Ubuchopho yisitho esiyinhloko sohlelo lwemizwa oluphakathi, bukhiqiza izindlela zokuhumusha imininingwane, izimpendulo kanye nokulawulwa kwezinhlaka. Lesi sakhiwo sibonakala ngokuthi asinaso isistimu yokugcina amandla esivumela ukuthi sisebenze, yingakho sincike ngokuphelele ekugelezeni kwegazi. Ucwaningo lwezokwelapha luthole ukuthi kuthatha imizuzwana eyi-10 kuphela yokungabikho noma ukwehla kokugeleza kwegazi (ischemia), ukuze umuntu alahlekelwe ukwazi, futhi kusuka kumasekhondi ayi-15 kuye kwangama-20, ukuze sikwazi ukubona imiphumela ebalulekile yesibambiso kumuntu ngamunye.
Ngenxa yalokhu, umzimba wethu kuveza isakhiwo esakhiwe ngohlelo lwendandatho olumise okwendandatho, Umsebenzi wawo oyinhloko ukuguqula ingcindezi ekushintsheni emzimbeni, kuvimbele ukugeleza kwegazi kuye ebuchosheni kungashintshwa. Le nethiwekhi yemithambo, eyaziwa ngokuthi i-polygon kaWillis.
Yini i-polygon futhi yakhiwe kanjani?
Ukusebenza kwalesi sakhiwo kunqunywe udokotela wezinzwa waseNgilandi uThomas Willis, okwathi ngekhulu le-XNUMX waba ngowokuqala ukukhomba ukusebenza kwaso, nokubaluleka kwaso ngohlelo lobuchopho. Siqukethe isakhiwo, esisendaweni leptomeningeal (subarachnoid) futhi kuyindawo yesikhala sobuchopho esinqunyelwe yi arachnoid (meninge Lesisemkhatsini) kanye futhi mater (meninge yangaphakathi). I-polygon kaWillis, inokwakheka kwendandatho, futhi yakhiwe ngohlu lwemithambo nemithambo yegazi, umsebenzi wayo omkhulu ukulawula ukugeleza kwegazi kuya ezithweni zesistimu yezinzwa emaphakathi, njengobuchopho nobuchopho.
Imithambo emikhulu eyisithupha, enesibopho sokuhambisa igazi liye ebuchosheni, ihlanganiswe ngendlela efuna ukwazi, eye yafaniswa neheksagoni, yingakho i-polygonal denotation yesakhiwo seWillis. Yize ongoti bakule ndawo bekugcizelele ukuthi kujwayelekile kwezinye iziguli ezingenakho ukuthambekela kwe-ischemic, ukuthola lesi sakhiwo singaphelele. Ngezansi sibiza imithambo eyinhloko eyakha lesi sakhiwo:
Imithambo eyinhloko eyakha isiyingi sikaWillis:
Ibekwe kusekethe evaliwe, lokho okubizwa ngokuthi iheksagoni kaWillis ikakhulukazi yakhiwe yimithambo elandelayo:
Imithambo yokuxhumana engaphambili (ACA): Ku indawo ejwayelekile yobuchopho, lo mthambo uthola umsuka wawo, uxhuma imithambo emibili yangaphakathi yobuchopho, enobude obusondele ku-4 kuye ku-5 mm, yize kunzima ukuqagela, ngoba ukuhlukahluka okuningi ngosayizi wayo osondele kuye kwabonwa. Uthando oluxhunywe kulo mthambo luholela ekuguqulweni emkhakheni wokubuka.
Imithambo yokuxhumana engemuva kwangemuva (PCA): Umthambo wokuxhumana oqhamuka emthanjeni wangaphakathi we-choroidal, futhi kungumsebenzi wawo ukwenza ukuxhumana phakathi kwemithambo emi-3 yesikhala esifanayo sobuchopho. I-pathology ejwayelekile kakhulu engakhula kulesi sakhiwo i-aneurysm yangemuva yokuxhumana nomthambo.
Umthambo we-ophthalmic: Kusuka ku- izinqubo zangaphakathi ze-clinoid, ukondla imizwa ye-optic. Kwakha igatsha lesibambiso lomthambo wangaphakathi we-carotid.
Umthambo we-carotid wangaphandle: Ingenye yemithambo eyinhloko etholakala ebuchosheni bomuntu, evela ku-carotid ejwayelekile. Lona ngumthambo esivumela ukuthi sithathe i-carotid pulse, futhi uhlukanise phakathi kokuhlukaniswa okubalulekile okuyisithupha ngokuya kwegazi ezinhlakeni eziphakeme.
Umthambo weBasilar: Umthambo odumile oqhamuka enhlanganweni yomgogodla yohlangothi lwangakwesokudla nangakwesobunxele, umsebenzi walo ukuhambisa igazi elinomoya-mpilo liye ebuchosheni.
Ukubaluleka kwegazi elinomoya-mpilo ebuchosheni
Zonke izitho zidinga ukugeleza kwegazi ukuze zisebenze kahle, ngoba lolu ketshezi olokuthutha okuyinhloko lwezakhi zomzimba nezakhi eziyisisekelo, okudingeka kuzo zonke izakhiwo ezibalulekile ukuze zikhule kahle. Endabeni yobuchopho, ukunikezwa komoya-mpilo odluliswa yigazi kuyaziswa kakhulu futhi kuyakuvumela ukuthi kusebenze. Futhi ukubaluleka kwayo kuyancomeka ekutheni imizuzwana embalwa nje ngaphandle kokutholakala okuvamile ketshezi olubalulekile ingahumushela ekuthandeni okubalulekile ezindaweni zezimoto nezokuqonda zomuntu (kuya ngendawo lapho ukwehluleka kwenzeka khona).
Indlela yokusebenza kweheksagoni kaWillis
Ububanzi beWillis ngokuyinhloko bungumsebenzi wokwenza i- ukusakazwa kwesibambiso, okuyindlela yokulondolozwa ezingeni lezakhiwo ezinkulu zohlelo lwemizwa oluphakathi. Ukujikeleza kwesibambiso kubhekisa ekugelezeni kwegazi okwenziwa kwenziwe ezimeni lapho ukugeleza kuguqulwa khona (ukwehla noma ukuyeka), futhi yize isenzo saso singakwazi ukubuyisela umsebenzi wemithambo yegazi ebhekele ukunisela, Lolu hlelo oluphuthumayo luvumela ukusebenza okujwayelekile ukwelulwa isikhathi esilinganiselwe, esiza ukunciphisa imiphumela emibi, kuyilapho isiguli sithola usizo lwezokwelapha.
Lapho kwenzeka ukuvaleka kwemithambo yegazi, okuthinta ukuzinza kokugeleza kwegazi ezakhiweni zobuchopho, ukwanda kokumelana nokugeleza kuyabonakala emithanjeni ye-carotid ne-vertebral, yingakho ukwehla kwengcindezi ezingeni kwenzeka. ye-Willis polygon eqala isenzo sokunciphisa, ngomzamo wokwelula ukusebenza okuhle, isikhathi eside ngangokunokwenzeka. Kukhula ubukhulu be- i-anastomosis, mkhulu umnikelo wesibambiso wezakhiwo zemithambo engabandakanyeki kulokhu kuvalwa. Ngaphansi kwezimo ezijwayelekile, le mibhobho ehlukile ingahlala ingasebenzi, noma isetshenziswe kakhulu, lapho kungabonakali khona ukugeleza kwegazi, kepha kunalokho kwenziwa ukunyakaza kwegazi, okuhlose ukugcina amandla esakhiwo, ngaleyo ndlela kugwenywe izifo ezifana ne-thrombosis .
Lapho ukunikezwa kwegazi lesibambiso kunganele ukwanelisa isidingo sokunisela endaweni enikezwe ngegazi ngumthambo ophazamisekile, izindlela zesibili ezifana ukuvuleka kwemikhumbi yokumelana.
Njengoba ubona, umzimba womuntu uqukethe uhlelo oluyinkimbinkimbi, olwakhiwa izakhiwo eziqinisekisa ukulinganiswa kokusebenza kwalo.
Izifo ezihlangene
Ukuncipha, ukuqina nokuvinjelwa kwemithambo yegazi kuyimbangela eyinhloko yezifo ezakhiwe ezingeni lesistimu yezinzwa emaphakathi, esebenze ukusebenza kwesakhiwo semithambo kaWillis. Izifo eziyinhloko ezenziwa yizinkinga zomzimba zibalwe ngezansi:
I-thrombosis: Siqukethe ihlule legazi elenza ukuvinjelwa ezingeni lemithambo, okungaholela ekuqhekekeni kwalo, umphumela oqondile okuwukopha.
Ama-Aneurysms: Iqukethe indawo ebuthakathaka yomthambo wegazi, eholela ekuvukeleni kwayo, kuyisimo esibi esingaholela ekufeni kwesiguli, ngoba ezimweni zokukhuphuka kwengcindezi yegazi, ukuqhekeka komkhumbi kungenzeka. Ama-aneurysms amaningi (ngokusho kwedatha yomtholampilo engaphezu kuka-80%) avela engxenyeni engaphambili yombuthano kaWillis, odokotela abaningi baphethe ngokuthi ingxenye yezakhi zofuzo iyabuthinta lobu buhlobo.
Ingozi ye-Cerebrovascular (CVA): Kwakha isifo senhliziyo noma isifo sohlangothi, okuholela ekufeni kweziguli eziningi ezikutholayo.