1、消化与吸收Digestion and Absorption夏 强，PhD浙江大学医学院生理学系电话：88206417,88208252Email：两个概念 消化是指食物中所含的营养物质在消化道内被分解为可吸收的小分子物质的过程 机械性消化 化学性消化 吸收食物经消化后形成的小分子物质，以及维生素、无机盐和水通过消化道黏膜上皮细胞进入血液和淋巴的过程 消化系统 消化道 消化腺消化系统的功能 运动Movement 分泌Secretion 消化Digestion 吸收Absorption 排出EliminationStructure of the alimentary canalNormal BER
2、 frequencies in the gastrointestinal system基本电节律basic electrical rhythm:BER两套神经系统 肠（内在）神经系统 Enteric nervous system(intrinsic)自主（外来）神经系统 Autonomic nervous system(extrinsic)胃肠激素Gastrointestinal hormones 消化道内所含的内分泌细胞数远大于体内所有内分泌腺所含的细胞总数 消化道是目前所知的体内最大的内分泌器官 Gastrointestinal hormones，Gut hormones口腔内消化咀嚼和吞
3、咽Mastication and swallowingThe swallowing reflex is coordinated by the medulla oblongata,which stimulates the appropriate sequence of contraction and relaxation in the participating skeletal muscle,sphincters,and smooth muscle groups.The coordinated sequence of contraction and relaxation in the uppe
4、r esophageal sphincter,the esophagus,and the lower esophageal sphincter is necessary to deliver swallowed food to the stomach.胃内消化 胃的主要功能：暂时储存食物 消化食物 少量吸收 胃液Gastric juice成分 HCl 胃蛋白酶原Pepsinogen 黏液Mucus 碳酸氢盐HCO3-内因子Intrinsic factor pH 0.9-1.5黏液-碳酸氢盐屏障Mucus-HCO3-barrier幽门螺旋杆菌(Helicobacter Pylori)胰液分泌Pa
5、ncreatic secretion 胰液 pH 7.88.4 1500 ml/day Isosmotic Components:Pancreatic digestive enzymes:secreted by pancreatic acini Sodium bicarbonate:secreted by small ductules and larger ducts Secretion of pancreatic digestive enzymes Carbohydrates-Pancreatic amylase Pancreatic lipase Fat Cholesterol ester
6、ase Phospholipase Trypsinogen Proteins Chymotrypsinogen Procarboxypolypeptidase Proelastase急性胰腺炎Acute pancreatitis胆汁分泌Secretion of bile by the liver 胆汁的成分 HCO3-Bile salts Phospholipids Cholesterol Bile pigments 胆汁的功能：Emulsifying or detergent function of bile salts Bile salts help in the absorption o
7、f:Fatty acid Monoglycerides Cholesterol Other lipidsBig Droplets of FatSmall Droplets of FatMicellesFatty Acids andMonoglyceridesChylomicron AssemblyDistribution and ProcessingPreventing the cholesterol precipitation&gallstones 大肠的功能 吸收水分和无机盐 吸收微生物合成的维生素B复合物和维生素K 完成对食物残渣的加工，形成并暂时储存粪便In the large int
8、estine,active transport of sodium,coupled with osmotic absorption of water,are the primary activities.Microbes here are active in the production of vitamin K.排便反射Defecation reflex体 温Body Temperature体 温 恒温动物保持正常的体温是机体进行新陈代谢和生命活动的必要条件 核心温度Core temperature 表层温度Shell temperatureNormal core temperatureSi
9、teMean value of temperatureStandard deviationRange of variation of temperatureAxillary36.79oC0.35736.0-37.4 oCOral37.19 oC0.24936.7-37.7 oCRectal37.47 oC0.25136.9-37.9 oCThe circadian(“about a day”)rhythm of body temperature persists even among patients in a coma;in addition to this basic rhythm,fev
10、ers,exercise,and other activities can alter the body temperature.Body temperature is a controlled variable that is subject to homeostatic regulation.This cartoon indicates some of the ways that environmental factors can increase or decrease body temperature.体温调节 自主性体温调节Autonomic thermoregulation 行为性
11、体温调节Behavioral thermoregulation体温中枢主要在下丘脑Hypothalamus肾脏生理学Renal Physiology肾脏的功能 调节水和电解质平衡，调节体液渗透压 调节酸碱平衡 排出机体代谢终产物及进入体内的过剩物质和异物 糖异生 内分泌：促红细胞生成素（erythropoeitin）肾素（renin）1,25-二羟胆骨化醇（1,25-OH2-D3）其他：激肽，前列腺素（PGE2,PGI2）尿生成的三个基本过程 滤过Filtration 重吸收Reabsorption 分泌SecretionSubstance X is filtered and secreted
12、 but not reabsorbed.Substance Y is filtered and some of it is reabsorbed.Substance Z is filtered and completely reabsorbed.Composition in the Filtration FluidStructure of the Filtration Membrane葡萄糖的重吸收 正常情况下，全部重吸收 小管葡萄糖最大转运率Tm-G:Tubular transport maximum for glucose 肾糖阈Renal threshold for glucose Cr
13、itical value of the plasma glucose concentration when the kidney begins to excrete glucose 160-180 mg/dL尿量 正常：1000-2000ml/24hr 多尿Polyuria：2500ml/24hr 少尿Oliguria：400ml/24hr，或17ml/hr 无尿Anuria：100ml/24hr，或12hr完全无尿抗利尿激素Antidiuretic hormone(ADH)又称血管升压素Vasopressin 下丘脑合成 垂体后叶释放 作用：促进远曲小管和集合管对水的通透性 收缩血管Acti
14、on of antidiuretic hormone on aquaporin(AQP)transport.AC,adenylate cyclase;AP1,transcription factor;AVP,arginine vasopressin;cAMP,cyclic adenosine monophosphate;CRE,cAMP response element;CREB-P,CRE binding protein;EP3,prostaglandin receptor;PGE2,prostaglandin E2.(From Brown D,Nielsen S:The cell biol
15、ogy of vasopressin action.In Brenner BM ed:Brenner and Rectors The Kidney,7th ed.Philadelphia,WB Saunders,2004,p 574.)水利尿Water diuresis尿崩症Diabetes insipidusIn a kidney-failure patient undergoing dialysis,the blood is briefly removed from the body to be circulated through a dialyzer,where dialysis fluid and blood move in counter current directions to remove nitrogenous and other wastes and adjust osmolarity before the blood is returned to the body.血液透析Hemodialysis腹膜透析Peritoneal dialysis谢谢！谢谢！
