Cov rog uas nkag mus rau hauv lub cev los ntawm sab nraud yog qhov tseem ceeb heev rau kev tswj nws cov qauv tsim nyog thiab ua haujlwm zoo. Kev zom thiab nqus tau tshwm sim hauv duodenum. Nws yog nyob ntawd uas cov dej-soluble lipolytic enzymes ntsib nrog cov lipids lawv tus kheej. Tab sis rau kev sib cuam tshuam ntawm fatty thiab aqueous theem, intermediaries yog xav tau - emulsifiers. Thiab rog emulsification yog cov txheej txheem ntawm kev sib tov ob theem thiab dispersing loj cov roj tee rau hauv microscopic sawv daws yuav.
Ib tug neeg noj li 80-100 grams roj ib hnub twg, muaj cov roj cholesterol esters, triacylglycerols thiab phospholipids. Ntawm no, kwv yees li 70% yog tsiaj rog thiab 30% yog zaub. Qhov chaw ntawm cov rog muaj ntau heev - cov no yog cov roj, txiv hmab txiv ntoo thiab zaub, txiv ntseej.
Kev sib xyaw ntawm cov rog, zoo li lwm yam khoom hauv peb lub cev, yog txheej txheem nyuaj thiab ntau theem. Rau nws ib txwm ua haujlwm nws yog qhov tsim nyogKev koom tes ntawm tag nrho cov plab hnyuv siab raum, daim siab nrog lub gallbladder, txiav txiav, cov tshuaj hormones thiab enzymes, nrog rau lwm yam khoom muaj nyob hauv cov zaub mov. Thiab txhawm rau kom cov rog ua emulsified hauv cov hnyuv, cov zaub mov yuav tsum tig mus rau hauv chyme thiab mus dhau ib ntus.
qhov ncauj kab noj hniav
khoom noj khoom haus yog ua los ntawm qaub ncaug, zom thiab ua tau raws li thawj enzymes. Chyme yog tsim, ib pob khoom noj. Ib puag ncig hauv qhov ncauj kab noj hniav yog alkaline. Hauv seem no ntawm txoj hnyuv, kev tawg ntawm cov carbohydrates yooj yim (monosaccharides) pib nquag.
Thiab txawm hais tias muaj cov qog nyob rau sab nraub qaum ntawm tus nplaig uas tso tawm lipase, lipid digestion hauv cov neeg laus yeej tsis pom ntawm no. Qhov no yog vim nws qhov me me. Yog li, cov enzyme tsuas yog sib xyaw nrog chyme thiab dhau los ntawm txoj hlab pas mus rau lub plab.
Lipolysis hauv menyuam yaus
Hauv cov menyuam mos, tus nplaig lipase ntau dua. Nws pib sawv tawm thaum tus menyuam nqus lub mis. Txog li ib xyoos, nws yog qhov lipase uas ua lub luag haujlwm tseem ceeb hauv kev zom cov mis nyuj rog. Thaum lub hnub nyoog no, lub ncov ntawm nws cov dej num tshwm sim ntawm pH 4-4, 5, raws li, nyob rau hauv lub plab rau qhov zoo tagnrho tej yam kev mob. Mis nws tus kheej yog ib qho kev daws teeb meem emulsified, piv txwv li dej thiab cov roj me me sib xyaw hauv nws. Yog li ntawd, cov emulsification ntawm cov rog nyob rau hauv cov me nyuam nquag pib nrog lub qhov ncauj kab noj hniav thiab mus txuas ntxiv nyob rau hauv lub plab, uas ho accelerates lub nqus ntawm cov mis nyuj.
plab
Hauv lub plab ntawm tus neeg laus, ib puag ncig acidic feem ntau yog pH 1-1.5. Qhov kev ua ntawm tus nplaig lipase yuav tsum muaj pH ntawm 5.5-7.5. Yog li ntawd, cov enzyme uas yog ib feem ntawm lub chyme yog inactive thiab nws lub luag hauj lwm nyob rau hauv lipid digestion yog heev insignificant. Hauv lub plab, cov zaub mov raug cuam tshuam rau kev ua ntawm cov kua qaub, thiab kev zom zaub mov ntawm cov protein thiab carbohydrates pib ntawm no. Tab sis txij li thaum emulsification ntawm cov rog tshwm sim nyob rau hauv qhov kev txiav txim ntawm cov kua tsib, nws yog cov lipids uas dhau yuav luag tsis hloov, tsis-emulsified rau hauv qis seem ntawm lub plab hnyuv ib ntsuj av. Txawm li cas los xij, cov roj me me uas tau nqus ntawm theem no yog hloov mus rau cov roj fatty acids dawb. Thiab lawv, nyob rau hauv lem, nkag mus rau hauv cov hnyuv thiab pab txhawb emulsification, npaj chyme lipids rau kev txiav txim ntawm pancreatic lipase.
Lub duodenum
Ua ntej, thaum chyme nkag mus rau hauv duodenum, ob lub tshuaj hormones raug tso tawm - secretin thiab cholecystokinin. Nyob rau hauv qhov kev txiav txim ntawm thawj zaug ntawm lub txiav, bicarbonate ions nquag pib ntws. Lawv neutralize lub plab hydrochloric acid uas tuaj nrog chyme. Nyob rau tib lub sijhawm, cov pa roj carbon dioxide tso tawm ua rau lub softening thiab sib tov ntawm cov zaub mov bolus. Tom ntej no, cov txheej txheem alkaline zaub mov bolus yog npaj rau kev tawg rog.
Hauv plab hnyuv lumen ib txwm muaj kua txiv pancreatic nrog lipases, kua txiv plab. Tom qab noj cov zaub mov muaj roj, lub gallbladder cog lus nyob rau hauv qhov kev txiav txim ntawm cholecystokinin thiab cov kua tsib tso rau hauv lub lumen ntawm duodenum. Nws muaj ntau cov kua tsib acids, roj cholesterol thiab phospholipids.
Yog li hais tau nyab xeebtias emulsification ntawm cov rog tshwm sim nyob rau hauv qhov kev txiav txim ntawm tag nrho cov complex ntawm active tshuaj. Tab sis vim qhov tseeb tias pancreatic lipases yog hydrophilic thiab cov rog yog hydrophobic, tsis muaj cov txheej txheem emulsification, cov tshuaj tiv thaiv ntawm lawv tsuas yog tshwm sim ntawm qhov sib cuam tshuam, thiab qhov no yog qhov me me heev. Emulsification ntawm cov rog lov cov roj loj loj rau hauv cov me me, cov theem cuam tshuam, feem, nce ntau zaus. Active digestion los ntawm lipolytic enzymes ua tau. Xav txog cov txheej txheem kom ntxaws ntxiv.
Emulsification ntawm cov rog nrog cov kua tsib
Bile yog tsim los ntawm hepatocytes ntawm daim siab thiab nkag mus rau lub gallbladder. Nyob rau hauv nws, nws accumulates kom txog thaum tau txais cov khoom noj muaj roj nyob hauv plab. Tom qab ntawd, nws cog lus thiab cov kua tsib ntws mus rau hauv duodenum.
Bile acids yog qhov tseem ceeb rau emulsifying rog. Lawv tsim nyob rau hauv daim siab hlwb, hepatocytes, thiab los ntawm qhov ntawd lawv nkag mus rau hauv lub gallbladder. Nyob ntawd lawv muaj nyob rau hauv muaj pes tsawg leeg ntawm khub ntsev - glycocholeate thiab taurocholeate.
Muaj ntau ntau yam ntawm cov kua tsib, tab sis lawv txhua tus muaj ob yam (paired bile acids): kua tsib kua qaub thiab glycine - 70% (glycocholic, glycodeoxycholic thiab glycochenodeoxycholic acids) los yog taurine - 30% (taurocholic, taurodeoxycholic, taurochenodeoxycholic acid).
Micelle formation
Raws li, thaum lub sijhawm peristalsis hauv duodenum, emulsification ntawm cov rog tshwm sim, qhov twgCov khoom tsim nyog rau nws yog sib xyaw: cov molecules ntawm triacylglycerols thiab cov roj cholesterol esters yog hydrophilic thiab sib nyiam. Phospholipids yog attracted rau lawv nrog lawv hydrophilic ib feem - ib tug core yog tsim. Nrog lawv cov hydrophobic ib feem, phospholipids diverge mus rau sab, yog li ua rau sab nrauv. Qhov no yog qhov emulsified me me poob roj zoo li, uas yog, micelle. Lub particle txoj kab uas hla yog hais txog 0.5 µm. Hydrophobic bile acids lo rau sab nrauv ntawm cov micelles, lawv zoo li tsim ib zaj duab xis rau ntawm cov npuas, uas tiv thaiv lawv los ntawm kev ua ke.
Tsis tas li ntawd, cov kua tsib ntsev ntawm qhov cuam tshuam txo qhov nro ntawm qhov chaw, uas ua rau cov roj emulsion ua kom ruaj khov. Uas yog, qhov tseeb, lawv ua raws li ib tug natural stabilizer nyob rau hauv lub cev. Tom qab ntawd, tag nrho cov xwm txheej raug tsim rau kev zom ntxiv ntawm lipids nrog kev pab ntawm pancreatic enzymes.
Qhov no los yog zoo sib xws emulsification ntawm cov rog tshwm sim nyob rau hauv lub cev ntawm tag nrho cov tsiaj, thiab nws yog tshwj xeeb tshaj yog muaj feem xyuam rau cov neeg uas noj tsiaj rog, vim hais tias lawv nqus tau qeeb qeeb vim lub complex qauv ntawm lub molecules.
plab hnyuv loj
Tom qab tsim cov tshuaj sib cais zoo nrog cov micelles thawj, lawv cov txheej txheem nrog pancreatic enzymes pib. Ntawm pH 8, 0, hydrolysis cov tshuaj tiv thaiv ntawm ester bonds tshwm sim hauv triacylglyceride molecules. Raws li qhov tshwm sim ntawm cov tshuaj tiv thaiv, los ntawm txhua molecule ntawm triacylglyceride, ob molecules ntawm fatty acids thiab ib tug molecule ntawm beta-monoglycerides. Ib qho me me ntawm glycerol molecules kuj tsim. Tom qab ntawd, twb sib xyaw micelles nkag mus rau hauv plab hnyuv epithelium. Hauv epitheliocytes, cov tshuaj tiv thaiv ntawm resynthesis ntawm cov tshuaj no tshwm sim. Ib feem ntawm cov micelles nyob rau hauv daim ntawv tsis hloov mus rau hauv tib neeg lymphatic system. Cov so hauv daim ntawv ntawm chylomicrons thiab high-density lipoproteins raug xa mus rau kev ncig. Cov no yog cov qauv thauj khoom tseem ceeb ntawm cov rog hauv tib neeg lub cev. Thiab cov kua tsib acids los ntawm micelles los ntawm cov hlwb ntawm txoj hnyuv villi nkag mus rau hauv cov hlab ntsha portal thiab los ntawm qhov ntawd rov qab mus rau lub siab.
Fat emulsification disorders
Qee lub sij hawm lub cev ua haujlwm zoo ntawm kev nqus rog ua rau tawg. Lawv tuaj yeem nyob ntawm ntau theem ntawm qhov system no. Cov no yog cov teeb meem ntawm lub siab, lub gallbladder, lawv cov ducts thiab cov hnyuv, nrog rau kev ua haujlwm tsis zoo - tsim cov enzymes tsis txaus, piv txwv li.
Muaj peev xwm ua rau tsis muaj roj emulsification:
- txo qis hauv kev tsim cov kua tsib hauv daim siab (ntau kab mob siab - mob hnyav, mob ntev thiab mob siab autoimmune, cirrhosis, kab mob lom);
- ua tsis taus pa ntawm lub gallbladder (dyskinesia thiab akinesia ntawm lub gallbladder);
- thaiv lub zais zis lossis nws cov ducts los ntawm sab hauv (tej zaum muaj kab mob gallstone, qog hauv nws);
- compression ntawm lub gallbladder los yog duct los ntawm sab nraud (tejzaum nyob rau hauv lub xub ntiag ntawm qog los yog nce nyob rau hauv lub cev nyob sib ze).
Tib lub sijhawm, cov kua tsib kua qaub hauv cov kua tsib txo qis lossis tsawg dua ntawm cov tshuaj nkag mus rau hauv txoj hnyuv lumen. Yog li ntawd, tsawg micelles raug tsim, thiab cov tshuaj tiv thaivhydrolysis qeeb dua. Ib feem ntawm cov roj undigested dhau los ntawm cov hnyuv thiab tawm tsis hloov, steatorrhea tshwm sim. Tsis tas li ntawd, qee zaum cov rog pib tawm hauv lub cev tsis yog ib txwm ua, tab sis, piv txwv li, nrog zis (lipuria) lossis feem ntau los ntawm daim tawv nqaij (seborrhea). Cov mob no yog cov tsos mob ntawm cov kab mob.
Malabsorption
Malabsorption syndrome yog suav tias yog qhov teeb meem loj tshaj plaws malabsorption. Nws yog los ntawm hereditary etiology thiab tau txais. Lub ntsiab pathophysiological yam ntxwv yog malabsorption ntawm cov tshuaj nyob rau hauv cov hnyuv. Cov tsos mob: mob plab o, raws plab, steatorrhea, fatty ci quav quav. Nyob rau hauv cov ntaub ntawv hnyav, muaj qhov hnyav poob, beriberi, kev ua txhaum ntawm cov qauv ntawm daim tawv nqaij thiab mucous daim nyias nyias - dryness, o, nkig nkhaus rau tes, plaub hau poob. Lub paj hlwb kuj raug kev txom nyem - vegetovascular dystonia, tsis muaj zog, thiab pw tsaug zog tuaj yeem tshwm sim. Hauv qhov xwm txheej hnyav, cov kua dej pib nkag mus rau hauv lub plab kab noj hniav, tej zaum yuav muaj peripheral edema, paresthesia, tsis pom kev.
Zoo kawg
Cov metabolism hauv rog yog txheej txheem nyuaj heev. Txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau nws nws nws yog ib qho tsim nyog yuav tsum ua kom cov lipase ntau ntxiv ntawm cov enzymes digestive. Nws yog nws uas tso cai rau ib tug neeg kom nqus li 100 grams roj ib hnub twg. Tsis txaus emulsification ua rau muaj kab mob hauv lub xeev, suav nrog kev ua rau muaj kev phom sij rau lub neej.
