I-hemostasis yomzimba womuntu yakhiwa ikakhulukazi izingxenye ezintathu:

1. Ukuqina komkhumbi wegazi ngokwawo 2. Ama-platelet akha i-embolus 3. Ukuqaliswa kwezici zokuhlangana

Lapho silimala, silimaza imithambo yegazi engaphansi kwesikhumba, okungase kubangele igazi ukuthi lingene ezicutshini zethu, kwakheka imihuzuko uma isikhumba siphelele, noma ukopha uma isikhumba siphukile.Ngalesi sikhathi, umzimba uzoqala umshini we-hemostatic.

Okokuqala, imithambo yegazi iyacinana, inciphisa ukugeleza kwegazi

Okwesibili, ama-platelet aqala ukuhlangana.Lapho isitsha segazi sonakalisiwe, i-collagen iyavezwa.I-Collagen idonsela ama-platelet endaweni elimele, futhi ama-platelet anamathelana ukuze akhe ipulaki.Ngokushesha bakha umgoqo osivimbela ukuba singophi kakhulu.

I-Fibrin iyaqhubeka nokunamathisela, ivumela ama-platelet ukuthi axhumeke ngokuqinile.Ekugcineni ihlule legazi liyabumba, livimbele igazi eliningi ukuthi lingaphumi emzimbeni futhi livimbele amagciwane amabi ukuba angene emzimbeni wethu ngaphandle.Ngesikhathi esifanayo, indlela yokuhlangana emzimbeni nayo iyasebenza.

Kunezinhlobo ezimbili zamashaneli angaphandle nangaphakathi.

Indlela ye-Extrinsic coagulation: Iqalwa ngokuchayeka kwezicubu ezilimele ekuthinteni kwegazi nge-factor III.Lapho ukulimala kwezicubu nokugqabuka kwemithambo yegazi, isici III esiveziwe sakha inkimbinkimbi ene-Ca2+ ne-VII ku-plasma ukuze kusebenze i-factor X. Ngenxa yokuthi i-factor III eqala le nqubo ivela ezicutshini ezingaphandle kwemithambo yegazi, ibizwa ngokuthi i-extrinsic coagulation pathway.

Indlela ye-Intrinsic coagulation: iqalwe ngokusebenza kwe-factor XII.Uma umkhumbi wegazi wonakele futhi imicu ye-collagen engaphansi evezwa, ingenza kusebenze okuthi Ⅻ kuye ku-Ⅻa, bese kusebenzisa okuthi Ⅺ kuye ku-Ⅺa.Ⅺa yenza i-Ⅸa isebenze lapho kukhona i-Ca2+, bese okuthi Ⅸa yakhe inkimbi ene-Ⅷa, PF3, ne-Ca2+ ecushiwe ukuze iqhubeke isebenze i-X. Izici ezihilelekile ekuhlanganeni kwegazi kule nqubo eshiwo ngenhla zikhona ku-plasma yegazi emithanjeni yegazi. , ngakho-ke ziqanjwe njengendlela yokugaya igazi engaphakathi.

Lesi sici sinendima ebalulekile ku-coagulation cascade ngenxa yokuhlanganiswa kwezindlela ezimbili ezingeni le-factor X Factor X kanye ne-factor V ivule i-factor II engasebenzi (prothrombin) ku-plasma ibe yi-factor IIa esebenzayo, (thrombin) .Lawa manani amakhulu e-thrombin aholela ekusebenzeni okuqhubekayo kwamaplatelet kanye nokwakheka kwemicu.Ngaphansi kwesenzo se-thrombin, i-fibrinogen echithwa ku-plasma iguqulwa ibe yi-fibrin monomers;ngesikhathi esifanayo, i-thrombin ivuselela i-XIII kuya ku-XIIIa, yenza ama-fibrin monomers Imizimba ye-fibrin ixhumane ukuze yenze ama-fibrin polymers angancibiliki emanzini, futhi ixhumane ibe inethiwekhi ukuze ivale amangqamuzana egazi, yakhe amahlule egazi, futhi iqedele ukujiya kwegazi. inqubo.Le thrombus ekugcineni yakha utwayi oluvikela isilonda njengoba lukhuphuka futhi lwakha ungqimba olusha lwesikhumba ngaphansi kwama-Platelets kanye ne-fibrin acushwa kuphela lapho imithambo yegazi igqabuka futhi isobala, okusho ukuthi emithanjeni yegazi enempilo evamile ayiholeli ngokungahleliwe. amahlule.

Kodwa futhi kubonisa ukuthi uma imithambo yakho yegazi iphuka ngenxa yokufakwa kwama-plaque, kuzokwenza ukuthi inani elikhulu lamaplatelet lihlangane, futhi ekugcineni lenze inani elikhulu le-thrombus ukuvimba imithambo yegazi.Lokhu futhi kuyindlela ye-pathophysiological yesifo senhliziyo, i-myocardial infarction, kanye nesifo sohlangothi.