Chapter 6 diGesTioN ABSORPTION §1. Introduction Concept of digestion absorption k Mechanical chemical digestion o Characteristics of digestive smooth muscles *k General characteristics k Electrophysiological characteristics Resting potential (rP) Slow wave or basic electrical rhythm (BEr) Action potential (AP)
Chapter 6 DIGESTION & ABSORPTION § 1. Introduction • Concept of digestion & absorption * Mechanical & chemical digestion • Characteristics of digestive smooth muscles * General characteristics * Electrophysiological characteristics Resting potential (RP) Slow wave or basic electrical rhythm (BER) Action potential (AP)
g 5 mv 0 (I) 35 Electrical activities contraction of digestive smooth muscles
Electrical activities & contraction of digestive smooth muscles
o Secretion of digestive glands k Main functions of digestive fluids o Gastrointestinal innervation k Intrinsic (or enteric) nervous system Submucosal myenteric plexus k Extrinsic nervous system Parasympathetic sympathetic nerves o Gastrointestinal hormones 米 General functions 米 Brain- gut peptides
• Secretion of digestive glands * Main functions of digestive fluids • Gastrointestinal innervation * Intrinsic (or enteric) nervous system Submucosal & myenteric plexus * Extrinsic nervous system Parasympathetic & sympathetic nerves • Gastrointestinal hormones * General functions * Brain-gut peptides
AAAUWM! 黏膜层 黏膜肌层 黏膜下层和 神经丛 ?环形肌层 肌间神经丛 }纵形肌层 传入纤维 浆膜层 交感神经 节后纤维 脊髓传入纤维 迷走神经传入 Intrinsic 和传出纤维 (or enteric nervous 节衔纤维 systen
Intrinsic (or enteric) nervous system
8 2. Digestion in the mouth esophagus ● Saliva& its function k Nature composition of saliva pH6.6~7.1,99% water Salivary amylase, lysozyme, salt, etc. *k Functions of saliva Moisten the cavity solve food; keep the mouth clean; anti-bacteria; digest starch k Regulation of salivary secretion Pure neuroregulation Conditioned unconditioned reflex
§ 2. Digestion in the mouth & esophagus • Saliva & its function * Nature & Composition of saliva pH 6.6~7.1, 99% water Salivary amylase, lysozyme, salt, etc. * Functions of saliva Moisten the cavity & solve food; keep the mouth clean; anti-bacteria; digest starch * Regulation of salivary secretion Pure neuroregulation Conditioned & unconditioned reflex
e Mastication or chewing its effects 米 Definition 米 Effects Break up large food particles; mixes the food with saliva; aid swallowing o Deglutition or swallowing *k Definition k Process Ist, 2nd 3rd phase Peristalsis lower esophageal sphincter
• Mastication or chewing & its effects * Definition * Effects Break up large food particles; mixes the food with saliva; aid swallowing • Deglutition or swallowing * Definition * Process 1st, 2nd & 3rd phase Peristalsis & lower esophageal sphincter
83. Digestion in the stomach e Gastric juice its secretion k Nature Compositions functions pH 0.9-1.5, colorless, 1.5-2.5 L/day Hydrochloric acid (HCl) Secreted by parietal cells Basic secretion: 0.5 mmol/h Max secretion: 20-25 mmol/h Mechanism of hcl secretion Functions: see next page
§ 3. Digestion in the stomach • Gastric juice & its secretion * Nature, Compositions & functions pH 0.9~1.5, colorless, 1.5~2.5 L/day Hydrochloric acid (HCl) Secreted by parietal cells Basic secretion: 0~5 mmol/h Max secretion: 20~25 mmol/h Mechanism of HCl secretion Functions: see next page