Stomach• Simple columnar epithelium, no villi or gobletcells• Mucosa is thrown into irregular folds = rugae• Three layers of smooth muscle (additionaloblique layer)• Gastric pits and gastric glands in mucosa

Ruga Mucosa

Submucosa

Muscularisexterna

Serosa

Organization(more review)

StomachCell types:• Mucous epithelial cells (1)• Mucous neck cells• Parietal cells (2)• Zymogenic cells (3)

Gastric pit

Gastric gland

1

3

2

Small intestine – general features• Simple columnar epithelium with goblet cells that increase in number distally• Plicae circulares – large folds of mucosa and submucosa• Villi – finger like projections of the mucosa (epithelium and lamina propria) into thelumen• Crypts of Lieberkuhn – projections of lumen into mucosa

Plica circularis Several villi Two villi

Duodenum• Brunner’s glands in submucosa • Simple columnar• Villi are relatively long, but wide• very few goblet cells

Brunner’s glandsLacteal

Jejunum• No glands or lymphatic tissue in submucosa• villi are very long and skinny• number of goblet cells greater than duodenum

Ileum• Numerous discrete patches of lymphatictissue in the submucosa (Peyer’s patches)• villi are short and squat• many goblet cells

Peyer’s patch

Colon (Large intestine)• Simple columnar with many goblet cells, no villi, but intestinal crypts• No fecal concretions• Sometimes concentrated lymphatic nodules

Lymphaticnodule

Tenia coli