Structures in the Four Layers

• ORGAN: Esophagus

  LAYER: Mucosa

  • Nonkeratinized Stratified squamous epithelium
  • Lamina Propria
  • fine connective tissue
  • blood vessels
  • lymphatic nodule
  • excretory ducts of mucous acini of esophageal glands proper
  • Muscularis Mucosa
  • smooth muscle
• ORGAN: Esophagus

  LAYER: Submucosa

  • Dense irregular connective tissue
  • Excretory ducts of Mucous Acini of Esophageal Glands Proper
  • Adipose tissue
  • Veins and Arteries
• ORGAN: Upper Esophagus

  LAYER: Muscularis Externa

  • Inner Circular Muscle Layer (Skeletal)
  • Outer Longitudinal Muscle Layer (Skeletal)
• ORGAN: Upper & Middle Esophagus

  LAYER: Adventitia

  • Connective Tissue purely
  • Adipose tissue
  • Blood vessels
  • Nerve fibers
• ORGAN: Middle Esophagus

  LAYER: Muscularis Externa

  • Inner Circular Muscle Layer (Skeletal-Smooth)
  • Outer Longitudinal Muscle Layer (Skeletal-Smooth)
• ORGAN: Lower Esophagus

  LAYER: Muscularis Externa

  • Inner Circular Layer (Smooth)
  • Outer Longitudinal Layer (Smooth)
• ORGAN: Lower Esophagus

  LAYER: Serosa

  • Connective tissue layer lined with simple squamous mesothelium
• ORGAN: Stomach

  PART: Cardia

  LAYER: Mucosa

  • Surface Epithelium
  • Simple Columnar Epithelium
  • Gastric Pits
  • Cardiac Glands
  • Lamina Propria
  • Mucosal Ridges
  • Lymphatic nodules
  • Muscularis Mucosae
  • Inner circular
  • Lymphatic nodule 
  • Outer longitudinal
• ORGAN: Stomach

  PARTS: Cardia, Fundus and Body

  LAYER: Submucosa

  • Dense irregular connective tissue 
  • And MORE collagen fibers than lamina propria
  • Lymph vessels
  • Capillaries
  • Arterioles
  • Venules
  • Submucosal Meissner Nerve Plexus
• ORGAN: Stomach

  PARTS: Cardia, Fundus and Body

  LAYER: Muscularis Externa

  • Oblique layer
  • Circular layer
  • Myenteric Auerbach Nerve Plexus (between circular and longitudinal)
  • Longitudinal layer
• ORGAN: Stomach

  PARTS: Cardia, Fundus and Body

  LAYER: Serosa

  • Simple squamous mesothelium of visceral peritoneum
  • Adipose cells
• ORGAN: Stomach

  PARTS: Fundus and Body

  LAYER: Mucosa

  • Surface Epithelium
  • Simple Columnar Epithelium
  • Gastric Pits 
  • Gastric Glands
  • Isthmus
  • Parietal Cells
  • Neck
  • Mucous neck cells
  • Base or Fundus
  • Chief (zymogenic) cells
  • Enteroendocrine cells
  • Stem cells
  • Lamina Propria
  • Reticular and Collagen fibers
  • Mucosal Ridges
  • Fibroblast
  • Lymphatic nodule
  • Lymphocytes
  • Loose CT cells
  • Muscularis Mucosae 
  • Inner circular
  • Outer Longitudinal 
  • Submucosa
  • Denser CT
  • Collagen fibers
  • Fibroblasts
  • Arterioles and Venules
  • Lymphatics
  • Capillaries
  • Adipose Cells
• ORGAN: Stomach

  PARTS: Pylorus

  LAYER: Submucosa

  • Dense irregular CT
  • Blood vessels
• ORGAN: Stomach

  PARTS: Pylorus

  LAYER: Mucosa

  • Surface Epithelium
  • Simple Columnar Epithelium
  • Gastric Pits
  • Pyloric Glands
  • Lamina Propria
  • Lymphatic Nodule
  • Muscularis Mucosae
  • Inner circular
  • Lymphatic nodule 
  • Outer longitudinal
• ORGAN: Stomach

  PARTS: Pylorus

  LAYER: Muscularis Externa

  • Oblique
  • Circular
  • Forms Pyloric Sphincter at pyloric-duodenal junction
  • Longitudinal
• ORGAN: Small Intestine

  PARTS: Duodenum and Jejunum

  LAYER: Mucosa

  • Lining epithelium with columnar cells
  • Plicae circularis 
  • Villi 
  • Striated Brush Borders
  • Goblet Cells
  • Lamina Propria
  • Intestinal Glands (Crypts of Lieberkuhn)
  • Paneth cells
  • Enteroendocrine or APUD cells
  • Lacteals
  • Lymphatic nodules
  • Muscularis Mucosae
• ORGAN: Small Intestine

  PARTS: Duodenum

  LAYER: Submucosa

  • Duodenal (Brunner’s) Glands
• ORGAN: Small Intestine

  PARTS: Duodenum, Jejunum, and Ileum

  LAYER: Muscularis Externa

  • Inner Circular
  • Myenteric (Auerbach) Nerve Plexus
  • Outer Longitudinal
• ORGAN: Small Intestine

  PARTS: Ileum

  LAYER: Mucosa

  • Surface epithelium
  • Villi
  • Lamina Propria
  • Intestinal glands
  • Lacteals 
  • Peyer Patches
  • Muscularis Mucosae
  • Peyer Patches
• ORGAN: Small Intestine

  PARTS: Ileum

  LAYER: Submucosa

  • Extension of Peyer Patches
• ORGAN: Large Intestine

  PARTS: Colon

  LAYER: Mucosa

  • Simple Columnar Epithelium
  • Absorptive columnar cells 
  • Goblet cells 
  • Lamina Propria 
  • Intestinal glands 
  • Lymphatic nodules
  • Muscularis Mucosae
• ORGAN: Large Intestine

  PARTS: Colon

  LAYER: Submucosa

  • CT cells
  • Blood vessels and nerves
• ORGAN: Large Intestine

  PARTS: Colon and Rectum

  LAYER: Muscularis Externa

  • Inner Circular 
  • Continuous
  • Myenteric (Auerbach) Nerve Plexus 
  • Outer Longitudinal
  • Taeniae Coli
• ORGAN: Large Intestine

  PARTS: Appendix

  LAYER: Mucosa

  • Lining epithelium
  • Goblet cells
  • Lamina Propria
  • Intestinal Glands
  • Diffused lymphatic tissue
  • Lymphatic Nodules with Germinal Centers
  • Muscularis Mucosae
• ORGAN: Large Intestine

  PARTS: Appendix

  LAYER: Submucosa

  • Diffuse lymphatic tissue
• ORGAN: Large Intestine

  PARTS: Appendix

  LAYER: Muscularis Externa

  • Inner Circular
  • Myenteric (Auerbach) Nerve Plexus
  • Outer Longitudinal
• ORGAN: Large Intestine

  PARTS: Rectum

  LAYER: Mucosa

  • Simple Columnar Epithelium
  • Striated borders
  • Goblet cells
  • Lamina Propria 
  • Intestinal glands
  • Adipose cells
  • Lymphatic nodules
  • Muscularis Mucosae
• ORGAN: Large Intestine

  PARTS: Rectum

  LAYER: Submucosa

  • Temporary folds
  • Upper
  • Permanent folds
  • Lower 
  • Blood vessels
• ORGAN: Large Intestine

  PARTS: Rectum

  LAYER: Adventitia (portion)/Serosa (the rest)

  • Blood vessels
• ORGAN: Large Intestine

  PARTS: Anus (Anorectal Junction)

  LAYER: Mucosa

  • Simple columnar to stratified squamous
  • Lamina Propria
  • Intestinal Glands 
  • Lymphatic nodules 
  • Muscularis Mucosae
  • Internal Hemorrhoidal Plexus
• ORGAN: Large Intestine

  PARTS: Anus (Anorectal Junction)

  LAYER: Submucosa

  • Continuing blood vessels of internal hemorrhoidal plexus
• ORGAN: Large Intestine

  PARTS: Anus (Anorectal Junction)

  LAYER: Muscularis Externa

  • Internal Anal Sphincter
  • Smooth
  • Upper
  • External Anal Sphincter
  • Skeletal
  • Lower
  • Levator Ani muscle
• What cell secretes somatostatin?

  D cells