IVasoconstriction yindlela yokusebenza komzimba ebangela ukuthi ubukhulu bemithambo yegazi yomzimba yehle ngokuncipha kwemisipha eyakha ulwelwesi lwemithambo yegazi (imithambo, imithambo). Kungabangelwa izizathu nezici eziningana, kepha kunoma yikuphi ukuphendula ngokushesha ekuvumelaneni okudingekayo, ikakhulukazi ukumisa ukopha.

IVasoconstriction inqubo yemvelo equkethe ukunciphisa ububanzi bemithambo yegazi, ngokuncipha kwemicu yayo yemisipha. Isenzo saso esiphikisanayo sihambisana ne-vasodilation; kokubili ukunyakaza kuhlanganisa lokho okubizwa ngokuthi yi-vasomotricity.

IVasoconstriction inokusetshenziswa kokunciphisa, ngokwesibonelo, ukopha lapho kuvela isilonda somthambo wegazi. Lesi yisigaba sokuqala se-heestasis. Izikhungo zemizwa ze-vasoconstrictor zisekuqaleni kwalomshini, kepha futhi namahomoni angiotensin, adrenaline kanye noradrenaline. IVasoconstriction ngaleyo ndlela ibangela ukwehla kokugeleza kwegazi esithweni okukhulunywa ngaso. Ubuso besikebhe buzobe sebunamathela ndawonye, ​​buba ingcina.

Kunezici eziningana ezibangela i-vasoconstriction emzimbeni. Okuvame kakhulu ukulimala kwamaseli emisipha, imithambo yayo yegazi, ngokuvimba, izomisa ukopha.

Izinto ezithile nazo zibangela lokhu kuqiniswa:

• I-Serotonin, ekhishwe ngama-platelets;
• Ukwenza kusebenze ama-receptors wezinhlungu adlula ohlelweni lwezinzwa (ama-catecholamines, adrenaline, noradrenaline);
• Ubuthi obuthile noma imikhiqizo ekhona ekudleni (ngokwesibonelo, i-caffeine).

Ngaphandle kwalezi zimbangela zokuqala, inqubo ye-vasoconstriction ingasethwa ngesikhathi sokulawulwa kokushintshana kokushisa emzimbeni, okubandakanya izinhlelo zezinzwa, ze-endocrine, zenhliziyo nezokuphefumula.

Lapho izinga lokushisa lomzimba lehla, ngokwesibonelo lapho kubanda kakhulu, umuntu angabona ukuvela kwe-vasoconstriction enqamulelayo: le nto yenza kube nokwenzeka ukuhlukanisa izicubu zomngcele maphakathi nomzimba. Ukuncipha kobubanzi bemithambo yegazi emaphethelweni omzimba kunomphumela wokubuyisa “umyela” (umehluko) ekushiseni phakathi kwesikhumba nezitho zenhliziyo, amaphaphu, ubuchopho, izinso. Kuhambisana nomfutho wegazi ophakeme kanye nokwanda kwethoni yesistimu yezinzwa, ngaleyo ndlela i-vasoconstriction inyusa izinga lokushaya kwenhliziyo. Lokhu kuholela ekukhuleni okungu-10% ekugxileni kwe-plasma kwamaseli abomvu namhlophe egazi, ama-platelets, kepha ne-cholesterol ne-fibrinogen. Umphumela: ukwanda kwe-viscosity yegazi cishe ngama-20%.

Ekuphetheni, lapho umzimba wakho ubhekene namakhaza, i-thermostat yangaphakathi ivuleka ngokuzenzekelayo bese ishisa inani elikhulu lamandla. Izidingo zenhliziyo nezidingo zomoya-mpilo nazo ziyanda.

Ukucindezeleka, umthwalo? 

Futhi, ingcindezi nayo ingabophezela ekusebenzeni kwe-vasoconstriction. Ngokwenza kwe-adrenaline, ukuthumela umyalezo wokugcina ngesikhathi, imikhumbi izosebenza ukuqinisa ububanzi bayo, okwesikhashana.

nicotine

I-nicotine ibangela i-vasoconstriction emithanjeni yegazi, inciphisa ukuhamba kwegazi, ngakho-ke inani le-oksijini elinikezwa izicubu nobuthi obususwe ezicutshini ezifanayo.

Le vasoconstriction iyabuyiselwa emuva futhi inyamalale emahoreni ambalwa ngemuva kokubhema. IVasoconstriction iba unomphela emini, kubantu ababhemayo abaphezulu.

Izifo ezingaba khona

Ekugcineni, i-vasoconstriction ingaba uphawu lokugula okungenzeka, ukudakwa noma i-envenomation. Isibonelo, i-Raynaud's syndrome iboniswa yi-vasoconstriction eyeqile yemikhumbi emikhawulweni yomzimba (izandla, izinyawo), ikakhulukazi ngesikhathi sezulu esibandayo noma sokuxineka. Lesi sifo sidala ukulahleka kokutholakala kwegazi endaweni ethintekile nobuhlungu lapho ukugeleza kwegazi kubuyela kulezo zindawo ezifanayo.

IVasoconstriction ingabangelwa ukwelashwa kwezidakamizwa, ukuze kunciphise ukopha okuthile ezimweni ezithile.

Ukunyakaza kwemithambo yegazi kungumphumela ophambene we-vasoconstriction ngakho-ke kufana nokwanda kosayizi wemikhumbi ngokwehliswa.

Lokhu kunwebeka kwenzeka ngokuphumula kwemisipha ezungeze imithambo yegazi.

Izimbangela ze-vasodilation yilezi:

• Ukushisa ;
• Ukugula, ubuthi, i-envenomation;
• Ukungezwani komzimba, ukuvuvukala (i-edema);
• Utshwala bunomphumela we-vasodilator futhi buvule imithambo yegazi ebuchosheni;
• Kubangelwa isidakamizwa, njengezidakamizwa ezinegazi.

Kulokhu kokugcina, umuntu one-hypertension unemikhumbi "emincane kakhulu" ukuthi ingafakwa umfutho wegazi emithanjeni yabo, ayilimaze. Ngakho-ke sizosebenzisa umuthi ukukhulisa imithambo yawo ukuze sinciphise umfutho wegazi.