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