Umehluko Phakathi Kwemithambo Nemithambo
Uhlelo lokujikeleza kwegazi lomuntu luyinethiwekhi eyinkimbinkimbi equkethe inhliziyo, imithambo yegazi, imithambo yegazi kanye nama-capillary asebenzisana ukuze asakaze igazi emzimbeni wonke. Imithambo yegazi kanye nemithambo yegazi yizinhlobo ezimbili eziyinhloko zemithambo yegazi ezidlala indima ebalulekile kulesi simiso. Nakuba zombili zisebenza ukuthutha igazi, zinezinhlobo eziningana ezibalulekile zesakhiwo kanye nokusebenza. Lesi sihloko sizoxoxa ngale mehluko ngokuningiliziwe kanye nemiphumela yayo empilweni yomuntu kanye nomsebenzi wakhe.
Isakhiwo kanye nendawo
Imithambo yegazi iyimithambo yegazi ethwala igazi isuka enhliziyweni iye emzimbeni wonke. Izindonga zemithambo yegazi zinezendlalelo ezintathu eziyinhloko: i-tunica intima (ungqimba lwangaphakathi), i-tunica media (ungqimba oluphakathi), kanye ne-tunica adventitia (ungqimba lwangaphandle). I-tunica media, eyakhiwa kakhulu yimisipha ebushelelezi kanye nezicubu ezinwebekayo, ijiyile kakhulu futhi ivumela imithambo yegazi ukuthi imelane nomfutho wegazi ophakeme ophuma enhliziyweni. Imithambo yegazi ivame ukutholakala ngaphakathi emzimbeni, ihlinzeka ngokuvikeleka okwengeziwe ekulimaleni.
Ngokuphambene nalokho, imithambo yegazi iyimithambo yegazi ethwala igazi ibuyele enhliziyweni. Isakhiwo sayo sifana nesemithambo yegazi, esakhiwe ngezingqimba ezintathu, kodwa i-tunica media emithanjeni incane kakhulu futhi iqukethe imisipha ebushelelezi kanye nemicu enwebekayo embalwa. Lokhu kuyenza ithambe futhi iguquguquke kalula. Imithambo eminingi iseduze nobuso besikhumba. Imithambo yegazi iphinde ifakwe ama-valve ahamba ngendlela eyodwa avimbela ukugeleza kwegazi emuva, isici imithambo yegazi engenaso.
I-Fungsi
Umsebenzi oyinhloko wemithambo yegazi ukuthutha igazi elinomoya-mpilo lisuka enhliziyweni liye kuzo zonke izicubu zomzimba. Umfutho ophezulu obangelwa yinhliziyo epompayo uqinisekisa ukugeleza kwegazi okusheshayo nokuphumelelayo. Umthambo omkhulu kunayo yonke, i-aorta, uthola igazi ngqo lisuka kwi-ventricle yesobunxele yenhliziyo, kuyilapho imithambo emincane isakazeka iye ezingxenyeni ezahlukene zomzimba.
Ngakolunye uhlangothi, imithambo ibuyisela igazi elingenawo umoya-mpilo enhliziyweni ukuze lifakwe umoya-mpilo ngamaphaphu. Ngenxa yokuthi igazi emithanjeni ligeleza ngokucindezela okuphansi, ama-valve ahambisana nemithambo asiza ukugcina ukugeleza komoya-mpilo ohlangothini olulodwa. I-vena cava ephezulu kanye ne-vena cava ephansi yimithambo emikhulu kakhulu, ekhipha igazi emzimbeni ongaphezulu nongaphansi iye e-atrium efanele yenhliziyo, ngokulandelana.
Izinhlobo Zemithambo Nemithambo
Imithambo yegazi ingahlukaniswa ngezinhlobo ezintathu ngokusekelwe emsebenzini wayo: imithambo yegazi enwebekayo, imithambo yegazi enemisipha, kanye ne-arterioles. Imithambo yegazi enwebekayo, njenge-aorta, inezindonga ezicebile ngemicu enwebekayo ukuze inciphise ukushaya kwenhliziyo futhi idlulisele amandla kahle. Imithambo yegazi enemisipha, njengemithambo yegazi enemisebe kanye nemithambo yegazi enemisipha, inezindonga eziningi ezinemisipha ukulawula ukusatshalaliswa kwegazi ezithweni ezithile. Imithambo yegazi enemisipha emincane kakhulu exhuma ngqo kuma-capillaries futhi ilawule ukugeleza kwegazi ezicutshini.
Imithambo ingahlukaniswa ngezinhlobo ezintathu: imithambo emikhulu, imithambo ephakathi nendawo, kanye nama-venule. Imithambo emikhulu, njenge-vena cava, inezindonga ezijiyile kuneminye imithambo ukuze ikwazi ukuthwala igazi elikhulu. Imithambo ephakathi nendawo inama-valve amaningi futhi ivame ukubandakanyeka ekubuyiseleni igazi emalungeni. Ama-venule yimithambo emincane kakhulu, ethola igazi elivela kuma-capillary bese liphuma liye emithanjeni ephakathi nendawo.
Umfutho Wegazi Nokugeleza Kwegazi
Umfutho wegazi uyisici esibalulekile esihlukanisa imithambo yegazi nemithambo yegazi. Emithanjeni yegazi, umfutho wegazi uphezulu kakhulu ngoba igazi likhishwa ngqo enhliziyweni. Umfutho wegazi ophakeme (ngesikhathi sokufinyela kwenhliziyo) kanye nomfutho wegazi ophansi (ngesikhathi sokuphumula kwenhliziyo) kulinganiswa emithanjeni yegazi, okunikeza ulwazi mayelana nempilo yomuntu yenhliziyo nemithambo yegazi.
Ngokuphambene nalokho, umfutho wegazi emithanjeni uphansi kakhulu. Ukugeleza kwegazi emithanjeni kuqhutshwa ukufinyela kwemisipha yamathambo ezungeze imithambo kanye nomfutho wangaphakathi kwesifuba okhiqizwa ngesikhathi sokuphefumula. Imithambo iphinde isizwe ngama-valve ahamba ngendlela eyodwa ukuvimbela ukugeleza kwegazi emuva, ikakhulukazi emaphethelweni aphansi, lapho amandla adonsela phansi angavimbela khona ukubuyela kwegazi enhliziyweni.
Ukubaluleka Kwempilo
Izinkinga zempilo ezithinta imithambo yegazi nemithambo yegazi zingahlukahluka kakhulu. I-atherosclerosis, isibonelo, yisimo lapho imithambo yegazi iqina futhi incipha ngenxa yokwakheka kwama-plaque, okwandisa ingozi yokuhlaselwa yinhliziyo nesifo sohlangothi. Umfutho wegazi ophakeme, noma umfutho wegazi ophakeme, nakho kuhlobene kakhulu nokusebenza kabi kwemithambo yegazi.
Izinkinga ezivamile zemithambo zihlanganisa imithambo evuvukele futhi ekhulisiwe ebangelwa ama-valve angasebenzi kahle. I-Deep vein thrombosis (DVT) yisimo esibi lapho kwakheka khona ihlule legazi emthanjeni ojulile, okungase kubangele i-pulmonary embolism uma ihlule liya emaphashini.
Isiphetho
Umehluko phakathi kwemithambo yegazi nemithambo yegazi uhlanganisa izici ezahlukahlukene zesakhiwo, ukusebenza, kanye nendawo ezibalulekile ekuqondeni ukuthi uhlelo lwenhliziyo nemithambo yegazi lusebenza kanjani. Imithambo yegazi, enezindonga zayo ezijiyile nezinwebekayo, ithwala igazi elinomoya-mpilo lisuka enhliziyweni liye emzimbeni wonke, kuyilapho imithambo yegazi, enezindonga zayo ezincane namavalvu, ithwala igazi libuyele enhliziyweni. Lezi zinhlobo ezimbili zemithambo yegazi zisebenza ngokubambisana ukuqinisekisa ukuthi umzimba uthola umoya-mpilo okwanele kanye nezakhamzimba futhi ususa kahle imfucuza.
Ukuqonda lo mehluko kubalulekile hhayi kochwepheshe bezokwelapha kuphela kodwa nakubantu abafuna ukuqonda kangcono ukuthi impilo yabo yenhliziyo nemithambo yegazi ingagcinwa noma ithuthukiswe kanjani. Ngenxa yendima ebalulekile edlalwa yimithambo yegazi nemithambo yegazi empilweni yansuku zonke, ukugcina imithambo yegazi enempilo kuyisinyathelo esibalulekile ekuvimbeleni izifo eziningi ezimbi kanye nokufeza ikhwalithi yokuphila engcono kakhulu.
