I-Anatomy kanye ne-Physiology yesibindi
Isibindi singesinye sezitho ezinkulu nezibaluleke kakhulu emzimbeni womuntu. Sivame ukwaziwa ngendima yaso "ekususeni ubuthi emzimbeni," kodwa imisebenzi yaso ibanzi kakhulu: ukulawula ukusebenza kwezakhamzimba, ukukhiqiza i-bile yokugaya ukudla, ukugcina amandla agciniwe, ukukhiqiza amaprotheni abalulekile ekujiyeni kwegazi, ngisho nokudlala indima ohlelweni lokuzivikela komzimba. Ukuze siqonde ukuthi kungani isibindi sibaluleke kangaka ekusindeni, sidinga ukuhlola ukwakheka komzimba (isakhiwo) kanye ne-physiology (indlela esisebenza ngayo) yalesi sitho ngokuphelele.
Ukwakheka Kwesibindi
Ngokwesimo somzimba, isibindi sitholakala engxenyeni engenhla kwesokudla yesisu, ngaphansi nje kwe-diaphragm. Ingxenye encane yaso ifinyelela ohlangothini lwesobunxele. Kwabantu abadala, isibindi sinesisindo esingama-kg angu-1,2–1,5, okwenza sibe yisitho esiqinile esikhulu kunazo zonke emzimbeni. Ubuso besibindi bubushelelezi futhi bumbozwe yi-Glisson's capsule, i-connective tissue sheath esiza ukugcina isimo sesitho futhi ihlinzeke ngendlela yokuhamba kwemithambo yegazi kanye ne-bile ducts.
Isibindi sihlukaniswe ngama-lobes amaningana. Ngokwemvelo, ama-lobes angakwesokudla nakwesobunxele aqashelwa njengokuhlukaniswa okuyinhloko, kanti ama-lobes e-caudate nama-quadrate aphansi kakhulu. Kodwa-ke, ekwelashweni kwezokwelapha kwanamuhla, ukuhlukaniswa okubaluleke kakhulu ukuhlukaniswa okusebenzayo okusekelwe ekugelezeni kwegazi kanye nemigudu ye-bile (ukuhlukaniswa kwesibindi). Lolu hlelo lokuhlukaniswa luvame ukubizwa ngokuthi ukuhlukaniswa kukaCouinaud, okuhlukanisa isibindi sibe yizingxenye eziyisishiyagalombili, ngasinye sinokunikezwa kwegazi okuzimele kanye nokuphuma kwe-bile. Lokhu kuhlukaniswa kuwusizo kakhulu ekuhlinzeni kwesibindi, njengokususwa kwesimila, njengoba kuvumela ukususwa kwezindawo ezithile ngaphandle kokuphazamisa umsebenzi ojwayelekile.
Imithambo Yegazi Lesibindi: Iyingqayizivele Futhi Icebile Ngokugeleza
Ukungafani kwesibindi kulele ekuhlinzekeni kwaso igazi eliphindwe kabili. Isibindi sithola igazi ku:
1. Umthambo we-hepatic portal (cishe u-70-75% wokugeleza kwegazi), othwala igazi elicebile ngezakhamzimba lisuka emgudwini wokugaya ukudla, i-pancreas, kanye ne-spleen.
2. Umthambo wesibindi (cishe u-25–30% wokugeleza kwegazi), othwala igazi elinomoya-mpilo elivela enhliziyweni.
Igazi elivela kule mithombo emibili lixubana kuma-sinusoid esibindi, ama-capillary akhethekile anama-lumens abanzi avumela ukushintshaniswa kwezinto okuphumelelayo. Ngemva kokudlula kuma-sinusoid, igazi ligeleza liye emthanjeni ophakathi, bese lingena emthanjeni wesibindi, bese ekugcineni liye e-vena cava engaphansi ukuze libuyele enhliziyweni.
Isakhiwo se-Microscopic: Ama-Lobule namaSeli Abalulekile
Iyunithi encane kakhulu yesibindi yi-hepatobule, enesimo esilinganayo nesinomugqa ophakathi nendawo. Emakhoneni e-lobule kukhona i-portal triad, equkethe amagatsha e-portal vein, amagatsha e-hepatic artery, kanye ne-bile ducts. Lokhu kuhlelwa kubonisa umqondo "wokujikeleza kwegazi nokuphuma kwamanzi" kwesibindi: igazi ligeleza lisuka ku-portal triad liye emthanjeni ophakathi, kuyilapho i-bile igeleza ngakolunye uhlangothi lisuka kuma-hepatocytes liye emithanjeni ye-bile.
Amaseli ayinhloko esibindi ama-hepatocytes, akha amapuleti eseli futhi ahilelekile cishe kuyo yonke imisebenzi ye-metabolic. Ngaphezu kwama-hepatocytes, kukhona:
– Amaseli e-Kupffer, angama-macrophage esibindi agwinya amabhaktheriya, amaseli abomvu egazi amadala, kanye nezinhlayiya zangaphandle.
– Amaseli e-Stellate (Ito), agcina i-vitamin A; uma evuselelwa njalo, angakhiqiza i-collagen futhi abangele i-fibrosis.
– Amaseli endothelial e-sinusoidal, anezimbobo, okwenza kube lula ukushintshanisa izinto phakathi kwegazi nama-hepatocytes.
I-Physiology Yesibindi
I-physiology yesibindi ihlanganisa uchungechunge oluyinkimbinkimbi lwezinqubo ezigcina ibhalansi yangaphakathi yomzimba (i-homeostasis). Nazi ezinye zemisebenzi ebaluleke kakhulu yesibindi.
1. Ukukhiqizwa Kwenyongo Nokukhishelwa Kwayo
Inyongo ikhiqizwa ama-hepatocyte bese ithuthwa nge-bile canaliculi iye emgudwini wesibindi. Ivame ukugcinwa futhi igxile enyongweni ngaphambi kokuba ikhishwe iye e-duodenum. Inyongo iqukethe usawoti wenyongo, i-bilirubin, i-cholesterol, ama-phospholipid, nama-electrolyte. Imisebenzi yayo eyinhloko yile:
– I-Emulsifying fat ukuze igaywe kalula yi-enzyme ye-lipase.
– Kusiza ekumunceni amavithamini ancibilikayo emafutheni (A, D, E, K).
- Isebenza njengendlela yokukhipha i-bilirubin ne-cholesterol.
2. Ukuguqulwa Kwe-carbohydrate: Ukugcina Amazinga Kashukela Egazini
Isibindi sisebenza njengesiqinisi se-glucose egazini. Uma amazinga e-glucose ephezulu ngemva kokudla, isibindi sigcina i-glucose ngesimo se-glycogen (i-glycogenesis). Uma amazinga e-glucose ehla, isibindi siphula i-glycogen ibe yi-glucose (i-glycogenolysis). Uma izitolo ze-glycogen ziphela, isibindi sikhiqiza i-glucose entsha evela kuma-amino acid, i-lactate, noma i-glycerol ngokusebenzisa i-gluconeogenesis. Le ndlela iqinisekisa ukunikezwa kwamandla njalo ebuchosheni nakwezinye izicubu.
3. Ukuguqulwa Kwamafutha: I-Cholesterol nama-Lipoprotein
Isibindi siyisikhungo se-lipid metabolism. Lesi sitho:
- Ihlanganisa i-cholesterol kanye ne-phospholipids.
– Kwakha ama-lipoprotein (isib. i-VLDL) ukuthutha amafutha egazini.
– Oxidize amafutha acid njengomthombo wamandla.
– Iguqula ama-carbohydrate namaprotheni amaningi abe ama-triglycerides ukuze agcinwe.
Ukungalingani kule nqubo kungabangela ukuqongelela kwamafutha esibindini (i-steatosis), okungaqhubekela phambili ekuvuvukeni nasekulimeni okwengeziwe uma kuqhubeka.
4. Ukuguqulwa Kwamaprotheni: I-Albumin kanye Nezinto Ezibangela Ukuqhekeka Kwama-Clotting
Isibindi sakha amaprotheni ahlukahlukene abalulekile e-plasma, okuhlanganisa:
– I-Albumin, egcina ingcindezi ye-osmotic yegazi futhi ithutha izinto ezahlukahlukene (ama-hormone, izidakamizwa, ama-fatty acid).
– Izinto ezibangela ukujiya kwegazi (isib. i-fibrinogen, i-prothrombin, izinto ezibangela VII, IX, X).
– Amaprotheni okuthutha afana ne-transferrin kanye ne-ceruloplasmin.
Ngaphezu kokwenziwa, isibindi silawula nokusetshenziswa kwama-amino acid. I-ammonia enobuthi, umkhiqizo wokuqhekeka kwama-amino acid, iguqulwa ibe yi-urea ngomjikelezo we-urea bese ikhishwa ngezinso.
5. Ukususa Ubuthi Ezidakamizwani kanye Nokuguqulwa Kwezinto Eziphilayo
Omunye wemisebenzi yesibindi eyaziwa kakhulu ukuguqula izinto eziyingozi zibe izinhlobo ezikhishwa kalula. Le nqubo yenziwa ngama-enzyme, ikakhulukazi uhlelo lwe-cytochrome P450, olusebenzisa izidakamizwa, utshwala kanye nobuthi. Ukususwa kobuthi ngokuvamile kwenzeka ngezigaba ezimbili:
– Isigaba I: ukushiswa kwe-oxidation, ukunciphisa, noma i-hydrolysis, okushintsha isakhiwo sento.
– Isigaba II: ukuhlangana (isibonelo ne-glucuronide noma i-sulfate), kwenza into incibilike emanzini ukuze ikhishwe kalula enyongweni noma emchameni.
Ngakho-ke, ukusebenza kwesibindi okuphazamisekile kungabangela ukuthi izidakamizwa zihlale emzimbeni isikhathi eside futhi kwandise ingozi yemiphumela emibi.
6. Ukugcinwa Kwezinto Ezibalulekile
Isibindi sisebenza njengesitolo sokugcina:
– I-Glycogen njengenqolobane yamandla.
– Amavithamini: A, D, E, K, kanye nevithamini B12.
– Amaminerali: ikakhulukazi insimbi (ngesimo se-ferritin) kanye nethusi.
Lezi zigcini zenza umzimba ukwazi ukumelana nezikhathi zokuntuleka kokudla okunempilo noma izimo zokucindezeleka kwe-metabolic.
7. Umsebenzi Wokuzivikela Emzimbeni kanye Nokuhlunga Igazi
Ngamaseli e-Kupffer, isibindi sihlunga igazi elivela emgudwini wokugaya ukudla, elicebile ngamagciwane kanye nama-endotoxin. Le ndlela ibalulekile ngoba amathumbu angumthombo omkhulu wama-microorganisms kanye nezinto zakwamanye amazwe. Ngakho-ke, isibindi sisebenza "njengendawo yokuhlola" ngaphambi kokuba igazi lingene emgudwini wokujikeleza kwegazi.
Ukuhlanganiswa kwe-Anatomy kanye ne-Physiology: Kungani Isakhiwo Sisekela Umsebenzi
Isakhiwo esinezimbobo zama-sinusoid sivumela ama-hepatocyte ukuthi athole izakhamzimba, izidakamizwa, kanye nobuthi egazini ngempumelelo. Ukugeleza kwegazi okuvela emthanjeni we-portal kuchaza ukuthi kungani noma yini emuncwa emathunjini idlula esibindini kuqala (umphumela wokudlula kokuqala), okuthinta ukusebenza kahle kwemithi yomlomo. Okwamanje, uhlelo lwe-bile canalicular, olugeleza ngendlela ephambene nokugeleza kwegazi, luqinisekisa ukuthi imikhiqizo engcolile efana ne-bilirubin ingaqoqwa futhi ikhishwe.
I-Penutup
Isibindi siyisitho esisebenza ngezindlela eziningi esinokwakheka kwaso okuklanyelwe ngokukhethekile ukusekela izindima zaso ezibanzi. Kusukela ezakhiweni ezinkulu njengezindawo ezincane nezincane kuya kumayunithi amancane njengezindawo ezincane nezincane, konke kunegalelo ekhonweni lesibindi lokulawula ukusebenza kwe-metabolism, ukukhiqiza i-bile, ukugcina izinto ezibalulekile, nokuhlanza umzimba. Ukuqonda ukwakheka kwesibindi kanye nokusebenza kwaso akubalulekile nje kuphela emkhakheni wezokwelapha, kodwa futhi kusiza umphakathi ukuqaphela ukuthi ukugcina impilo yesibindi—ngokudla okulinganiselayo, umsebenzi womzimba, ukugwema utshwala ngokweqile, kanye nokusebenzisa imithi ngokuhlakanipha—kuwukutshalwa kwezimali okukhulu empilweni iyonke.
