四川大学：《医学生理学》课程教学资源（PPT课件讲稿）胃肠生理学 Gastrointestinal physiology（岳利民）

Gastrointestinal physiology Yue limin(岳利民) Department of Physiology School of preclinical and Forensic Medicine Sichuan University

Gastrointestinal physiology Yue Limin(岳利民) Department of Physiology School of Preclinical and Forensic Medicine Sichuan University

The old saying you are what you ea you are what you absorb and digest tid conque Jaw Teeth Oesophagi Stomach Gallbladder. Pancreas Large intestine Small intestin Transverse colo Jejunum Descending cold Ilium Sigmoid color Rectum Anus

The old saying "you are what you eat" "you are what you absorb and digest

Introduction Concepts of digestion and absorption Characteristics of the smooth muscle of gastrointestinal tract Secretory function of digestive gland Neural control of gastrointestinal tract Endocrine function of gastrointestinal tract

Introduction Characteristics of the smooth muscle of gastrointestinal tract Neural control of gastrointestinal tract Secretory function of digestive gland Endocrine function of gastrointestinal tract Concepts of digestion and absorption

I Concepts of digestion and absorption The main types of foods pCarbohydrads, fat, protein--large molecules p Vitamine, inorganic salt, water-small molecules fiber

Ⅰ. Concepts of digestion and absorption The main types of foods Carbohydrads, fat , protein large molecules Vitamine, inorganic salt, water small molecules fiber

Digestion: M The breakdown of proteins, fats and carbohydrates into absorbable molecules in the gastrointestinal tract Protein -amino acid Carbohydrate-monosaccharide Fat--fatty acid and glycerol Absorption: nk The movement of the digested products water and electrolytes from the lumen of digestive tract into the lymph or the blood closed relationship between digestion and absorption

Digestion: The breakdown of proteins, fats and carbohydrates into absorbable molecules in the gastrointestinal tract. Absorption: The movement of the digested products ,water and electrolytes from the lumen of digestive tract into the lymph or the blood. Protein amino acid Carbohydrate monosaccharide Fat fatty acid and glycerol closed relationship between digestion and absorption

How are the foodstuffs digested

How are the foodstuffs digested ?

Mechanical Digestion The motility of smooth muscle in gastrointestinal tract grinds food and mixes it with digestive juice to prepare it for chemical digestion and absorption, and then propels the food along the gastrointestinal tract. Chemical Digestion: Nutrients in the food are broken down by the enzymes in digestive juice secreted by the secretory glands

Mechanical Digestion: The motility of smooth muscle in gastrointestinal tract grinds food and mixes it with digestive juice to prepare it for chemical digestion and absorption, and then propels the food along the gastrointestinal tract. Chemical Digestion: Nutrients in the food are broken down by the enzymes in digestive juice secreted by the secretory glands

I. Characteristics of Gastrointestinal Smooth muscle 1. General physiological characteristics >low excitibility >slow contractility > high extensibility >tonicity >Sensitive for chemical, thermal and mechanical stretch stimulation

1. General physiological characteristics Ⅱ.Characteristics of Gastrointestinal Smooth Muscle ➢low excitibility ➢high extensibility ➢tonicity ➢Sensitive for chemical, thermal and mechanical stretch stimulation ➢slow contractility

2. Electrophysiological characteristics +Resting potential +Slow wave potential rAction potential Relationship between Electrical Activity and Contractile Activity SPIKES Electrical Threshold Threshold for contraction SLOW WAVES

2. Electrophysiological characteristics Slow wave potential Action potential Resting potential

Resting potential of smooth muscle In gi Value:-50---60mV Formation out flow of K+: Nat ca2+ electrogenic Nat-K pump

Resting potential of smooth muscle IN GI Value: -50 -60mV Formation: out flow of K+ ; Na+ Ca2+ electrogenic Na+ -K+ pump