口腔食道胃功能

口腔食道胃功能口腔食道胃功能第1頁(yè)OutlinesPregastricdigestionMasticationSwallowingSecretionofsalivarySaliva：secretion，compositionandfunctionsNervousregulationofsalivarysecretionGastricdigestionGastricsecretionGastricjuice：source，compositionandfunctionsHClsecretion：cellularmechanismandregulationControlofgastricsecretionduringdigestiveperiodGastricmotilityReceptiverelaxation，toniccontractionandPeristalticcontractionGastricemptying：mechanismandcontrol口腔食道胃功能第2頁(yè)胃前消化咀嚼Mastication(chewing)將大顆粒塊狀食物研磨成小塊，增加唾液淀粉酶作用面積與唾液混合，形成食團(tuán)刺激口腔內(nèi)感受器，參加胃、小腸消化功效調(diào)整

口腔食道胃功能第3頁(yè)P(yáng)regastricdigestion口腔食道胃功能第4頁(yè)P(yáng)regastricdigestion吞咽Deglutition分期及特點(diǎn)U口腔食道胃功能第5頁(yè)P(yáng)regastricdigestion蠕動(dòng)Peristalsis蠕動(dòng)機(jī)械消化功效蠕動(dòng)過(guò)程中平滑肌收縮特征介導(dǎo)蠕動(dòng)主要是內(nèi)在神經(jīng)系統(tǒng)口腔食道胃功能第6頁(yè)P(yáng)regastricdigestion食管下括約肌loweresophagealsphincter(LES)功效未進(jìn)食期間…吞咽時(shí)…口腔食道胃功能第7頁(yè)P(yáng)regastricdigestion吞咽時(shí)介導(dǎo)LES張力下降物質(zhì)：NO和VIP（由迷走神經(jīng)末梢釋放）其它體液原因/NOAch口腔食道胃功能第8頁(yè)返流性食管炎Inhumans,commondisordersinvolvingtheesophagusincludeheartburnandgastroesophagealrefluxdisease(GERD).Inbothcases,thelowersphincterdoesnotcloseproperly,allowingacidfromthestomachtorefluxbackintotheesophagus,causesaburningsensationinthechestorthroat(heartburn)oradditionalsignssuchascoughingorasensationofchoking.口腔食道胃功能第9頁(yè)P(yáng)regastricdigestion唾液腺腮腺下頜下腺舌下腺口腔食道胃功能第10頁(yè)P(yáng)regastricdigestion唾液起源：Secretedfromserousandmucouscellsofsalivaryglands理化特征：A97-99.5%water,低滲hypo-osmotic,pH6-7，containing電解質(zhì)–Na+,K+,Cl–,PO42–,HCO3–唾液淀粉酶蛋白質(zhì)–mucin,lysozyme,defensins,andIgA代謝產(chǎn)物–ureaanduricacid口腔食道胃功能第11頁(yè)P(yáng)regastricdigestion導(dǎo)管上皮細(xì)胞：主動(dòng)吸收Na+，被動(dòng)吸收Cl-，主動(dòng)分泌K+和HCO3-

分泌速率改變對(duì)唾液滲透壓影響分泌速率改變對(duì)唾液pH值影響口腔食道胃功能第12頁(yè)P(yáng)regastricdigestion唾液功效形成能夠吞咽食團(tuán)開始對(duì)淀粉化學(xué)性消化（唾液淀粉酶）殺菌和參加機(jī)體防御作用對(duì)牙齒保護(hù)作用口腔食道胃功能第13頁(yè)P(yáng)regastricdigestion唾液分泌神經(jīng)調(diào)整

主要由副交感神經(jīng)調(diào)整交感神經(jīng)興奮時(shí)也能引發(fā)唾液分泌增加刺激和抑制唾液分泌原因

口腔食道胃功能第14頁(yè)胃內(nèi)消化胃主要消化功效:接納和暫時(shí)貯存胃內(nèi)機(jī)械性和化學(xué)性消化將食糜送入小腸（排空）分泌內(nèi)因子，幫助vitaminB12

在小腸吸收口腔食道胃功能第15頁(yè)Gastricdigestion胃液起源賁門腺：mucous幽門腺：mucous泌酸腺SurfaceEpithelium-insolublemucousNeckCells-solublemucousParietal(oroxyntic)Cells-HCl&IntrinsicFactorChiefCells-pepsinogen

口腔食道胃功能第16頁(yè)Gastricdigestion胃液成份Salt,water,HCl,pepsin,intrinsicfactor,andmucus.（pH1.0-3.5,1.5-2.5L/Day）胃液中HCl有哪些生理功效?

分泌速率改變對(duì)胃液成份影響pHK+--嘔吐引發(fā)低血鉀癥口腔食道胃功能第17頁(yè)TEMofrestingparietalcellfrompigletstomach,showingcanaliculus(C)surroundedbynumeroustubulovesicles(TV)andmitochondria.

Bar=1μmTEMofmaximallystimulatedparietalcell(piglet),showinggreatlyenlargedcanaliculiwithelongatedmicrovilli.

Remainingspacehasdenselypackedmitochondriaandveryfewtubulovesicles.

Bar=1μm口腔食道胃功能第18頁(yè)口腔食道胃功能第19頁(yè)壁細(xì)胞分泌鹽酸機(jī)制細(xì)胞內(nèi)H2O分解為H+和OH-

，OH-

與CO2反應(yīng)生成HCO3-;碳酸酐酶（CA）催化這一過(guò)程HCO3-

在基底膜與Cl-交換.HCO3-

隨即進(jìn)入毛細(xì)血管，造成血液pH輕微升高(餐后堿潮，postprandialalkalinetide）Cl-

和K+從管腔膜上特異通道進(jìn)入胃腔管腔膜上質(zhì)子泵（protonpump，H+-K+ATPase)主動(dòng)將H+

泵出細(xì)胞，同時(shí)交換一個(gè)K+

進(jìn)入細(xì)胞管腔內(nèi)，H+與Cl-生成HCl口腔食道胃功能第20頁(yè)Gastricdigestion質(zhì)子泵抑制劑Protonpumpinhibitors,PPIs抑酸機(jī)制Drugshavebeendevelopedthatnon-competivelybindandinactivatetheATPase,resultinginstronginhibitionofacidsecretion.Omeprazole奧美拉唑isanacid-activatedprodrugthatbindscovalentlytotwocysteinesontheATPase,resultinginitsirreversibleinactivation..Otherinhibitors,includinglansoprazole蘭索拉唑,esomeprazole艾美拉唑,rabeprazole雷貝拉唑andpantoprazole泮托拉唑havesimilarmodesofaction.PPIs口腔食道胃功能第21頁(yè)鹽酸分泌調(diào)整內(nèi)源性刺激物：Ach，組織胺和胃泌素經(jīng)過(guò)壁細(xì)胞上各自受體（M3-R，H2-R和G/CCK-B-R）刺激HCl分泌迷走神經(jīng)末梢：AchG細(xì)胞：胃泌素（血液循環(huán)路徑）ECL細(xì)胞：組織胺（旁分泌路徑）ECL細(xì)胞是主要調(diào)整細(xì)胞，其上分布Ach和胃泌素受體G細(xì)胞釋放胃泌素調(diào)整原因?qū)ξ父]機(jī)械牽張刺激和化學(xué)刺激促進(jìn)G細(xì)胞分泌迷走神經(jīng)興奮末梢釋放GRP激活GRP受體促進(jìn)G細(xì)胞分泌起源于D細(xì)胞生長(zhǎng)抑素激活生長(zhǎng)抑素受體抑制G細(xì)胞分泌迷走神經(jīng)末梢釋放Ach作用于D細(xì)胞上受體抑制其分泌生長(zhǎng)抑素，間接促進(jìn)了G細(xì)胞分泌D細(xì)胞介導(dǎo)壁細(xì)胞HCl分泌負(fù)反饋調(diào)整機(jī)制胃竇內(nèi)H+濃度升高，刺激D細(xì)胞分泌生長(zhǎng)抑素口腔食道胃功能第22頁(yè)阿托品Atropine抑酸機(jī)制：阻斷M受體西米替丁cimetidine抑酸機(jī)制：阻斷H2受體SomeotherH2ReceptorAntagonists：ranitidine,famotidineandnizatidine

口腔食道胃功能第23頁(yè)口腔食道胃功能第24頁(yè)Gastricdigestion胃蛋白酶原和胃蛋白酶

胃蛋白酶原激活HCl胃蛋白酶本身激活pHoptima1.8-3.5AchandHCl刺激主細(xì)胞分泌胃蛋白酶原內(nèi)因子IntrinsicFactor結(jié)合VitaminB12，預(yù)防其被消化和破壞與VB12生成復(fù)合物IF-VitB12

是回腸吸收VB12形式缺乏：惡性貧血perniciousanemia(PA)口腔食道胃功能第25頁(yè)Gastricdigestion粘液-碳酸氫鹽屏障Mucus-bicarbonatebarrier物理屏障：厚(500μ)，凝膠狀化學(xué)屏障：碳酸氫鹽-pH梯度口腔食道胃功能第26頁(yè)GastricdigestionReviewquestionHowdoesthestomachprotectitselffromthegastricHCl?GastricbarrierTightjunctionsbetweentheepithelialcellsControlofHClsecretionTrophiceffectsbyGIhormones口腔食道胃功能第27頁(yè)AcutegastritisGastriculcer口腔食道胃功能第28頁(yè)Gastricdigestion消化期胃液分泌調(diào)整口腔食道胃功能第29頁(yè)Gastricdigestion頭期（神經(jīng)調(diào)整）頭部刺激原因：感覺(jué)器官刺激，高級(jí)中樞參加調(diào)整反射支配壁細(xì)胞迷走神經(jīng)興奮(ACh)支配G細(xì)胞迷走神經(jīng)興奮（GRP）支配ECL迷走細(xì)胞興奮（GRP）支配D細(xì)胞迷走神經(jīng)興奮（Ach）口腔食道胃功能第30頁(yè)Gastricdigestion胃期GastricPhase胃內(nèi)機(jī)械和化學(xué)刺激經(jīng)短反射和長(zhǎng)反射（迷走-迷走反射）作用于Parietalcells(ACh)Gcells(releasegastrin)ECLcells(releasehistamine)胃酸分泌正反饋機(jī)制口腔食道胃功能第31頁(yè)Gastricdigestion腸期(pHabove3)

蛋白質(zhì)消化產(chǎn)物（多肽）在十二指腸刺激G細(xì)胞食糜進(jìn)入十二指腸機(jī)械刺激G細(xì)胞腸泌酸素enterooxyntin作用口腔食道胃功能第32頁(yè)Gastricdigestion抑制胃酸分泌原因：胃內(nèi)：GastricpH<2--->gastricDcellsreleasesomatostatinwhichinhibitsgastrinrelease十二指腸：Acidinduodenum--->secretin&CCK--->inhibitsgastricsecretionandmotilityAcid,fats,hyper-osmoticsolutionsintheduodenum--->releaseofenterogastrones--->inhibitgastricmotilityandsecretionGastricInhibitoryPeptide(GIP)fromduodenum--->inhibitsparietalcellfunction

Distensionandchemicalstimulation

--->

腸胃反射Entero-gastricreflex

口腔食道胃功能第33頁(yè)Gastricdigestion胃運(yùn)動(dòng)胃生理功效分區(qū)

Emptying口腔食道胃功能第34頁(yè)Gastricdigestion擔(dān)心性收縮頭端胃（近端胃）容受性舒張神經(jīng)反射，NO和VIP介導(dǎo)VagusNO,VIP[Entericnervoussystem]口腔食道胃功能第35頁(yè)口腔食道胃功能第36頁(yè)Gastricdigestion遠(yuǎn)端胃蠕動(dòng)Peristalticcontraction起源于胃中部（3次/min）向幽門方向推進(jìn)，一波未平一波又起，蠕動(dòng)波得以疊加、增強(qiáng)幽門附件蠕動(dòng)波最強(qiáng)食糜數(shù)毫升被擠入十二指腸大個(gè)別返回胃竇深入研磨和混合

口腔食道胃功能第37頁(yè)Gastricdigestion胃排空概念促進(jìn)胃排空原因（反之，抑制）IntenseperistalticcontractionsDecreasedpylorictoneRelativelydecreasedduodenalmotility胃排空速率由胃內(nèi)原因和十二指腸內(nèi)原因共同調(diào)整GastricfactorspromoteemptyingDuodenalfactorsinhibitstomachemptying口腔食道胃功能第38頁(yè)Gastricdigestion神經(jīng)和體液原因均參加胃排空速率調(diào)整維持適當(dāng)胃排空速率生理意義？？口腔食道胃功能第39頁(yè)GastricdigestionMigratingmotorcomplexes(MMC)移行性復(fù)合運(yùn)動(dòng)arewavesofactivitywhichsweepthroughtheintestinesinaregularcycleduringfastingstate(originatesinthestomachroughlyevery75-120minu