Imithambo yegazi (umkhumbi: usuka ku-Latin vascellum ephansi, kusukela ku-classical Latin vasculum, okusho isitsha esincane, igazi: kusuka ku-Latin sanguineus) izitho zokujikeleza kwegazi.

Incazelo jikelele. Imithambo yegazi yenza umjikelezo ovaliwe lapho igazi lijikeleza khona. Lo mjikelezo uhlukaniswe umjikelezo omkhulu womzimba kanye nokujikeleza okuncane kwamaphaphu. Lezi zitsha zihlanganisa udonga olunezingubo ezintathu: (1) (2)

• Ijazi elingaphakathi, noma i-intima, elakhiwe ungqimba lwamaselula we-endothelium kanye nolwelwesi lwangaphakathi lwemikhumbi;
• Ingubo emaphakathi, noma imidiya, eyakha ungqimba oluphakathi futhi yakhiwe imicu yemisipha nenwebeka;
• Isendlalelo sangaphandle, noma i-adventitia, esakha ungqimba olungaphandle futhi lwakhiwe imicu ye-collagen nezicubu ezine-fibrous.

Imithambo yegazi ihlukaniswe ngamaqembu ahlukene (1)

• Imithambo yegazi. Imithambo yakha imithambo lapho igazi, elinomoya-mpilo ocebile, lishiya inhliziyo ukuze lifinyelele ezakhiweni ezihlukahlukene zomzimba, ngaphandle kokujikeleza kwamaphaphu kanye ne-placenta. Kunezinhlobo ezahlukene zemithambo kuye ngokuthi kwakheka kanjani1.

  - Imithambo yohlobo lokunwebeka, enezinga elikhulu, inodonga oluwugqinsi futhi yakhiwe imicu eminingi enwebekayo. Atholakala ikakhulukazi eduze kwenhliziyo, njenge-aorta, noma umthambo wamaphaphu.

  - Imithambo yohlobo lwemisipha inezinga elincane futhi udonga lwayo luqukethe imicu eminingi yemisipha ebushelelezi.

  - I-arterioles itholakala ekupheleni kwenethiwekhi ye-arterial, phakathi kwemithambo kanye nama-capillaries. Ngokuvamile zenziwe zasendaweni esithweni futhi aziqukethe ijazi langaphandle.

• Imithambo. Imithambo yimithambo lapho igazi, elingenawo umoya-mpilo, lishiya i-periphery ukuze lifinyelele inhliziyo, ngaphandle kokujikeleza kwamaphaphu ne-placenta. Kusuka kuma-capillaries, ama-venules, imithambo emincane, ibuyisa igazi elingenawo umoya-mpilo bese ijoyina imithambo. (1) Laba bakamuva banodonga oluncanyana kunemithambo. Udonga lwazo lunemicu encane yokunwebeka kanye nemisipha kodwa lunengubo yangaphandle ewugqinsi. Imithambo inomsebenzi wokukwazi ukuqukatha igazi eliningi kunemithambo. Ukuze kube lula ukubuya kwe-venous, imithambo yemilenze engezansi inama-valve. (2)
• Imithambo. Imithambo yimithambo lapho igazi, elingenawo umoya-mpilo, lishiya i-periphery ukuze lifinyelele inhliziyo, ngaphandle kokujikeleza kwamaphaphu ne-placenta. Kusuka kuma-capillaries, ama-venules, imithambo emincane, ibuyisa igazi elingenawo umoya-mpilo bese ijoyina imithambo. (1) Laba bakamuva banodonga oluncanyana kunemithambo. Udonga lwazo lunemicu encane yokunwebeka kanye nemisipha kodwa lunengubo yangaphandle ewugqinsi. Imithambo inomsebenzi wokukwazi ukuqukatha igazi eliningi kunemithambo. Ukuze kube lula ukubuya kwe-venous, imithambo yemilenze engezansi inama-valve. (2)
• Ama-Capillaries. Ukwakha inethiwekhi yamagatsha, ama-capillaries ayizitsha ezinhle kakhulu, ezinobubanzi obusuka ku-5 kuya ku-15 micrometer. Benza uguquko phakathi kwama-arterioles nama-venule. Bavumela kokubili ukusatshalaliswa kwegazi oksijini kanye nezakhi; kanye nokubuyiswa kwe-carbon dioxide kanye nemfucuza ye-metabolic. (1)

Ukuswela. Imithambo yegazi ivalwe imicu yezinzwa enozwela ukuze ilawule ububanzi bayo. (1)

Ukusabalalisa/Ukuqedwa. Imithambo yegazi ivumela kokubili ukusatshalaliswa kwezakhi kanye nokubuyiswa kwemfucuza ye-metabolic.

Ukujikeleza kwegazi. Imithambo yegazi yenza umjikelezo ovaliwe. Igazi eligcwele izakhamzimba lishiya i-ventricle yesokunxele yenhliziyo nge-aorta. Ngokulandelanayo inqamula imithambo, ama-arterioles, ama-capillaries, ama-venule nemithambo. Kuma-capillaries, ukushintshaniswa kwezakhi kanye nemfucuza kwenzeka. Igazi elingenazo izakhamzimba libe selifinyelela ku-atrium elungile yenhliziyo ngokusebenzisa i-vena cavae emibili ngaphambi kokuzicebisa ngemisoco futhi liqale kabusha uhambo lwalo emzimbeni. (1) (2)

Izinkinga ezihlobene nomfutho wegazi. Umfutho wegazi omningi ngokumelene nezindonga zemithambo yegazi kungaholela ekucindezelekeni kwegazi eliphezulu futhi kungase kwandise ingozi yesifo semithambo yegazi.3 Ngokuphambene, umfutho ophansi kakhulu ubangela umfutho wegazi ophansi.

I-Thrombosis. Le pathology ihambisana nokwakheka kwehlule legazi emithanjeni yegazi (4).

Stroke. Ingozi ye-Cerebrovascular, noma i-stroke, ibonakala ngokuvinjelwa komkhumbi wegazi ebuchosheni, njengokwakheka kwamahlule egazi noma ukuphuka komkhumbi. (4)

Isikhukhula. Ebizwa nangokuthi i-venous thrombosis, le pathology ihambisana nokwakheka kwehlule legazi, noma i-thrombus, emithanjeni. Lawa mahlule anganyakaza futhi akhuphukele e-inferior vena cava. Le pathology ingaholela ezimeni ezahlukahlukene njengokungasebenzi kahle kwe-venous, okusho ukungasebenzi kahle kwenethiwekhi ye-venous (5).

Izifo zenhliziyo. Zihlanganisa izifo eziningi ezifana ne-myocardial infarction noma i-angina pectoris. Lapho lezi zifo zenzeka, imithambo yegazi ivame ukuthinteka futhi ingabangela ikakhulukazi ukuntuleka komoya-mpilo. (6) (7)

Izidakamizwa zokwelapha. Ngokuya nge-pathology etholakele, izidakamizwa ezithile zingase zibekwe njengama-anticoagulants, anti-aggregants, noma ama-anti-ischemic agents.

I-Thrombolyse. Isetshenziswa ngesikhathi semivimbo, le ndlela yokwelashwa iqukethe ukuqaqa i-thrombi, noma amahlule egazi, ngosizo lwezidakamizwa. (5)

Ukwelapha okuhlinzwa. Ngokuya nge-pathology etholakele kanye nokuziphendukela kwayo, ukuhlinzwa kungadingeka.

Ukuhlolwa komzimba. Okokuqala, kwenziwa ukuhlolwa komtholampilo ukuze kuhlonzwe futhi kuhlolwe ubuhlungu obubonwa yisiguli.

Izivivinyo ze-Medical imaging. I-X-ray, i-CT, i-MRI, i-coronary angiography, i-CT angiography, noma ukuhlolwa kwe-arteriography kungasetshenziswa ukuqinisekisa noma ukujulisa ukuxilongwa.

• I-Doppler ultrasound. Le-ultrasound ethize yenza sikwazi ukubona ukuhamba kwegazi.

UWilliam Harvey, udokotela oyiNgisi wekhulu le-16 nele-17, waziwa ngomsebenzi wakhe nezinto azitholile mayelana nokusebenza kokujikeleza kwegazi.