Digestive tract

Dark C Taste pore Light C Taste bud

circumvallated papillae（HE） filiform and fungiform papillae （ HE）

Foliate papillae-taste bud （HE） Tongue foliate papillae（HE） Taste pore

● mucous membrane of tongue Lingual papillae: filiform, fungiform & circumvallated. Tast bud: dark C, light C & basal C.

General structure of the wall 1.mucosa: epithelium: Lamina propria: Muscularis mucosa: 2.submucosa: 3.Muscularis externa: 4.adventitia:

4sub 1Epi. mucosa 2lamina propria 4esophageal glands 3 muscula ris mucosa 5outer longi tudinal M 5inner circular M 6 adven titia Esophagus （HE）

epithelium Esophageal gland Esophagus

2.sbumucosa: esophageal glands, mucous. Esophagus 1.mucosa: ● Epi.: stratified squamous. Non-keratinized ● lamina propria: CT. ● muscularis mucosa: boudles of SMC.longitudinal 2.sbumucosa: esophageal glands, mucous. 3.muscularis: inner circular, outer longitudinal 4.adventitia: fibrosa. upper1/3: skeletal M. middle: mixed. Lower1/3: smooth M.

Stomach

fundus

Stomach mucosa: submucosa: LCT. Simple columnar Epi.: surface mucous cell Lamina propria: gastric pit, gastric glands Muscularis mucosa: inner circular, outer longitudinal. submucosa: LCT. muscularis: inner oblique, middle circular, outer longitudinal. Adventitia: serosa.

fundic glands location：lamina propria compositions： 1.Chief C 2.Parietal C 3.Neck mucous C 4.Endocrine C 5.Stem C

Chief cells Secretory granule nucleus rER LM: Lower columnar; basophilic; Nucleus located in the lower parts. Secretory granules. EM: Gol , Apical of the nucleus; mit. & rER ,basal part of cytoplasm; Secretory granules, apical of cytoplasm. Function : pepsinogen

Parietal cells microvilli LM: C large，cone-shaped or round. nucleus Introcellular canaliculi Mitochondria LM: C large，cone-shaped or round. acidophilic. Nucleus is round ,centrical. EM Introcellular secretory canaliculi & microvilli. Tubulovesicular system. Mit. are abundant. functions: Hcl & intrinsic factor.

duodenum ileum jejunum small intestine

1 striated border Central lacteal 1 absorbtive C SMC 2 goblet C Cap. 5 stem C Intestinal gland 3 Paneth C 4 endocrine C

villi folds submucosa muscularis adventitia Intestinal villi

microvilli （striated border）

Small intestine mucosa: Epi.: simple columnar, absorbtive C + goblet C. Lamina propria: small intestinal gland ,central lacteal. Muscularis mucosa: inner circular, outer longitudinal. villi: the finger-like processes composed of epithelium layer and lamina propria protruding into the lumen .

submucosa The duodenal gland, mucosa. Circular folds: mucosa&submucosa protruding into the lumen . Appears as processes. muscularis: inner circular,outer longitudinal . adventitia: serosa.

@@@@@small intestinal gland Absorbtive C Goblet C Endocrine C Stem C Paneth C LM: the base of gland. arranged in groups of 3-5 cells . in the apex, coarse acidophilic granules. EM: protein-secreting cell. functions: produce lysozyme.

Large intestinal

Epi. Lamina propria Large intestinal gland Muscularis mucosa （goblet C） Lamina propria Muscularis mucosa Mucosa of large intestine（HE）

Large intestine mucosa: no villi ,no circular folds. Simple columnar Epi.: abundant goblet C. Lamina propria: large intestinal glands, no paneth C. Muscularis mucosa:

appendix No villi, intestinal gland Is scanty. Lamina propria: abundant LT. Serosa

The comparisons between mucosa of variant digestive tract （1） Small intestine Large intestine esophagus stomach surface Gastric pit villus Striated squamous Simple columnar Simple columnar Striated border Goblet C Simple Columnar Goblet C abundant Epi.

The comparisons between mucosa of variant digestive tract （2） esophagus stomach Small intestine Large intestine Lamina propria No glands Gastric gland Small intestinal gland Large intestinal gland No L nodule L nodule L nodule abundant lacteal Fundic gland of stomach: chief , parietal, neck mucous , endocrine, stem C. Small intestinal gland: absorbtive, goblet, paneth, endocrine, stem C. Large intestinal gland: absorbtive, goblet, endocrine, stem C.

Key points Structure characteristics of variant digestive tract. The similar and the different. Esp, the variance of tunica mucosa. Such as , the villi and the glands.

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