Indlela Izitsha Ezikhethekile Ezilawula Ukucindezeleka Kwegazi
Imishanguzo yizitsha zegazi ezithwala igazi okwenziwe nge-oxygen ngaphandle kwenhliziyo. Njengoba behamba phansi ngokusebenzisa inethiwekhi yokuxhumana, bahamba kancane futhi bancane njengamagatsha omuthi. Uma sehlile ngosayizi kuya kumamitha amamitha angama-300 (μm), sibhekisela kuzo njenge-arterioles.
I-Arterioles inezinhlobo eziningi ze-arteries. Ziqinile, zinezindonga ezincane kakhulu, futhi ziqukethe amaphesenti aphezulu obuhlungu obunzima.
Kodwa, futhi bakhonza omunye umsebenzi obalulekile. I-Arterioles empeleni, imithwalo yegazi elawulwa kakhulu kakhulu emzimbeni futhi ibambe iqhaza elikhulu ekukhuphukeni nasekuweleni kwegazi .
Njengengxenye, i-arterioles isabela ezinhlobonhlobo zemilayezo yamakhemikhali nezigesi ezivela ebuchosheni, amasosha omzimba kanye nesistimu ye-endocrine futhi ishintsha njalo ngobukhulu ekuphenduleni leyo miyalezo. Ngokwenza kanjalo, ukugeleza kwegazi kungasheshisa noma kuphuze, okwenza izinguquko eziningana emzimbeni wegazi.
Ukulandela ukugeleza kwegazi
Uhlelo lokujikeleza lubhekwa luvaliwe ngaphandle kokuthi igazi lingalokothi lishiye inhlanganisela yenethiwekhi yezintambo. Eyisisekelo sayo, uhlelo luqala futhi luphela enhliziyweni, luhambisa ama-molecule e-oksijeni ohambweni lwangaphandle bese luthwala i-carbon dioxide ekuhambeni kwangaphakathi.
Umzila wangaphandle uqala njengoba inhliziyo iqhuma igazi nge-aorta futhi iqhubeka igaxa njengoba igazi lenza indlela eya emincane kakhulu emithanjeni yegazi okuthiwa ama- capillaries .
Ngaphambi kwalokhu, igazi kufanele lidlule i-arterioles lapho ijubane layo lihlale lilungiswa khona. Lezi zinguquko zingenzeka kunoma yiziphi izizathu ezibandakanya ukuphakama noma ukuwa ekushiseni, izinguquko ekusebenzeni ngokomzimba, ukudla , ukucindezeleka , noma ukuvezwa kwezidakamizwa noma imithi.
Ngakho-ke, umsebenzi we-arterioles ukulawula ukucindezeleka kwegazi ukuze uhlale unomthelela futhi ungathinti ukuguquguquka.
Ngokwenza kanjalo, igazi ngeke lisaphuma njengoba lifika kuma-capillaries. Esikhundleni salokho, ukugeleza kuzoqhubeka nokuqhubeka, okuvumela ukushintshaniswa okuqhubekayo kwe-oxygen ne-carbon dioxide molecules.
Uma ukushintshaniswa sekuphelile, igazi lizokwenza uhambo olungaphakathi ngaphakathi kwenethiwekhi yezinyosi, ekugcineni libuyele enhliziyweni nge-vena cava engaphansi futhi ephakeme.
I-Arteriole Disorders
Uma umzimba usebenza ngendlela efanele, i-arterioles isiza ukuqinisekisa ukuthi umfutho wegazi uhlala ngaphansi kwemingcele evamile, enempilo. Noma kunjalo, kunezimo ezingathinta noma ezivimbela ukusebenza kwazo. Phakathi kwazo:
- I-arteriosclerosis yinkimbinkimbi, ikhuni, futhi ilahlekelwa ukuqina kwezindonga eziphethe. Le nqubo ivimbela ikhono le-arteriole lokulawula ukugeleza kwegazi futhi livumela ukufakwa okuqhubekayo kwe-plaque ne-cholesterol ezindongeni zokugqoka. Izimbangela ezintathu eziyinhloko ze-arteriosclerosis yi-cholesterol ephakeme, i-triglycerides ephakeme, ukubhema ugwayi, ngisho nokucindezela kwegazi ngokwayo.
- I-stenosis ye- arteriial is the narrowing of the arteries. Lokhu kungabangelwa yinoma iyiphi inamba yezinto ezifaka ukungcola, ukubhema, isifo sikashukela, ukutheleleka, nokukhubazeka kokuzalwa. Ngokuqondile, ukuvinjelwa okuqhubekayo kwemithambo yegazi ngenxa yokungcola noma ukutheleleka okungapheli kungaholela ekuqotheni okuqhubekayo (fibrosis) wezicubu zomzimba.
- I-Arteritis ukuvuvukala kwezindonga zokugcoba ngaphakathi nangaphansi kwesikhumba, ngokuvamile kuhlotshaniswa nezifo ezizimele . Ukuvuvukala kwezindonga zokugcoba kuholela ekunciphiseni kwegazi. Isibonelo esihle yi- giant cell arteritis (i-GCA) ethinta amagatsha we-artery carotid yangaphandle entanyeni. Nge-GCA, ukugeleza kwegazi okukhubazekile kungabangela izimpawu zesifo sekhanda, izinguquko zombono, ukulahleka kombono, nokubuhlungu komhlathi lapho kuhlafuna.
Izwi elivela
Uma uthola ukuthi une-high blood pressure, kudingeka udinga ukunakekelwa udokotela ongakubeka emithonjeni yokulwa negciwane. Nakuba ungase uzwe kahle futhi ungenayo izimpawu, ukutholakala kwengcindezi ephezulu yegazi kungandisa ingozi yokuhlaselwa yinhliziyo nokushaywa yisifo.
Yingakho ukucindezelwa kwegazi okuphakeme kubizwa ngokuthi "umbulali othulile."
> Imithombo:
> Lehmann, M. no Schmieder, R. "Ukulungiswa kwemithambo emincane ye-retinal e-hypertension," u- Am J Hypertens. 2011; 24 (12): 1267-73. I-DOI: 10.1038 / ajh.2011.166.
> Nobel, A .; Johnson, R .; Bass, P. et al. (2010) Isistimu Yezinhliziyo (Second Ed.) . ILondon: Churchill Livingstone / Elsevier. I-ISBN: 9780702050824.