消化與吸收DigestionandAbsorption-浙江大學(xué)課件

消化與吸收

DigestionandAbsorption夏強(qiáng)，PhD浙江大學(xué)醫(yī)學(xué)院生理學(xué)系電話：88206417,88208252Email：xiaqiang@兩個(gè)概念消化——是指食物中所含的營養(yǎng)物質(zhì)在消化道內(nèi)被分解為可吸收的小分子物質(zhì)的過程機(jī)械性消化化學(xué)性消化吸收——食物經(jīng)消化后形成的小分子物質(zhì)，以及維生素、無機(jī)鹽和水通過消化道黏膜上皮細(xì)胞進(jìn)入血液和淋巴的過程消化系統(tǒng)消化道消化腺消化系統(tǒng)的功能運(yùn)動(dòng)Movement分泌Secretion消化Digestion吸收Absorption排出EliminationStructureofthealimentarycanalNormalBERfrequenciesinthegastrointestinalsystem基本電節(jié)律basicelectricalrhythm:BER兩套神經(jīng)系統(tǒng)腸（內(nèi)在）神經(jīng)系統(tǒng)Entericnervoussystem(intrinsic)自主（外來）神經(jīng)系統(tǒng)Autonomicnervoussystem(extrinsic)胃腸激素

Gastrointestinalhormones消化道內(nèi)所含的內(nèi)分泌細(xì)胞數(shù)遠(yuǎn)大于體內(nèi)所有內(nèi)分泌腺所含的細(xì)胞總數(shù)消化道是目前所知的體內(nèi)最大的內(nèi)分泌器官Gastrointestinalhormones，Guthormones口腔內(nèi)消化咀嚼和吞咽

MasticationandswallowingTheswallowingreflexiscoordinatedbythemedullaoblongata,whichstimulatestheappropriatesequenceofcontractionandrelaxationintheparticipatingskeletalmuscle,sphincters,andsmoothmusclegroups.Thecoordinatedsequenceofcontractionandrelaxationintheupperesophagealsphincter,theesophagus,andtheloweresophagealsphincterisnecessarytodeliverswallowedfoodtothestomach.胃內(nèi)消化胃的主要功能：暫時(shí)儲(chǔ)存食物消化食物少量吸收胃液Gastricjuice成分HCl胃蛋白酶原Pepsinogen黏液Mucus碳酸氫鹽HCO3-內(nèi)因子IntrinsicfactorpH0.9-1.5黏液-碳酸氫鹽屏障Mucus-HCO3-barrier幽門螺旋桿菌(HelicobacterPylori)胰液分泌

Pancreaticsecretion胰液pH7.8~8.4~1500ml/dayIsosmoticComponents:Pancreaticdigestiveenzymes:secretedbypancreaticaciniSodiumbicarbonate:secretedbysmallductulesandlargerductsSecretionofpancreaticdigestiveenzymesCarbohydrates--PancreaticamylasePancreaticlipaseFatCholesterolesterasePhospholipaseTrypsinogenProteinsChymotrypsinogenProcarboxypolypeptidaseProelastase急性胰腺炎

Acutepancreatitis膽汁分泌

Secretionofbilebytheliver膽汁的成分HCO3-

BilesaltsPhospholipidsCholesterolBilepigments…膽汁的功能：EmulsifyingordetergentfunctionofbilesaltsBilesaltshelpintheabsorptionof:FattyacidMonoglyceridesCholesterolOtherlipidsBigDropletsofFatSmallDropletsofFatMicellesFattyAcidsandMonoglyceridesChylomicronAssemblyDistributionandProcessingPreventingthecholesterolprecipitation&gallstones大腸的功能吸收水分和無機(jī)鹽吸收微生物合成的維生素B復(fù)合物和維生素K完成對(duì)食物殘?jiān)募庸?，形成并暫時(shí)儲(chǔ)存糞便Inthelargeintestine,activetransportofsodium,coupledwithosmoticabsorptionofwater,aretheprimaryactivities.

MicrobeshereareactiveintheproductionofvitaminK.排便反射Defecationreflex體溫

BodyTemperature體溫恒溫動(dòng)物保持正常的體溫是機(jī)體進(jìn)行新陳代謝和生命活動(dòng)的必要條件核心溫度Coretemperature表層溫度ShelltemperatureNormalcoretemperatureSiteMeanvalueoftemperatureStandarddeviationRangeofvariationoftemperatureAxillary36.79oC0.35736.0-37.4oCOral37.19oC0.24936.7-37.7oCRectal37.47oC0.25136.9-37.9oCThecircadian(“aboutaday”)rhythmofbodytemperaturepersistsevenamongpatientsinacoma;inadditiontothisbasicrhythm,fevers,exercise,andotheractivitiescanalterthebodytemperature.Bodytemperatureisacontrolledvariablethatissubjecttohomeostaticregulation.Thiscartoonindicatessomeofthewaysthatenvironmentalfactorscanincreaseordecreasebodytemperature.體溫調(diào)節(jié)

自主性體溫調(diào)節(jié)Autonomicthermoregulation行為性體溫調(diào)節(jié)Behavioralthermoregulation體溫中樞——主要在下丘腦Hypothalamus腎臟生理學(xué)

RenalPhysiology腎臟的功能調(diào)節(jié)水和電解質(zhì)平衡，調(diào)節(jié)體液滲透壓調(diào)節(jié)酸堿平衡排出機(jī)體代謝終產(chǎn)物及進(jìn)入體內(nèi)的過剩物質(zhì)和異物糖異生內(nèi)分泌：促紅細(xì)胞生成素（erythropoeitin）腎素（renin）1,25-二羥膽骨化醇（1,25-OH2-D3）其他：激肽，前列腺素（PGE2,PGI2）尿生成的三個(gè)基本過程濾過Filtration重吸收Reabsorption分泌SecretionSubstanceXisfilteredandsecretedbutnotreabsorbed.SubstanceYisfilteredandsomeofitisreabsorbed.SubstanceZisfilteredandcompletelyreabsorbed.CompositionintheFiltrationFluidStructureoftheFiltrationMembrane葡萄糖的重吸收正常情況下，全部重吸收小管葡萄糖最大轉(zhuǎn)運(yùn)率Tm-G:Tubulartransportmaximumforglucose腎糖閾RenalthresholdforglucoseCriticalvalueoftheplasmaglucoseconcentrationwhenthekidneybeginstoexcreteglucose160-180mg/dL尿量正常：1000-2000ml/24hr多尿Polyuria：>2500ml/24hr少尿Oliguria：<400ml/24hr，或<17ml/hr無尿Anuria：<100ml/24hr，或12hr完全無尿抗利尿激素

Antidiuretichormone(ADH)又稱血管升壓素Vasopressin下丘腦合成垂體后葉釋放作用：促進(jìn)遠(yuǎn)曲小管和集合管對(duì)水的通透性收縮血管Actionofantidiuretichormoneonaquaporin(AQP)transport.AC,adenylatecyclase;AP1,transcriptionfactor;AVP,argininevasopressin;cAMP,cyclicadenosinemonophosphate;CRE,cAMPresponseelement;CREB-P,CREbindingprotein;EP3,prostaglandinreceptor;PGE2,prostaglandinE2.(FromBrownD,NielsenS:Thecellbiologyofvasopressinaction.InBrennerBM[ed]:BrennerandRector‘sTheKidney,7thed.Philadelphia,WBSaunders,2004,p574.)水利尿Waterdiuresis尿崩癥DiabetesinsipidusInakidney-failurepatientundergoingdialysis,thebloodisbrieflyremovedfromthebod