Stomach Histology Lecture Notes

Overview

• The stomach is a critical part of the gastrointestinal (GI) tract, located between the esophagus and duodenum.
• Functions of the stomach:
  • Mixes food with stomach acid.
  • Breaks food down into smaller particles through chemical and mechanical digestion.

Layers of the Stomach Wall

1. Mucosa

   • Surface Mucous Cells: Simple columnar epithelium that secretes alkaline, viscous mucus.
   • Gastric Pits: Invaginations that connect to gastric glands, lined with surface mucous cells.
   • Gastric Glands: Produce digestive enzymes and mucous secretions; types include cardiac, gastric, and pyloric glands.
   • Lamina Propria: Connective tissue containing blood and lymphatic vessels.
   • Muscularis Mucosa: Two layers of smooth muscle aiding gland secretion discharge.

2. Submucosa

   • Composed of connective tissue, contains the submucosal (Meissner's) plexus.
   • Provides parasympathetic innervation stimulating digestion.

3. Muscularis Externa

   • Smooth muscle with three layers: inner oblique, middle circular, outer longitudinal.
   • Produces churning movements for mechanical digestion.
   • Contains the myenteric (Auerbach's) plexus for neural control.

4. Serosa

   • Outermost layer, made of mesothelium and connective tissue.
   • Lubricates and allows smooth movement in the abdominal cavity.

Mnemonics

• M.S.M.S for the layers: Mucosa, Submucosa, Muscularis externa, Serosa.
• SMP & MAPS mnemonic:
  • Submucosal: Meissner's, Parasympathetic.
  • Myenteric: Auerbach's, Parasympathetic, Sympathetic.

Gastric Glands and Cells

• Gastric Gland Regions:
  • Fundus/Body: Rich in digestive enzyme-producing parietal and chief cells.
  • Pyloric/Cardiac: Abundant in mucous neck cells protecting against gastric juices.
• Cell Types:
  • Mucous Neck Cells: Secrete mucus less alkaline than surface epithelial cells.
  • Stem Cells: Replace damaged cells.
  • Parietal (Oxyntic) Cells: Secrete intrinsic factor and HCl.
  • Chief (Zymogenic) Cells: Secrete pepsinogen and gastric lipase.
  • Enteroendocrine Cells: Release gastrin into the blood.

Functions and Features of Stomach Layers

• Mucosa: Secretes mucus; protects against abrasion and acid.
• Submucosa: Rich vasculature and lymphatics, supports nerve plexus.
• Muscularis Externa: Supports mechanical digestion; contains nervous plexus for muscle control.
• Serosa: Provides lubrication and protection.

Learning Resources

• Kenhub Resources: Videos, quizzes, and HD atlas for enhanced learning.
• Structured content with academic and peer-reviewed validation.

Additional Information

• The article emphasizes the importance of histology in understanding digestive processes and structural details of the stomach.
• Offers various study materials to facilitate learning, including mnemonic devices and interactive quizzes.

Note: This guide is meant for educational purposes and reflects insights from Kenhub's comprehensive anatomy resources.