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