Ingqondo yeyona nto iphambili kwinkqubo yovalo, ivelisa iindlela zokuguqula ulwazi, iimpendulo kunye nokulawulwa kwezakhiwo. Olu lwakhiwo luphawulwa yinto yokuba ayinayo inkqubo yokugcina amandla evumela ukuba isebenze, yiyo loo nto ixhomekeke ngokupheleleyo ekuhambeni kwegazi. Izifundo zonyango ziye zafumanisa ukuba kuthatha kuphela imizuzwana eyi-10 yokungabikho okanye ukunciphisa ukuhamba kwegazi (ischemia), ukuba umntu alahlekelwe yingqondo, nakwimizuzwana eyi-15 ukuya kwengama-20, ukuze siqwalasele iziphumo ezibambekayo zomntu ngamnye.
Ngokwale nto, imizimba yethu inesakhiwo esenziwe ngenkqubo yemithambo emise okomsesane, Umsebenzi wawo ophambili kukutshintsha utshintsho koxinzelelo emzimbeni, ukuthintela ukuhamba kwegazi ukuya kwingqondo kuguqulwe. Inethiwekhi yemithambo, eyaziwa ngokuba yi-polygon kaWillis.
Yintoni ipoligoni kwaye yenziwe njani?
Intshukumo yolu lwakhiwo yagqitywa yingcali ye-English neurologist uThomas Willis, owathi ngenkulungwane ye-XNUMX waba ngowokuqala ukubonisa ukusebenza kwayo, kunye nokubaluleka kwayo ngokulandelelana kwinkqubo yobuchopho. Inesakhiwo, esime emajukujukwini eyenyani (subarachnoid) kwaye yindawo yengqondo ebekelwe indawo ngu zintsi (meninge eliphakathi) kunye ngokufanayo mater (i-meninge yangaphakathi). I-polygon kaWillis, inesangqa esimile, kwaye senziwe ngeseti yeenqanawa kunye nemithambo, umsebenzi wayo ophambili kukulawula ukuhamba kwegazi kumalungu enkqubo ye-nervous system, enje ngengqondo kunye ne-encephalon.
Imithambo yegazi emithandathu, inoxanduva lokuhambisa igazi liye kwingqondo, zimanyene ngendlela enomdla, ethe yafaniswa neheksagoni, yiyo loo nto i-polygonal denotation Ubume beWillis. Nangona iingcali zommandla zigxininise ukuba kuqhelekile kwezinye izigulana ngaphandle kothando lwe-ischemic, ukufumana olu lwakhiwo lungaphelelanga. Apha ngezantsi sichaza eyona mithetho iphambili yenza olu lwakhiwo:
Imithambo ephambili eyenza isangqa sikaWillis:
Ibekwe kwisekethe evaliweyo, ebizwa ngokuba yiheksagoni kaWillis ubukhulu becala yenziwe ngezi mithambo zilandelayo:
Imithambo yokunxibelelana ngaphambili (ACA): Kulo ummandla oqhelekileyo yobuchopho, lo mthambo ufumana imvelaphi yawo, udibanisa imithambo emibini yobuchopho engaphakathi, enobude obuqikelelweyo be-4 ukuya kwi-5 mm, nangona kunzima ukuqikelela, kuba ukwahluka okuninzi kubungakanani bayo obuqikelelweyo kuye kwabonwa. Ukuthandana okunxulunyaniswe nalo mthambo kukhokelela kutshintsho kumhlaba obonwayo.
Imithambo enxibelelana ngasemva (PCA): Ngumthambo wonxibelelwano ovela kwimithambo yangaphakathi ye-choroidal, kwaye luxanduva lwayo ukuseka unxibelelwano phakathi kwemithambo emi-3 yecebral hemisphere efanayo. Esona sifo siqhelekileyo sixhaphakileyo esinokukhula kolu lwakhiwo ngumva we-artery aneurysm.
Umthambo weOphthalmic: Isuka kwi iinkqubo zangaphakathi ze-clinoid, ukondla iimbilini zamehlo. Yenza isebe lesibambiso semithambo yangaphakathi ye-carotid.
Umthambo wecarotid wangaphandle: Ngomnye wemithambo ephambili ebekwe kwingqondo yomntu, evela kwi-carotid eqhelekileyo. Lo ngumthambo osivumela ukuba sithathe ukubetha kwe-carotid, kwaye wona amasebe aba ziindawo ezintandathu ezibalulekileyo ngokubhekisele kunikezelo lwegazi kwizakhiwo eziphezulu.
Umthambo weBasilar: Ngumthambo odumileyo osuka kwindawo yokudibana kwe-vertebral yecala lasekunene nelasekhohlo, umsebenzi walo kukuhambisa igazi elinomoya-mpilo uye kwingqondo.
Ukubaluleka kwegazi elinomoya-mpilo kwingqondo
Onke amalungu afuna ukuhamba kwegazi ukuze asebenze ngokufanelekileyo, kuba olu lwelo lolona thutho luphambili lwezakhamzimba kunye nezinto ezisisiseko, ezifuneka kuzo zonke izinto ezibalulekileyo kuphuhliso lwazo. Kwimeko yengqondo, ukuhanjiswa kweoksijini ehanjiswa ligazi kuyabulelwa kakhulu kwaye kuyivumela ukuba isebenze. Kwaye ukubaluleka kwayo kuyancomeka kwinto yokuba imizuzwana nje embalwa ngaphandle konikezelo oluqhelekileyo lolwelo olubalulekileyo lunokutolika lube luthando olubalulekileyo kwiimoto nakwimimandla yokuqonda yomntu (kuxhomekeke kwindawo apho kusilela khona).
Indlela yokusebenza kwehexagon kaWillis
Uluhlu lweWillis ikakhulu luxanduva lwalo Ukujikeleza kwesibambiso, eyenza indlela yokulondolozwa kwinqanaba lezinto eziphambili zenkqubo ye-nervous system. Ukujikeleza kwezibambiso kubhekisa kukuhamba kwegazi okwenziwa kwimeko apho ukutshintsha kuguquka khona (ukwehla okanye ukuyeka), kwaye nangona isenzo sayo singenakho ukubuyisela umsebenzi weemithambo ezinoxanduva lokunkcenkceshela, Le nkqubo kaxakeka ivumela ukusebenza kwesiqhelo ukuba kwandiswe ixesha elimiselweyo, enceda ukunciphisa iziphumo ezibi, ngelixa isigulana sifikelela kunyango.
Xa imeko ye-vascular occlusion isenzeka, echaphazela uzinzo lokuhamba kwegazi kulwakhiwo lobuchopho, ukwanda kokumelana nokuhamba kuyajongwa kwimithambo ye-carotid kunye ne-vertebral, yiyo loo nto ukwehla koxinzelelo kwinqanaba lenzeka. ye-Willis polygon eqala ukuthambisa isenzo, ukuzama ukwandisa ukusebenza okuhle, elona xesha lide lokwenzeka. Ubukhulu bukhulu be i-anastomosis, elikhulu igalelo lesibambiso sezinto ze-vascular ezingabandakanyekanga ekungeneni. Phantsi kweemeko eziqhelekileyo, ezi conduits zinokuhlala zingasebenzi, okanye zisetyenziswe kakhulu, apho kungaphumi gazi, kodwa endaweni yoko kuhamba igazi, elijolise ekugcineni ubume besakhiwo, ngaloo ndlela kuthintelwe i-pathologies enjenge-thrombosis .
Xa ukunikezelwa kwegazi lesibambiso kungonelanga ukwanelisa imfuno yokunkcenkceshela kummandla owawunikezelwe ngegazi ngumthambo ophazamisayo, iindlela ezizezinye ezinje Ukuhlanjululwa kweenqanawa zokumelana.
Njengokuba ubona, umzimba womntu uqukethe inkqubo entsonkothileyo, eyenziwe ngamacandelo aqinisekisa ukusebenza ngokulingeneyo.
Izifo ezinxulumene noko
Ukunciphisa, ukuqina kunye nokuphazamiseka kwemithambo yeyona nto ingunobangela wezifo eziphuhliswe kwinqanaba lenkqubo ye-nervous system, esebenze ukusebenza kwesakhiwo se-Willis. Ezona zinto ziphambili ziphambili ziveliswe ngezantsi:
I-Thrombosis: Iqukethe i-clot yegazi eyenza ukuphazamiseka kwinqanaba leemitha, ezinokukhokelela ekuqhekekeni kwayo, umphumo othe ngqo woko kuphuma kwegazi.
Iimpawu: Inendawo ebuthathaka yomthambo wegazi, ekhokelela kukudumba kwayo, yimeko enokubangela ukufa kwesigulana, kuba kwimeko zokonyuka koxinzelelo lwegazi, ukuvela kwenqanawa kunokubakho.. Uninzi lwee-aneurysms (ngokweedatha yeklinikhi enkulu kune-80%) zenzeka kwinxalenye engaphambili yesangqa seWillis, oogqirha abaninzi baye bagqiba kwelokuba icandelo lemfuza liyabuchaphazela obu budlelwane.
Ingozi yeCerebrovascular (CVA): Yenza ukuhlaselwa yintliziyo okanye ukubetha, okukhokelela ekufeni kwezigulana ezininzi ezinamava.