I-hemostasis yomzimba womuntu yakhiwa ikakhulukazi izingxenye ezintathu:

1. Ukucindezeleka komthambo wegazi ngokwawo 2. Ama-platelet akha i-embolus 3. Ukuqaliswa kwezinto ezibangela ukujiya kwegazi

Uma silimala, silimaza imithambo yegazi engaphansi kwesikhumba, okungabangela ukuthi igazi lingene ezicutshini zethu, kwakha ukuphuka uma isikhumba siphelele, noma ukopha uma isikhumba siphukile. Ngalesi sikhathi, umzimba uzoqala inqubo yokwelapha nge-hemostatic.

Okokuqala, imithambo yegazi iyancipha, kunciphisa ukugeleza kwegazi

Okwesibili, ama-platelet aqala ukuhlangana. Uma umthambo wegazi wonakele, i-collagen iyavezwa. I-Collagen idonsela ama-platelet endaweni elimele, futhi ama-platelet ayanamathelana ukuze akhe i-plug. Akha ngokushesha isithiyo esisivimbela ekuphumeni kwegazi kakhulu.

I-Fibrin iyaqhubeka nokunamathela, okuvumela ama-platelet ukuthi axhumane ngokuqinile. Ekugcineni kwakheka ihlule legazi, elivimbela igazi eliningi ukuthi lingaphumi emzimbeni futhi livimbele namagciwane amabi ukuthi angangeni emzimbeni wethu evela ngaphandle. Ngesikhathi esifanayo, indlela yokujiya emzimbeni nayo iyavuselelwa.

Kunezinhlobo ezimbili zeziteshi zangaphandle nezangaphakathi.

Indlela yokujiya kwangaphandle: Iqalwa ngokuchayeka kwezicubu ezonakele ekuthinteni igazi ne-factor III. Lapho umonakalo wezicubu kanye nokuqhekeka kwemithambo yegazi, i-factor III eveziwe yakha inhlanganisela ene-Ca2+ kanye ne-VII ku-plasma ukuze isebenze i-factor X. Ngenxa yokuthi i-factor III eqala le nqubo ivela ezicutshini ezingaphandle kwemithambo yegazi, ibizwa ngokuthi i-extrinsic coagulation pathway.

Indlela yokujiya kwangaphakathi: eqalwa ukusebenza kwe-factor XII. Lapho umthambo wegazi wonakele futhi imicu ye-collagen engaphansi kwe-intimal iveziwe, ingenza kusebenze i-Ⅻ ibe yi-Ⅻa, bese ivula i-Ⅺ ibe yi-Ⅺa. I-Ⅺa ivula i-Ⅸa lapho kukhona i-Ca2+, bese i-Ⅸa yakha inhlanganisela ene-Ⅷa esebenzayo, i-PF3, kanye ne-Ca2+ ukuze isebenze i-X. Izici ezihilelekile ekujiya kwegazi enkambisweni eshiwo ngenhla zonke zikhona ku-plasma yegazi emithanjeni yegazi, ngakho-ke zibizwa ngokuthi indlela yokujiya kwegazi engaphakathi.

Lesi sici sinendima ebalulekile ekuhlanganiseni kwe-coagulation ngenxa yokuhlanganiswa kwezindlela ezimbili ezingeni le-factor X Factor X kanye ne-factor V kusebenze i-inactive factor II (prothrombin) ku-plasma kuya ku-active factor IIa, (thrombin). Lawa manani amakhulu e-thrombin aholela ekusebenzeni okwengeziwe kwama-platelet kanye nokwakheka kwemicu. Ngaphansi kwesenzo se-thrombin, i-fibrinogen encibilikisiwe ku-plasma iguqulwa ibe yi-fibrin monomers; ngesikhathi esifanayo, i-thrombin isebenza ku-XIII kuya ku-XIIIa, okwenza ama-fibrin monomers. Imizimba ye-fibrin ixhumana ukuze yakhe ama-polymer e-fibrin angancibiliki emanzini, futhi ihlangane ibe yinethiwekhi ukuze ivale amangqamuzana egazi, yakhe ama-blood clots, futhi iqedele inqubo yokujiya kwegazi. Le thrombus ekugcineni yakha uqweqwe oluvikela inxeba njengoba likhuphuka futhi lakha ungqimba olusha lwesikhumba ngaphansi kwama-Platelet kanye ne-fibrin ivuselelwa kuphela lapho umthambo wegazi uqhuma futhi uvezwa, okusho ukuthi emithanjeni yegazi evamile enempilo ayiholeli ngokungahleliwe kuma-clots.

Kodwa futhi kubonisa ukuthi uma imithambo yakho yegazi iqhuma ngenxa yokuminyana kwe-plaque, kuzobangela ukuba inani elikhulu lama-platelet liqoqeke, bese ekugcineni kwakha inani elikhulu lama-thrombus ukuvimba imithambo yegazi. Lokhu futhi kuyindlela yokwelapha isifo senhliziyo, i-myocardial infarction, kanye nesifo sohlangothi.