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TheDigestiveSystem,TheDigestiveSystem,Gastrointestinaltract胃肠道Accessoryorgans辅助器官,(Para.1),TheorganizationofthegastrointestinaltractWhatarethefourlayers?(Concentriclayers)SublayersIntrinsicnerves(内神经),Thegastrointestinaltract胃肠道,Thesubmucosalplexus(Meissnerplexus)黏膜下层神经丛（即迈斯纳神经丛）Themyentericplexus(Auerbachplexus)肠肌神经丛（即奥尔巴赫神经丛)Thesubserosalplexus浆膜下神经网丛,Whatarethethreenerveplexuses?,唾液saliva味蕾tastebuds嗅神经olfactorynerves胃液的分泌thesecretionofgastricjuice恒牙permanentteeth咀嚼mastication食管esophagus蠕动peristalsis外层纵向肌outerlongitudinallayersofmuscles内层环形肌innercircularlayersofmuscles,MouthandEsophagus口腔和食道,1.Threepairsofsalivaryglands1literofsalivaperday,salivation唾液分泌,1.Threepairsofsalivaryglands1literofsalivaperday2.Autonomicnervoussystem(自主神经系统)controlssalivation.(sympatheticandparasympathetic)(Butnotregulatedbyhormones),salivation唾液分泌,食糜chyme十二指肠duodenumThestomachsmajoranatomicboundaries:食管括约肌贲门胃大弯和胃小弯幽门括约肌十二指肠Whatarethefunctionalareasofthestomach?fundus,body,antrum,Stomach胃,胃壁stomachwall斜肌层alayerofobliquemuscle中环层和外纵层在胃底最薄Thecircularandlongitudinallayersofmusclearethinnestinthefundus.胃体和胃窦逐渐变厚Thelayersbecomeprogressivelythickerinthebodyandantrum.胃粘膜themucosaofthestomach,Stomach胃,1.血液通过腹腔一支动脉输入胃中Bloodissuppliedtothestomachbyabranchoftheceliacartery.2.主动脉沿胃大弯和胃小弯分布Majorarteriesliealongthegreaterandlessercurvatures.3.分叉深入浆膜和肌层branchandpenetratetheserosaandmusclelayers4.形成丰富的侧支循环formarichcollateralcirculation,Stomach胃,CardiovascularSystem:MajorVessels,1.renalartery肾动脉2.vertebralartery脊椎动脉3.subclavianartery锁骨下动脉4.aorta主动脉5.coronaryartery冠状动脉6.celiacartery腹腔动脉7.superiormesentericartery肠系膜上动脉8.lumbarartery腰动脉9.inferiormesentericartery肠系膜下动脉10.gonadalartery生殖腺动脉,renalartery肾动脉vertebralartery脊椎动脉3.subclavianartery锁骨下动脉4.aorta主动脉5.coronaryartery冠状动脉6.celiacartery腹腔动脉7.superiormesentericartery肠系膜上动8.lumbarartery腰动脉9.inferiormesentericartery肠系膜下动10.gonadalartery生殖腺动脉,Arichcirculation,stomach,liver,GastricVein,SplenicVein,静止状态下没有壁张力Inrestingstate,nowalltension.吞咽动作致使底部松弛Swallowingcausesthefundustorelax.食物存储在垂直层或斜纤层Foodisstoredinverticalorobliquelayers液体相对快速地流入胃窦Fluidsflowrelativelyquicklydowntotheantrum.蠕动波使胃动力开始增强Gastricmotilityincreaseswithperistalticwaves(蠕动收缩频率)同时受神经和激素活动影响。Influencedbyneuralandhormonalactivity.,GastricMotility胃运动,1.胃液或胃分泌物gastricjuicesorgastricsecretion2.粘液、酸、酶、激素和内因子Mucus,acid,enzymes,hormones,andintrinsicfactor3.激素被分泌到血液里Thehormonesaresecretedintotheblood.4.其他胃分泌物直接进入胃腔。Theothergastricsecretionsintothestomachlumen,GastricSecretion胃分泌,粘液形成一道防护屏障来抵御酸和蛋白水解酶。Mucusformsaprotectivebarrieragainstacidandproteolyticenzymes.,GastricSecretion胃分泌,1.胃液的成分取决于其体积和流动速度Thecompositionofgastricjuicedependsonvolumeandflowrate2.氢和氯,钠,钾的浓度变化Thechangeoftheconcentrationsofhydrogenandchloride,sodium,andpotassium3.分泌的速度和体积在早上为最小值，在下午和晚上达到最大值。Therateandvolumeofsecretionarelowestinthemorningandevening.,GastricSecretion胃分泌,Whatinhibitsgastricsecretion(胃分泌)?(L.95-96)Unpleasantodorsandtastes;Rage,fear,painWhatcausesincreasedsecretions?分泌物增多与敌对心理或敌意厌恶感有关.,GastricSecretion胃分泌,1.功能上可分为三部分：十二指肠，空肠和回肠Dividedinto3segments:theduodenum,jejunum,andileum2.腹膜是包裹在腹部器官和骨盆腔上的一层浆膜Theperitoneumistheserousmembranesurroundingtheorgansofabdomenandpelviccavity.,SmallIntestine小肠,Smallintestine,Ileocecalvalve,jejunum,Asuspensoryligament,duodenum,jejunum,Asuspensoryligament,腹膜,Peritoneum,Peritoneum,Mesentery,1.十二指肠的动脉供应主要由胃十二指肠动脉提供。Thearterialsupplytotheduodenumarisesprimarilyfromthegastroduodenalartery.2.小肠平滑肌分布为两层：外部的纵层和内部较厚的环层。Thesmoothmusclesofthesmallintestinearearrangedintwolayers.,SmallIntestine小肠,Arterialsupplytosmallintestine,Gastroduodenalartery,食物氯化氢和胃蛋白酶的作用(分解食物纤维和蛋白)食糜胰腺酶，肠道酶和胆盐的作用碳水化合物/蛋白质/脂肪分解水/维生素/电解液通过传输，扩散或易化扩散经肠道黏膜吸收。,IntestinalDigestionandAsborption肠道消化与吸收,小肠运动食糜刺激肠道运动混合有来自肝脏，胰腺和肠腺的分泌物搅拌运动腔内物接触到绒毛吸收细胞推进使食糜进入大肠ChymestimulatesintestinalmovementsMixinsecretionfromtheliver,pancreas,andintestinalglandsachurningmotionbringstheluminalcontentintocontactwiththeabsorbingcellsofthevilli.Advancethechymetowardthelargeintestine.,IntestinalMotility肠道运动,肠道运动受两种运动影响：结肠袋分节运动和蠕动。Intestinalmotilityisaffectedbytwomovements:Haustralsegmentationperistalsis,IntestinalMotility肠道运动,Thelargeintestineconsistsof:cecum盲肠apouchappendix阑尾vermiformcolon结肠rectum直肠analcanal肛管,LargeIntestine大肠,Thefourpartsofthecolonascendingcolon升结肠transversecolon横结肠descendingcolon降结肠sigmoidcolon乙状结肠,LargeIntestine大肠,肠内物通过盲肠和结肠受两个括约肌控制：theileocecalvalve回盲瓣控制食糜从回肠进入盲肠theOBeirnesphincter奥贝恩括约肌控制废物从乙状结肠进入直肠。2.analsphincters肛门括约肌internalanalsphincter肛门括约肌externalanalsphincter肛门括约肌,LargeIntestine大肠,Whatcausestokillpathogens(病原体)andbacteriathroughoutthegastrointestinaltract?AcidinthestomachBileacidsecretionIntestinalmotilityAntibodyproductionWhereareanaerobesmainlyfound?(L.196-197),IntestinalBacteria肠道细菌,AccessoryOrganofDigestion消化的辅助器官,Whataretheaccessoryorgansofdigestion?Liverproducesbilegallbladderstoresbileexocrinepancreasproducesenzymesneededforthecompletedigestionofcarbohydrates,proteins,andfats.Besides,producesanalkalinefluid.LiverItalsoreceivesnutrientsabsorbedbythesmallintestine,metabolizingandsynthesizing,AccessoryOrganofDigestion消化的辅助器官,Liver-SecretionofBileWhereistheliverlocated?L.2162.Themetabolicfunctionoftheliverrequirealargeamountofbloodhepaticartery(肝动脉)providesoxygenatedbloodportalvenousblood(门静脉血)constitutes70%ofthebloodsupplytotheliver.,AccessoryOrganofDigestion消化的辅助器官,Liver-SecretionofBileSecreting700to1200mlbileperdayWhatdoesthebilecontain?bilesaltscholestrolbilirubin,electrolyteswater胆盐、胆固醇、胆红素、电解液和水Whatisthefunctionofbilesalts?(L.233-235),AccessoryOrganofDigestion消化的辅助器官,Gallbladder(胆囊)PositionandFunctionHowdoesthebilemove?胆汁从肝脏流出，经由左或右肝导管进入肝总管，并在此遇到奥迪括约肌的阻力。奥迪括约肌掌控胆汁流入十二指肠。此后，胆汁经由胆管进入胆囊，并在此贮存、变浓。,AccessoryOrganofDigestion消化的辅助器官,Gallbladder(胆囊)3.HowdoesGallbladderwork?饭后30分钟内，胆囊开始收缩，奥迪括约肌松弛，迫使胆汁通过大的十二指肠乳突进入十二指肠。在口腔和胃消化阶段，迷走神经的类胆碱分支控制胆囊的收缩。胆囊收缩的荷尔蒙调节源于缩胆囊素和胃动素的释放，缩胆囊素和胃动素是在脂肪环境下十二指肠黏膜分泌的。,AccessoryOrganofDigestion消化的辅助器官,ExocrinePancreas(外分泌胰腺)LocationofPancreasWhyisthepancreasunique?Ithasbothendocrineandexocrinefunctions.3.Whatdoestheendocrinepancreas(内分泌胰腺)do?secreteshormones:insulin(胰岛素)glucagons(高血糖素),AccessoryOrganofDigestion消化的辅助器官,4.Whatdoestheexocrinepancreas(外分泌胰腺)do?secreteenzymes(酶)andalkalinefluids(碱性流体),AccessoryOrganofDigestion消化的辅助器官,Secretionsdrainintoasystemofductsthatleadstothepancreaticduct,whichemptiesintothecommonbileductattheampullaofVate.分泌物流入导管系统，导管系统通向胰导管，然后进入法特壶腹处的总胆管。,AccessoryOrganofDigestion消化的辅助器官,Insomeindividualsanaccessoryductbranchesoffthepancreaticductanddrainsdirectlyintotheduodenumatanopeningcalledtheminorduodenalpapilla.在某些个体中可见辅助性导管分支于胰导管，胆汁在被称为小的十二指肠乳突的开口处直接进入十二指肠。,
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