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1、第八章 消化系统,第一节 概述,一、消化系统的组成和功能二、消化管的一般结构 三、消化管平滑肌的生理特性,一、消化系统的组成和功能,消化（digestion）：食物通过消化管的运动和消化液的作用被分解为可吸收成分的过程。Digestion Breakdown of food molecules for absorption into circulation 机械性消化 Mechanical:Breaks large food particles to small化学性消化 Chemical:Breaking of covalent bonds by digestive enzymes,一、消化
2、系统的组成和功能,组成消化管消化腺功能消化食物吸收营养排出残渣内分泌功能免疫功能,二、消化管的一般结构,（一）黏膜1.上皮2.固有层3.黏膜肌层（二）黏膜下层（三）肌层（四）外膜,三、消化管平滑肌的生理特性,（一）兴奋性（二）伸展性（三）紧张性（四）自动节律性（五）对理化刺激的敏感性,四、消化腺的分泌功能,消化液：水，无机盐，有机物，消化酶消化液的功能：分解食物适宜的pH环境稀释食物保护消化管黏膜,第二节 消化器官的形态结构,一、消化管 二、消化腺,消化器官,Digestive tract(mouth to anus)Alimentary tract or canalGI tract(stom
3、ach and intestines)Accessory organsPrimarily glandsRegionsMouth or oral cavityPharynxEsophagusStomachSmall intestineLarge intestineAnus,一、消化管,（一）口腔（二）咽（三）食管（四）胃（五）小肠（六）大肠,（一）口腔,1.口唇2.颊3.腭4.舌5.牙,舌,功能咀嚼吞咽发音感受味觉舌乳头轮廓乳头菌状乳头叶状乳头丝状乳头,牙 Teeth,两副牙乳牙（6月6岁）恒牙（6岁13岁）形态和功能切牙尖牙前磨牙磨牙,牙 Teeth,外形牙冠牙颈牙根,（三）食管,食管的三个狭
4、窄处起始部越过左支气管处穿膈肌处食管狭窄的生理意义,（四）胃,1.胃的位置、形态与分部2.胃壁的结构,胃 Stomach,胃的解剖,上下两口喷门幽门大小两弯胃大弯胃小弯前后两壁,Located in the left superior abdomen,胃的组织结构,胃壁黏膜黏膜下层肌层浆膜胃襞胃区胃小凹胃腺喷门腺幽门腺胃底腺,胃底腺细胞主细胞（胃酶细胞）分泌蛋白酶原壁细胞（泌酸细胞）分泌盐酸，内因子颈黏液细胞，分泌黏液幽门括约肌,（五）小肠,1.小肠的分部2.小肠壁的结构特点（1）环状襞（2）黏膜上皮（3）小肠绒毛（4）肠腺,小肠的分部,十二指肠空肠回肠,十二指肠的组织结构,Modificat
5、ionsThe mucosa and submucosa form a series of folds(Circular folds or plicae)At the top of each fold are located villi which are covered in microvilliLacteal capillary network,（六）大肠 Large Intestine,盲肠 cecum,结肠colon,直肠rectum,肛管anal canalMovements sluggish(18-24 hours),大肠的组织结构,Circular muscle layer ar
6、ound the colon is complete,but the longitudinal layer is not.3 bands called teniae coli(a band of tape runs the length of the colon)Contraction of the teniae coli causes pouches of 结肠袋 haustra to draw up,二、消化腺,（一）唾液腺（二）胰（三）肝,唾液腺 Salivary Glands,唾液腺腮腺下颌下腺舌下腺,（三）肝,1.肝的位置和形态2.肝的结构3.肝的血液循环4.肝的功能5.胆囊与输胆管
7、道,肝的结构,分叶 Lobes左叶，右叶肝门Ducts肝管肝固有动脉门静脉前有胆囊后有下腔静脉,Portal triad Hepatid portal vein,artery,and duct,肝索 Hepatic cordsContain hepatocytes,the functional cell of the liverBile productionStorageInterconversion of nutrientsDetoxificationPhagocytosisSynthesis of blood Spaces between the cords are sinusoids.B
8、ile canaliculus lies btw the cells within each cord,肝的功能,分泌胆汁代谢功能防御和解毒功能造血功能,导管系统,胆囊 Gallbladder,胆囊管 Cystic duct connects gallbladder to common bile duct胆汁 Bile is stored and concentratedStimulated by 胆囊收缩素cholecystokinin and vegal stimulationDumps large amounts of concentrated bile into small intes
9、tineProduction of 胆结石 gallstones possibleDrastic dieting with rapid weight loss,第三节 消化,一、口腔内的消化二、胃内消化三、小肠内消化 四、大肠内消化,一、口腔内的消化,（一）唾液1.性质和成分2.唾液的作用（1）湿润溶解食物（2）清洁保护口腔（3）杀灭细菌和毒素（4）中和胃酸保护胃黏膜（5）唾液淀粉酶,一、口腔内的消化,（二）咀嚼与吞咽1.咀嚼（mastication）的作用（1）切碎磨细食物（2）混合成食团（3）化学性消化（4）刺激感受器，引起胃、胰、肝、胆囊等器官活动的加强2.吞咽（swallowing）,
10、二、胃内消化,（一）胃液的性质、成分和作用1.盐酸2.胃蛋白酶原3.黏液和碳酸氢盐4.内因子,二、胃内消化,（二）胃的运动1.胃的运动形式（1）容受性扩张（2）紧张性收缩（3）蠕动2.胃排空3.呕吐,胃的运动,三、小肠内消化,（一）胰液的成分和作用（二）胆汁的成分和作用（三）小肠液的成分和作用（四）小肠的运动,（一）胰液的成分和作用,1.胰淀粉酶2.胰脂肪酶3.胰蛋白酶和麋蛋白酶,（二）胆汁的成分和作用,胆盐的作用加强脂肪酶的活性和脂肪酸结合形成水溶性的复合物，促进脂肪酸和脂溶性维生素的吸收乳化脂肪,（三）小肠液的成分和作用,稀释消化产物，有利于吸收肠致活酶，激活胰蛋白酶原,（四）小肠的运动,
11、1.紧张性收缩2.分节运动3.蠕动,小肠的运动,四、大肠内消化,（一）大肠的分泌物及细菌活动（二）大肠的运动与排便1.大肠的运动2.排便,第四节 吸收,一、吸收部位二、几种主要营养物质的吸收,几种主要营养物质的吸收,（一）糖的吸收单糖是糖类在小肠中吸收的主要形式（二）蛋白质的吸收蛋白质被分解成氨基酸后才能被小肠吸收（三）脂肪的吸收脂肪的消化产物与胆盐形成混合微胶粒（淋巴液和血液）（四）水和无机盐的吸收水和盐吸收的主要部位在小肠，大肠吸收食物残渣（五）维生素的吸收维生素（水溶性，脂溶性）,Carbohydrates,Consist of starches,glycogen,sucrose,lac
12、tose,glucose,fructosePolysaccharides broken down to monosaccharidesMonosaccharides taken up by active transport or facilitated diffusion and carried to liver Glucose is transported to cells requiring energyInsulin influences rate of transport,Lipids,Include triglycerides,phospholipids,steroids,fat-s
13、oluble vitaminsEmulsification breaks down large lipid droplets to small,Lipoproteins,TypesChylomicronsEnter lymphVLDLLDLTransports cholesterol to cellsHDLTransports cholesterol from cells to liver,Proteins,Pepsin breaks proteins into smaller polypeptide chainsProteolytic enzymes produce small peptid
14、e chainsDipeptides,tripeptides,amino acids,Water and Ions,WaterCan move in either direction across wall of small intestine depending on osmotic gradientsIonsSodium,potassium,calcium,magnesium,phosphate are actively transported,第五节 消化器官活动的调节,一、神经调节二、体液调节,一、神经调节,（一）消化器官的神经支配和作用双重神经支配，以副交感神经的作用为主（二）消化器
15、官活动的反射性调节1.非条件反射性调节2.条件反射性调节,Reflexes in Colon and Rectum,Functions,1.Secratin in one location2.Alternating contraction and relaxation of tract3.Material spread out in both directions4.Secretion of chyme spread out in tract and becomes more diffused through time,Mixing:Segmental contraction that occ
16、urs in small intestineSecretion:Lubricate,liquefy,digestDigestion:Mechanical and chemicalAbsorption:Movement from tract into circulation or lymphElimination:Waste products removed from body,Blood and Bile Flow,Digestive Tract Histology,Digestive tube consists of four major layers or tunics from the
17、esophagus to the anus.Three glands are associated with the tract.Unicellular mucous(mucosa)Multicellular(mucosa and submuxossa)Multicellular accessory glands(Outside the digestive tract),二、体液调节,（一）胃肠激素1.胃泌素2.胰泌素3.胆囊收缩素4.肠抑胃素（二）其他化学物质的调节（三）消化器官活动的完整性,腹膜和肠系膜,腹膜 PeritoneumVisceral:Covers organsParietal
18、:Covers interior surface of body wallRetroperitoneal:Behind peritoneum as kidneys,pancreas,duodenum(no mesenteries)肠系膜 MesenteriesHold organs in placeRoutes which vessels and nerves pass from body wall to organs.,大网膜 Greater omentum extends from greater curvature and transverse colon小网膜 Lesser omentum connects the lesser curvature of the stomach and the proximal end of the duodenum of the liver and diaphragm,
