山东大学：《医学生理学 Medical Physiology》课程教学资源（PPT课件讲稿，人体生理学 Human Physiology）Chapter 6 Gastrointestinal Physiology Gastrointestinal Regulation and Motility Part I Introduction

Chapter 31 Gastrointes坤 rEgulation and motility

1 Chapter 31 Gastrointestinal Regulation and Motility

Nutrition We require > carbohydrates(mainly glucose) proteins(essential amino acids) >fats(but Western diet fats too high) >vitamins >minerals Carbohydrate Intake(normally 3000 50 Protein 6000kcal per day depends on 15% Geography Fat 35% Occupation

2 We require: ➢carbohydrates (mainly glucose) ➢proteins (essential amino acids) ➢fats (but Western diet fats too high) ➢vitamins ➢minerals Nutrition Carbohydrate 50% Fat 35% Protein 15% Intake (normally 3000- 6000kcal per day & depends on Geography Occupation

Oral cavity Gastrointestinal T Sublingual salivary gland system Esophagus consists of Gastrointestinal (Gitract Gallbladder Accessory glandular organs Duodenun Large inte st ine Anal canal

3 Gastrointestinal system consists of Gastrointestinal (GI) tract Accessory glandular organs

Anatomy and functions of the entract GI tract Parotid salivary gland mouth, pharynx Mouth Sublingual salivary gland Pharynx esophagus, Trachea stomach, small intestine Submandibular salivary- glar Esophagus large intestine. anus Accessory glandular Stomach Organs Gallbladde Pancreas Small intestine salivary glands, liver Colon gallbladder, pancreas Cecum intestine Rectum Anus

4 Anatomy and functions of the GI tract GI tract mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus Accessory Glandular Organs salivary glands, liver, gallbladder, pancreas

Histology/organization of the Gut Wall From esophagus to anus, gi tract has the same basic arrangement of tissues There are 4 layers that can be distinguished Mucosa Submucosa Muscularis Serosa

5 Histology/organization of the Gut Wall From esophagus to anus, GI tract has the same basic arrangement of tissues. There are 4 layers that can be distinguished • Mucosa • Submucosa • Muscularis • Serosa

Layers of Alimentary Canal Submucosa Mucosa ircular muscle layer S eros Longitudinal muscle layer

6 Layers of Alimentary Canal Serosa Submucosa Mucosa Circular muscle layer Longitudinal muscle layer

Layers of Alimentary Canal Myenteric plexus Serosa Mucosa Submucosal plexus c Longitudinal Submucosa muscle Circular muscle

7 Serosa Mucosa Submucosa Longitudinal muscle Circular muscle Layers of Alimentary Canal Myenteric plexus Submucosal plexus

1. Digestion of food and absorption of nutrients are accomplished in a long tube connected to the r external world at both ends 2. Secretion and motility of the tube are major themes in understanding the gut

8 1.Digestion of food and absorption of nutrients are accomplished in a long tube connected to the external world at both ends 2.Secretion and motility of “the tube” are major themes in understanding the gut

Processing of food by the ds 1. Ingestion: process of eating 2. Propulsion: passing of food down the gi tract swallowing: voluntary peristalsis: reflex, involuntary, involves alternating contractions of muscles in body walls of Gi organs 3. Mechanical digestion prepares food for chemical digestion includes chewing, mixing with saliva by tongue action, churning in stomach

9 1. Ingestion : process of eating 2. Propulsion : passing of food down the GI tract • swallowing : voluntary • peristalsis : reflex, involuntary, involves alternating contractions of muscles in body walls of GI organs 3. Mechanical digestion • prepares food for chemical digestion • includes chewing, mixing with saliva by tongue action, churning in stomach... Processing of food by the DS

Processing of food by the DS 4. Chemical digestion catabolic steps in which food is broken down to basic building blocks accomplished by enzymes in digestive juices 5. Absorption: passage of food particles into the blood lymph 6. Defecation: elimination of indigestible food substances 10

10 4. Chemical digestion • catabolic steps in which food is broken down to basic building blocks • accomplished by enzymes in digestive juices 5. Absorption : passage of food particles into the blood￾lymph 6. Defecation: elimination of indigestible food substances Processing of food by the DS