dimana ada 5 faktor yang berinteraksi, yaitu :Dinding pembuluh darah, Trombosit, Faktor koagulasi, Sistem fibrinolisis, dan Inhibitor. Tujuan Hemostasis :agar darah tetap cair di dalam pembuluh, mencegah kehilangan darah karena luka, memperbaiki aliran darah selama proses penyembuhan luka. menghentikan dan mengontrol perdarahan dari pembuluh darah yang terluka*

Vasoconstriction of a damaged blood vessel slows the flow of blood and thus helps to limit blood loss. This process is mediated by:Local controls. Vasoconstrictors such as thromboxane are released at the site of the injury. Systemic control. Epinephrine released by the adrenal glands stimulates general vasoconstriction.

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Formation of a Platelet Plug. When a blood vessel is damaged, the blood is exposed to collagen fibers in the basement membrane of the vessel (shown in green below). Platelets stick to collagen and become activated. Activated platelets release chemicals such as ADP, and thromboxane, that cause the aggregation of more platelets to the site of injury. Platelet aggregation results in the formation of a platelet plug which acts to stem the flow of blood from the broken vessel. It is essential that platelets become activated only at the site of a broken vessel. Otherwise activated platelets would form plugs and induce clots in inapropriate places. Healthy vessels secrete an enzyme called prostacyclin that functions to inhibit platelet activation and aggregation.*

Clotting of Blood The blood contains about a dozen clotting factors. These factors are proteins that exist in the blood in an inactive state, but can be called into action when tissues or blood vessels are damaged. The activation of clotting factors occurs in a sequential manner. The first factor in the sequence activates the second factor, which activates the third factor and so on. This series of reactions is called the clotting cascade. Blood clotting is the transformation of liquid blood into a semisolid gel. Clots are made from fibers (polymers) of a protein called fibrin. Fibrin monomers come from an inactive precursor called fibrinogen. The body of the fibrinogen molecule has caps on its ends that mask fibrin-to-fibrin binding sites. If the caps are removed then fibrin monomers polymerize to form fibrin polymers. This process requires thrombin, the enzyme that converts fibrinogen to fibrin. This process also requires calcium, which acts as a kind of glue to hold the fibrin monomers to each other to form the polymeric fiber. The fibrin fibers form a loose meshwork that is stabilized by clotting factor XIII. The stabilized meshwork of fibrin fibers traps erythrocytes, thus forming a clot that stops the flow of blood.*

*VASCULER

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*VASCULER

*FASE VASKULERARTERIOLKAPILLERVENULAARTERIMIKROSIRKULASIVENABEROTOT TEBALKENYALTRAUMA BERAT RUSAKHALUSMUDAH RUSAKTIPISTRAUMA RINGAN RUSAK

*FASE VASKULER

PERANAN FASE VASKULER :

REFLEKS : Aliran darah menurunA. VASOKONSTRISI : LOKAL :1. SEROTIN = 5 HT = 5 HIDROSITRIPTAMIN2. EPINEFRINE menurun3. TROMBOKSAN A2

*FASE VASKULER

B. DIIKUTI PROSES HEMOSTASIS LAIN : TROMBOSIT : PENONJOLAN KOLAGEN ADHESI AGREGASI

KOAGULASI : INTRINSIK : F XII F XII a EKSTRINSIK: dilepaskan F III = (Tromboplastin Jaringan)

*vascularHEMOSTATICPLUG= SUMBATAN PASE1: - SUMBATAN AGREGASI - REVERSIBELPASE 2: - AGGREGASI SEKUNDER - IRREVERSIBEL

UNTUK AGREGASI DIPERLUKAN:1. ION KALSIUM 2. FIBRINOGEN

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