Ntau xyoo dhau los, ntau cov ntaub ntawv tshiab txog cov kua tsib thiab nws cov kua qaub tau txais. Hauv qhov no, nws tau dhau los ua qhov tsim nyog los kho thiab nthuav tawm tswv yim txog lawv qhov tseem ceeb rau lub neej ntawm tib neeg lub cev.
Lub luag haujlwm ntawm cov kua tsib acids. Cov ntaub ntawv dav dav
Kev txhim kho sai thiab txhim kho ntawm txoj kev tshawb fawb tau ua rau nws tuaj yeem kawm cov kua tsib kom ntxaws ntxiv. Piv txwv li, tam sim no muaj kev nkag siab zoo dua ntawm cov metabolism, lawv cov kev cuam tshuam nrog cov proteins, lipids, pigments thiab lawv cov ntsiab lus hauv cov ntaub so ntswg thiab kua dej. Cov ntaub ntawv pov thawj qhia tau tias cov kua tsib acids tseem ceeb heev tsis yog rau kev ua haujlwm ntawm lub plab zom mov xwb. Cov tebchaw no koom nrog ntau cov txheej txheem hauv lub cev. Nws tseem yog ib qho tseem ceeb uas, ua tsaug rau kev siv cov kev tshawb fawb tshiab tshaj plaws, nws muaj peev xwm txiav txim siab ntau npaum li cas cov kua tsib acids coj tus cwj pwm hauv cov ntshav, nrog rau qhov lawv cuam tshuam li cas rau cov kab mob ua pa. Ntawm lwm yam, cov tebchaw cuam tshuam rau qee qhov chaw ntawm lub paj hlwb. Lawv qhov tseem ceeb hauv intracellular thiab sab nraudcov txheej txheem membrane. Qhov no yog vim cov kua tsib acids ua raws li surfactants nyob rau hauv ib puag ncig ntawm lub cev.
Historical facts
Hom tshuaj lom neeg no tau tshawb pom los ntawm tus kws tshawb fawb Strecker nyob rau nruab nrab xyoo pua 19th. Nws tswj xyuas kom pom tias cov kua tsib ntawm nyuj muaj ob cov organic acids. Thawj qhov muaj cov sulfur. Qhov thib ob kuj muaj cov tshuaj no, tab sis muaj cov mis sib txawv kiag li. Nyob rau hauv tus txheej txheem ntawm splitting cov tshuaj sib txuas, cholic acid yog tsim. Raws li qhov tshwm sim ntawm kev hloov pauv ntawm thawj qhov sib xyaw uas tau hais los saum no, glycerol yog tsim. Nyob rau tib lub sijhawm, lwm cov kua tsib acid tsim cov khoom sib txawv kiag li. Nws hu ua taurine. Yog li ntawd, thawj ob lub tebchaw tau muab cov npe nrog tib lub npe raws li cov khoom tsim tawm. Qhov no yog li cas tauro- thiab glycocholic acid tshwm sim, feem. Qhov kev tshawb pom ntawm tus kws tshawb fawb no tau muab lub zog tshiab rau kev kawm ntawm chav kawm ntawm cov tshuaj lom neeg no.
Bile acid sequestrants
Cov tshuaj no yog ib pawg ntawm cov tshuaj uas muaj lipid-txo cov nyhuv ntawm tib neeg lub cev. Nyob rau hauv xyoo tas los no, lawv tau nquag siv los txo cov roj cholesterol. Qhov no tau txo qis kev pheej hmoo ntawm ntau yam kab mob plawv thiab kab mob coronary. Tam sim no, lwm pab pawg ntawm cov tshuaj zoo dua yog siv dav hauv cov tshuaj niaj hnub. Cov tshuaj lipid-txo cov tshuaj no yog statins. Lawv siv ntau zaus vim muaj kev phiv tsawg.kev ua. Tam sim no, cov kua tsib kua qaub sequestrants tau siv tsawg thiab tsawg. Qee zaum lawv tsuas yog siv los ua ib feem ntawm txoj kev kho mob thiab txhawb nqa.
Ntaus
Cov chav kawm steroid suav nrog monocarbaic hydroxy acids. Lawv yog cov active solids uas tsis zoo soluble nyob rau hauv dej. Cov kua qaub no tshwm sim los ntawm kev ua cov roj cholesterol los ntawm lub siab. Hauv cov tsiaj nyeg, lawv muaj 24 carbon atoms. Cov muaj pes tsawg leeg ntawm cov kua tsib lub tebchaw nyob rau hauv ntau hom tsiaj yog txawv. Cov hom no tsim taucholic thiab glycolic acids hauv lub cev. Chenodeoxycholic thiab cholic tebchaw yog nyob rau hauv chav kawm ntawm cov ntsiab lus tseem ceeb. Lawv tsim li cas? Hauv cov txheej txheem no, daim siab biochemistry tseem ceeb. Cov ntsiab lus tseem ceeb tshwm sim los ntawm kev sib txuas ntawm cov cholesterol. Tom qab ntawd, cov txheej txheem conjugation tshwm sim ua ke nrog taurine lossis glycine. Cov kua qaub no tom qab ntawd tso rau hauv cov kua tsib. Cov tshuaj lithocholic thiab deoxycholic yog ib feem ntawm cov tebchaw thib ob. Lawv raug tsim nyob rau hauv cov hnyuv loj los ntawm thawj cov kua qaub nyob rau hauv lub zog ntawm cov kab mob hauv zos. Tus nqi ntawm kev nqus ntawm deoxycholic compounds yog ntau dua li ntawm lithocholic compounds. Lwm cov kua tsib acids tshwm sim nyob rau hauv me me heev. Piv txwv li, ursodeoxycholic acid yog ib qho ntawm lawv. Yog tias mob cholestasis tshwm sim, cov tshuaj no muaj nyob rau hauv ntau. Qhov piv txwv ntawm cov tshuaj no yog 3: 1. Thaum nrog cholestasis, cov ntsiab lus ntawm cov kua tsib acids yog ntau tshaj. Micelles yog aggregatelos ntawm lawv cov molecules. Lawv raug tsim tsuas yog thaum cov concentration ntawm cov tebchaw nyob rau hauv ib tug aqueous tov tshaj lub cim txwv. Qhov no yog vim cov kua tsib acids yog surfactants.
Ntawm cov roj cholesterol
Cov khoom no tsis zoo soluble hauv dej. Tus nqi ntawm solubility ntawm cov cholesterol hauv cov kua tsib nyob ntawm qhov sib piv ntawm lipid concentration, nrog rau cov molar concentration ntawm lecithin thiab acids. Mixed micelles tshwm sim tsuas yog thaum qhov kev faib ua feem ntawm tag nrho cov ntsiab lus no raug tswj xyuas. Lawv muaj cov cholesterol. Cov nag lossis daus ntawm nws cov muaju yog nqa tawm nyob rau hauv cov xwm txheej ntawm kev ua txhaum ntawm qhov piv no. Lub luag haujlwm ntawm cov kua tsib acids tsis txwv rau kev tshem tawm cov cholesterol los ntawm lub cev. Lawv txhawb kev nqus cov rog hauv cov hnyuv. Micelles kuj raug tsim thaum lub sijhawm txheej txheem no.
Txoj kev sib txuas
Ib qho ntawm cov xwm txheej tseem ceeb rau kev tsim cov kua tsib yog lub zog ntawm cov kua qaub. Cov tebchaw no ua lub luag haujlwm tseem ceeb hauv kev thauj cov electrolytes thiab dej hauv cov hnyuv me thiab loj. Lawv yog cov hmoov tawv tawv. Lawv melting point yog heev. Lawv muaj ib tug iab saj. Bile acids tsis zoo soluble hauv dej, thaum lawv zoo nyob rau hauv alkaline thiab cawv daws. Cov tshuaj no yog derivatives ntawm cholanic acid. Tag nrho cov kua qaub no tshwm sim tshwj xeeb hauv cov roj cholesterol hepatocytes.
Influence
Cov ntsev yog qhov tseem ceeb tshaj plaws ntawm tag nrho cov acidic compounds. Qhov no yogvim muaj ntau yam khoom ntawm cov khoom no. Piv txwv li, lawv muaj ntau dua polar tshaj cov kua tsib dawb ntsev, muaj ib qho me me micelle concentration txwv, thiab secreted sai dua. Lub siab yog tib lub cev muaj peev xwm hloov cov roj (cholesterol) mus rau hauv cov cholanic acids tshwj xeeb. Qhov no yog vim lub fact tias cov enzymes uas koom nyob rau hauv conjugation muaj nyob rau hauv hepatocytes. Cov kev hloov hauv lawv cov dej num yog ncaj qha nyob ntawm seb muaj pes tsawg leeg thiab tus nqi ntawm cov kua tsib acids ntawm daim siab. Cov txheej txheem synthesis yog tswj los ntawm kev tawm tswv yim tsis zoo. Qhov no txhais tau hais tias qhov kev siv ntawm qhov tshwm sim no yog nyob rau hauv kev sib raug zoo nrog cov tam sim no ntawm cov kua tsib acids nyob rau hauv lub siab. Tus nqi ntawm lawv cov synthesis nyob rau hauv tib neeg lub cev yog heev tsawg - los ntawm ob puas mus rau peb puas milligrams ib hnub twg.
Main Tasks
Bile acids muaj ntau yam kev siv. Nyob rau hauv tib neeg lub cev, lawv tsuas yog nqa tawm cov synthesis ntawm cov roj (cholesterol) thiab cuam tshuam rau kev nqus cov rog ntawm cov hnyuv. Tsis tas li ntawd, cov tshuaj sib xyaw ua ke tau koom nrog hauv kev tswj cov kua tsib kua tsib thiab tsim cov kua tsib. Cov tshuaj no kuj muaj kev cuam tshuam rau cov txheej txheem ntawm kev zom thiab nqus cov lipids. Lawv cov tebchaw yog sau rau hauv cov hnyuv me. Cov txheej txheem tshwm sim nyob rau hauv kev cuam tshuam ntawm monoglycerides thiab dawb fatty acids, uas yog nyob rau saum npoo ntawm fatty deposits. Nyob rau hauv cov ntaub ntawv no, ib tug nyias zaj duab xis yog tsim, uas tiv thaiv kev sib txuas ntawm me me tee roj rau hauv cov loj. Yog li ntawd, qhov nro saum npoo yog txo qis heev. Qhov no ua rautsim cov tshuaj micellar. Lawv, nyob rau hauv lem, pab txhawb kev txiav txim ntawm pancreatic lipase. Nrog kev pab los ntawm cov tshuaj tiv thaiv fatty, nws zom lawv mus rau hauv glycerol, uas yog absorbed los ntawm txoj hnyuv phab ntsa. Cov kua tsib ua ke nrog fatty acids uas tsis yaj hauv dej thiab tsim choleic acids. Cov tebchaw no nkag tau yooj yim cleaved thiab sai sai absorbed los ntawm lub villi ntawm sab sauv plab hnyuv. Choleic acids hloov mus rau hauv micelles. Tom qab ntawd lawv tau nqus mus rau hauv cov hlwb, thaum yooj yim kov yeej lawv daim nyias nyias.
Cov ntaub ntawv tshawb fawb tshiab hauv cheeb tsam no tau txais. Lawv ua pov thawj tias kev sib raug zoo ntawm cov roj ntsha thiab cov kua tsib acids hauv lub cell tawg. Cov qub yog qhov kawg tshwm sim ntawm lipid absorption. Qhov kawg - los ntawm cov hlab ntsha portal nkag mus rau lub siab thiab cov ntshav.
