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, 88208252 Email：xiaqiang@zju.edu.cn

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Elimination

Structure of the alimentary canal

Normal BER 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

咀嚼和吞咽 Mastication and swallowing The 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 upper 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 pH 0.9-1.5 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 Pancreatic secretion

胰液 pH 7.8~8.4 ~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 esterase 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 of: Fatty acid Monoglycerides Cholesterol Other lipids

Big Droplets of Fat Small Droplets of Fat Micelles Fatty Acids and Monoglycerides Chylomicron Assembly Distribution and Processing

Preventing 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 intestine, 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 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 temperature

Normal core temperature Site Mean value of temperature Standard deviation Range of variation of temperature Axillary 36.79oC 0.357 36.0-37.4 oC Oral 37.19 oC 0.249 36.7-37.7 oC Rectal 37.47 oC 0.251 36.9-37.9 oC

The circadian (“about a day”) rhythm of body temperature persists even among patients in a coma; in addition to this basic rhythm, fevers, exercise, and other activities can alter the body temperature.

This cartoon indicates some of the ways that 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. Why no heat radiating from the person’s body surface? Is room temp = body temp?

体温调节 自主性体温调节Autonomic thermoregulation 行为性体温调节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Secretion

Substance X is filtered and secreted but not reabsorbed. Substance Y is filtered and some of it is reabsorbed. Substance Z is filtered and completely reabsorbed.

Composition in the Filtration Fluid

Structure 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: 肾糖阈Renal threshold for glucose Tubular transport maximum for glucose 肾糖阈Renal threshold for glucose Critical 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

Action of antidiuretic hormone on aquaporin (AQP) transport Action 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 biology of vasopressin action. In Brenner BM [ed]: Brenner and Rector‘s The Kidney, 7th ed. Philadelphia, WB Saunders, 2004, p 574.)

水利尿Water diuresis 尿崩症Diabetes insipidus

血液透析Hemodialysis In 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.

腹膜透析Peritoneal dialysis

谢谢！