浙江大学医学院：《组织学和胚胎学》课程教学资源（PPT课件）Chapter 13 消化道 Digestive tract

Histology Embryology Digestive tract Li Zhong Jie(李仲杰)，Ph.D School of Medicine,Zhejiang University 20151106

Digestive tract Li Zhong Jie（李仲杰）, Ph. D School of Medicine,Zhejiang University 20151106

Histology Embryology Mouth salivary gund Digestive system Summand bula ° Digestive tract ° Digestive gland -Digestive system function Stomach llbladder This system is responsible for the mechanical and chemical break down of food material, and for absorbing Smah these digestive products into the blood for use as nutrients by the individual cells and tissues of the body Anal canal

---Digestive system: • Digestive tract • Digestive gland ---Digestive system function: This system is responsible for the mechanical and chemical break down of food material, and for absorbing these digestive products into the blood for use as nutrients by the individual cells and tissues of the body

Histology Embryology The Digestive Process Ingestion Mechanical Pharyn Taking in food through the mouth Chewing(mouth) Churning(stomach) Propulsion(movement of food) Propulsion (small intestine Swallowing (or Peristalsis Peristalsis -propulsion by alternate Chemical (esophagus digestion stomach contraction relaxation ing Intestine. Mechanical digestion Chewing Churning in stomach CoabSorption Mixing by segmentation ANAACNJ Chermical digestion vessel Carbohydrates, Fat, and Proteins are broken Small down by enzymes Blood ● Absorption Lar vess Transport of digested end products into Mainly Ho blood and lymph in wall of canal Feces Defecation Defecation Elimination of indigestible substances from Anus body as feces

The Digestive Process • Ingestion – Taking in food through the mouth • Propulsion (movement of food) – Swallowing – Peristalsis – propulsion by alternate contraction & relaxation • Mechanical digestion – Chewing – Churning in stomach – Mixing by segmentation • Chemical digestion – Carbohydrates, Fat, and Proteins are broken down by enzymes. • Absorption – Transport of digested end products into blood and lymph in wall of canal • Defecation – Elimination of indigestible substances from body as feces

Histology Embryology ° Chemica| digestion Complex food molecules(carbohydrates, proteins and lipids) broken down into chemical building blocks(simple sugars, amino acids and fatty acids and glycerol) Carried out by enzymes secreted by digestive glands into lumen of the alimentary canal

• Chemical digestion --- Complex food molecules (carbohydrates, proteins and lipids) broken down into chemical building blocks (simple sugars, amino acids, and fatty acids and glycerol) --- Carried out by enzymes secreted by digestive glands into lumen of the alimentary canal

Histology Embryology Components of digestive tract ---oral cavity -pharynx --esopnagus h stomac small intestine -large intestine -rectum and anus

Components of digestive tract ---oral cavity ---pharynx ---esophagus ---stomach ---small intestine ---large intestine ---rectum and anus

Histology Embryology General plan of digestive tract Except for oral cavity and pharynx, all other organs share a similar histological plan Submucosal Nerve plexus Gland in submucosa Meeney 1. Mucosa Duct from 2. Submucosa 3. Muscularis externa Mucosa submucosa Muscularis Serosa Circular Connective 4 Adventitia epithelium muscle tssue amana propn LongitudinallPeritoneum Muscularis muscle from lumen(inside)out

General plan of digestive tract ---Except for oral cavity and pharynx, all other organs share a similar histological plan 1. Mucosa 2. Submucosa 3. Muscularis externa 4. Adventitia from lumen (inside) out

Histology Embryology Inner layer: the mucosa x (mucous membrane) Three sub-layers epithelium Mucosa: Epithelium lamina propria(may Lamina propria Muscularis mucosae contain glands) Muscularis mucosae (Smooth muscle) Gland in mucosa Duct of gland outside alimentary canal

Inner layer: the mucosa* (mucous membrane) Three sub-layers – epithelium – lamina propria (may contain glands) – Muscularis mucosae (Smooth muscle) *

Histology Embryology surface 1, Epithelium two types stratified squamous simple columnar epith 2、 Lamina propria LCT. contained small glands, blood lymph capillaries. mucosa-associated lymphoid tissue 3. Muscularis mucosa inner circular/outer longitudinal layer depth of smooth muscle cells

Mucosa 1. Epithelium -------two types stratified squamous & simple columnar epith. 2. Lamina propria LCT. contained small glands，blood & lymph capillaries. mucosa-associated lymphoid tissue 3. Muscularis mucosa inner circular / outer longitudinal layer of smooth muscle cells. depth surface

Histology Embryology the submucosa米 Submucosal nerve plexu LCT with small blood Gland in submucosa lymphatic vessels; glands only in the esophagus and Submucosa duodenum Submucosal( meissner autonomic) nerve plexus Duct of gland outside alimentary can

the submucosa* * – LCT. with small blood / lymphatic vessels; * glands only in the esophagus and duodenum – Submucosal ( Meissner’s autonomic) nerve plexus

Histology Embryology THAINTE五 Pica afford of mucosa and submucosa y MM ongitudinal/ circular form CM LM 南W

GI Plica *a fold of mucosa and submucosa *longitudinal/circular form