The digestive tract is a long, continuous tube of varying diameter extending from the lips to the anus. It includes oral cavity,esophagus, stomach,

The digestive tract is a long, continuous tube of va

rying diameter extending from the lips to the anus. It i

ncludes oral cavity,esophagus, stomach, small intestin

es, large intestine and appendix.

The oral cavity

The oral cavity is lined by mucosa. There are a ton

gue and 32 permanent teeth in the oral cavity.

Fig． 1．

Fig． 2．

Except the oral cavity, the wall of the digesti

ve tract consists of four layers: mucosa, submuc

osa, muscularis and adventitia. The mucosa cons

ists of epithelium, lamina propria and muscularis

mucosa.

Fig ． 3 ． Cross section of esophagus(HE stain,low mag.)

Tunicamuscularis

submucosa

mucosa

Fig ． 4 ． Stomach (HE stain,low mag.)

mucosa

submucosa

Tunicamusculari

s

Fig ． 5 ． Stomach(HE stain,high mag.)

Gastric pit

Gastric gland

Parietal cell

Parietal cell

Neck mucous

cell

Fig ． 6 The mucosa of gastric fundus : fundic glands

Fig 7． Parietal cell

Active cell

Resting cell

Fig． 8 parietal cell

Chief cellsChief cells

Fig ． 9 The mucosa of gastric fundus : fundic glands

Fig． 10

Chief cell

ZG:

Zymogen gr

anules

The small intestines include duodenum ,

jejunum and ileum. There are plica circulare

s and villi on the mucosa of the small intesti

nes.

Villus

Fig ． 11 Small intestine (jejunum)

Striated border

Fig ． 12 Villus of small intestine(HE stain ,high mag.)

Central lacteal

Goblet cell

Columnar cell

Fig ． 13 Villus of small intestine(HE stain ,high mag.)

Central lacteal

Striated border

Fig． 14 absorptive cell

Fig ． 15 small intestine gland

Paneth cell:

acidophilic granules

Fig． 16 P

aneth cell:

Secretory gr

anules

Fig ． 11 Longitudinal section of Colon(HE stain,low mag.)

Tunica muscularis

mucosa

submucosa

Intestinal gland

epithelium

Fig 12 Mucosa of Colon (HE stain,high mag.)

Fig 13 Mucosa of Colon (HE stain,high mag.)

Intestinal gland

Fig ． 14 Cross section of appendix(HE stain ,low mag.)

Arrowhead:lymphoid nodule

Intestinal gland

muscularis mucosa