Lub siab tsim cov kua tsib li cas
Lub siab yog ib qho ntawm cov kabmob uas tibneeg ua haujlwm ntau tshaj plaws hauv lub cev tib neeg. Ntxiv rau nws lub luag haujlwm hauv kev tshem tawm cov tshuaj lom hauv lub cev, khaws cia lub zog, thiab kev tswj hwm kev zom zaub mov, lub siab kuj ua haujlwm tseem ceeb, feem ntau tsis quav ntsej,: tsim cov kua tsib. Cov kua tsib yog cov kua dej zom zaub mov uas tseem ceeb rau kev pab lub cev zom cov rog thiab nqus qee yam vitamins. Cov txheej txheem ntawm kev tsim cov kua tsib tsis yog ib qho txheej txheem yooj yim; nws cuam tshuam nrog ntau yam txheej txheem ntawm lub cev, txij li theem cellular mus rau lub cev ntawm cov kua tsib. Tsab xov xwm no tham txog seb lub siab tsim cov kua tsib li cas, nws cov khoom, nws mus rau txoj hnyuv li cas, thiab vim li cas cov txheej txheem no tseem ceeb rau kev noj qab haus huv.
Bile yog dab tsi thiab vim li cas nws thiaj tseem ceeb?
Cov kua tsib yog cov kua ntsuab daj uas lub siab tsim tawm tas li . Nws lub luag haujlwm tseem ceeb yog ua kom cov rog sib xyaw ua ke - rhuav lawv ua cov tee me me - kom cov enzymes zom zaub mov (lipases) ua haujlwm tau zoo dua. Yog tsis muaj cov kua tsib, kev zom cov rog yuav tsis zoo, ua rau lub cev nyuaj rau nqus cov roj fatty acids thiab cov vitamins uas yaj hauv cov rog xws li cov vitamins A, D, E, thiab K.
Ntxiv rau kev pab zom zaub mov, cov kua tsib kuj ua haujlwm ua txoj hauv kev rau kev tshem tawm qee yam khoom pov tseg. Piv txwv li, bilirubin (ib yam khoom tawg ntawm hemoglobin), cov roj cholesterol ntau dhau, thiab qee yam khoom siv metabolic thiab tshuaj tuaj yeem raug tso tawm los ntawm cov kua tsib. Yog li ntawd, cov kua tsib tsis yog tsuas yog koom nrog kev zom zaub mov xwb tab sis kuj koom nrog lub cev "kev huv si" metabolic.
Cov khoom tseem ceeb ntawm cov kua tsib
Cov kua tsib tsis yog tsuas yog "dej zom zaub mov xwb," tab sis yog ib qho sib xyaw ua ke uas muaj cov hauv qab no:
1. Cov ntsev ntawm cov kua tsib: yog cov kua tsib uas ua los ntawm cov roj cholesterol. Lawv yog cov khoom tseem ceeb hauv kev sib xyaw cov rog.
2. Phospholipids (tshwj xeeb yog lecithin): pab tsim cov micelles nrog cov ntsev bile, ua rau kev nqus roj yooj yim.
3. Cov roj cholesterol: Qee cov roj cholesterol raug tso tawm hauv cov kua tsib. Yog ntau dhau tuaj yeem ua rau muaj pob zeb hauv lub zais zis.
4. Bilirubin: ib yam xim uas tshwm sim los ntawm kev tawg ntawm cov qe ntshav liab, uas ua rau cov kua tsib muaj xim.
5. Cov electrolytes thiab dej: ua rau cov kua tsib ua kua ntau dua kom nws ntws tau yooj yim los ntawm cov kav dej kua tsib.
6. Cov protein thiab lwm yam khoom: suav nrog qee cov khib nyiab metabolic thiab cov tshuaj uas yuav tsum tau tso tawm.
Cov khoom sib xyaw ntawm cov kua tsib tuaj yeem hloov pauv nyob ntawm lub cev mob, kev noj zaub mov, thiab kev ua haujlwm ntawm cov tshuaj hormones zom zaub mov.
Leej twg "ua" cov kua tsib hauv lub siab?
Cov kua tsib yog tsim los ntawm cov hlwb ntawm daim siab hu ua hepatocytes. Cov hepatocytes yog cov feem ntau ntawm cov nqaij ntawm daim siab thiab ua haujlwm zoo li cov chaw tsim tshuaj biochemical. Lawv noj cov khoom siv raw los ntawm cov ntshav, ua kom tiav, thiab tom qab ntawd tsim cov kua tsib, uas raug thauj mus los ntawm cov raj me me hauv daim siab.
Ntxiv rau cov hepatocytes, kuj tseem muaj cov hlwb epithelial hauv cov kav dej kua tsib hu ua cholangiocytes. Cholangiocytes tsis tsim cov kua tsib los ntawm kos zoo li cov hepatocytes, tab sis lawv "hloov kho" cov kua tsib - piv txwv li, ntxiv dej thiab bicarbonate - kom qhov ntim thiab cov khoom ntawm cov kua tsib tuaj yeem hloov kho kom tau raws li qhov xav tau ntawm kev zom zaub mov.
Cov theem ntawm lub siab tsim cov kua tsib
1. Kev tsim cov kua qaub cov roj cholesterol los ntawm cov zis
Ib kauj ruam tseem ceeb hauv kev tsim cov kua tsib yog kev tsim cov kua tsib acids. Cov kua tsib acids yog tsim los ntawm cov roj cholesterol los ntawm ntau yam kev hloov pauv enzymatic hauv hepatocytes. Ib qho enzyme tseem ceeb hauv txoj kev no yog cholesterol 7α-hydroxylase (CYP7A1), uas tswj cov kua tsib acid ntau npaum li cas.
Cov kua qaub uas tsim tshiab tuaj yeem sib xyaw (ua ke) nrog cov amino acids xws li glycine lossis taurine. Cov txheej txheem sib xyaw no ua rau cov kua qaub uas yaj tau hauv dej ntau dua thiab ua haujlwm tau zoo dua hauv kev pab zom cov rog. Tom qab sib xyaw, cov kua qaub uas tshwm sim feem ntau hu ua cov ntsev kua qaub.
2. Kev tso tawm cov khoom ntawm cov kua tsib rau hauv cov kua tsib canaliculi
Thaum cov khoom xyaw ntawm cov kua tsib tau tsim, cov hepatocytes tso lawv tawm mus rau hauv cov kwj dej me me hu ua bile canaliculi. Cov canaliculi no yog cov "gutters" me me nyob nruab nrab ntawm cov hepatocytes. Qhov no yog qhov uas cov kua tsib pib ntws.
Kev ntws ntawm cov kua tsib yuav tsum tau muaj kev ua haujlwm ntawm ntau yam transporters (cov protein hloov pauv) ntawm daim nyias nyias ntawm lub hlwb hepatocyte. Cov ntsev ntawm cov kua tsib, cov bilirubin sib xyaw, phospholipids, thiab lwm yam khoom raug thawb mus rau hauv cov canaliculi. Kev txav ntawm cov khoom no ua rau osmotically nyiam dej thiab electrolytes, ua rau cov kua tsib ntau ntxiv thiab ua rau nws tsis txaus rau kev ntws.
3. Kev hloov kho cov kua tsib los ntawm cov hlwb ntawm cov kua tsib
Cov kua tsib uas cov hepatocytes tsim tawm thawj zaug hu ua cov kua tsib thawj zaug. Thaum nws hla dhau cov kav dej hauv lub siab (cov kav dej hauv lub siab), cholangiocytes tuaj yeem ntxiv bicarbonate (HCO₃⁻) thiab dej. Kev ntxiv bicarbonate pab tshem tawm cov kua qaub hauv plab thaum cov khoom hauv plab nkag mus rau hauv txoj hnyuv me, ua rau ib puag ncig ntawm txoj hnyuv zoo dua rau kev ua haujlwm ntawm cov enzyme zom zaub mov.
Txoj cai no yog cuam tshuam los ntawm cov tshuaj hormones xws li secretin, uas ua rau cov ducts ntawm cov kua tsib tsim cov kua dej uas muaj bicarbonate ntau.
4. Kev khaws cia thiab kev sib sau ua ke hauv lub zais zis
Txawm hais tias cov kua tsib raug tsim tawm tas li, nws tsis tas li ntws ncaj qha mus rau hauv txoj hnyuv. Thaum tsis muaj zaub mov, tshwj xeeb tshaj yog cov khoom noj uas muaj roj ntau, cov kua tsib feem ntau raug xa mus rau lub zais zis kom khaws cia. Hauv lub zais zis, cov kua tsib raug sib sau ua ke: dej thiab qee cov electrolytes raug nqus rov qab, ua rau cov kua tsib tuab dua thiab muaj zog dua thaum xav tau.
5. Tso cov kua tsib rau hauv txoj hnyuv me thaum noj mov
Thaum koj noj mov, tshwj xeeb tshaj yog cov khoom noj uas muaj roj, koj txoj hnyuv me me tso tawm cov tshuaj hormone cholecystokinin (CCK). Cov tshuaj hormone no ua rau lub zais zis nruj thiab tso cov kua tsib mus rau hauv cov hlab ntsha tseem ceeb, uas tom qab ntawd nkag mus rau hauv duodenum (thawj feem ntawm txoj hnyuv me). Tib lub sijhawm, CCK kuj pab so lub sphincter ntawm Oddi, lub "valve" uas tswj cov dej ntws ntawm cov kua tsib thiab cov kua txiv pancreatic mus rau hauv txoj hnyuv.
Tom qab cov kua tsib nkag mus rau hauv txoj hnyuv me, cov ntsev kua tsib ua lawv lub luag haujlwm: tsim cov micelles, khi cov rog thiab cov vitamins uas yaj hauv roj, tom qab ntawd nqa cov khoom zom zaub mov mus rau saum npoo ntawm txoj hnyuv kom nqus tau.
Lub voj voog Enterohepatic: cov kua tsib yog "rov siv dua"
Qhov txaus nyiam yog tias lub cev tsis tso tag nrho cov ntsev bile tom qab siv. Feem ntau ntawm lawv raug nqus rov qab rau hauv qhov kawg ntawm txoj hnyuv me (ileum) thiab thauj rov qab mus rau lub siab los ntawm cov hlab ntsha portal. Cov txheej txheem no hu ua enterohepatic circulation.
Lub voj voog no ua haujlwm tau zoo heev. Cov ntsev ntawm cov kua tsib tuaj yeem siv dua ntau zaus hauv ib hnub. Lub siab tsuas yog xav tau tsim cov kua qaub tshiab me me los hloov cov uas ploj hauv cov quav. Lub kaw lus rov ua dua tshiab no pab lub cev txuag lub zog thiab tswj cov ntsev ntawm cov kua tsib kom zom tau.
Yog tias cov kua tsib tsim tawm lossis cov kua tsib ntws tsis zoo, yuav ua li cas?
Kev cuam tshuam rau kev tsim lossis ntws ntawm cov kua tsib tuaj yeem ua rau muaj ntau yam teeb meem kev noj qab haus huv, piv txwv li:
- Cholestasis (kev thaiv cov kua tsib ntws): tuaj yeem ua rau muaj bilirubin thiab cov ntsev kua tsib hauv cov ntshav, ua rau khaus tawv nqaij, zis dub, quav daj ntseg, thiab mob daj ntseg.
- Pob zeb hauv lub zais zis: feem ntau tshwm sim thaum cov kua tsib puv nrog cov roj cholesterol ntau dhau lossis muaj qhov tsis sib npaug ntawm cov kua tsib.
Kev nqus roj tsis zoo: qhov tsis muaj cov kua tsib tuaj yeem ua rau cov quav roj (steatorrhea) thiab tsis muaj cov vitamins A, D, E, K.
- Kev puas tsuaj rau daim siab lossis cov hlab ntsha hauv cov kua tsib: xws li kab mob siab, mob cirrhosis, lossis o ntawm cov hlab ntsha hauv cov kua tsib tuaj yeem cuam tshuam rau kev tsim/kev thauj cov kua tsib.
Vim tias cov kua tsib muaj feem cuam tshuam rau kev zom zaub mov thiab kev tshem tawm cov khib nyiab, cov teeb meem ntawm lub cev biliary feem ntau muaj kev cuam tshuam dav dav, tsis yog rau lub plab xwb tab sis kuj rau ntawm daim tawv nqaij, lub zog, thiab kev ua haujlwm ntawm lub cev.
Kev kaw
Kev tsim cov kua tsib los ntawm lub siab yog ib qho txheej txheem sib koom tes zoo heev. Cov hepatocytes ua cov kua tsib los ntawm cov roj cholesterol, tso cov ntsev kua tsib thiab ntau yam khoom sib xyaw rau hauv cov kua tsib canaliculi, thiab tom qab ntawd hloov cov kua tsib raws cov ducts kua tsib ua ntej khaws cia thiab sib sau ua ke hauv lub gallbladder. Thaum noj cov khoom noj uas muaj roj ntau, cov kua tsib raug tso tawm mus rau hauv txoj hnyuv me me kom pab zom cov rog thiab nqus cov vitamins. Tom qab siv, feem ntau ntawm cov ntsev kua tsib raug rov ua dua los ntawm kev ncig enterohepatic.
Kev nkag siab txog seb lub siab tsim cov kua tsib li cas pab peb pom tias lub cev no tsis yog tsuas yog "lub lim tshuaj lom," tab sis yog ib qho tseem ceeb uas tswj kev zom zaub mov thiab kev zom zaub mov. Kev tswj hwm kev noj qab haus huv ntawm lub siab los ntawm kev noj zaub mov kom zoo, kev tawm dag zog, thiab kev kuaj mob thaum muaj teeb meem zom zaub mov lossis cov tsos mob ntawm tus mob daj ntseg yog cov kauj ruam tseem ceeb kom ntseeg tau tias lub biliary ua haujlwm zoo tshaj plaws.
