156 STUDENTS HISTOLOGY 



mucosa. (e) Muscular layers. (Only a portion of the inner 

 circular layer is shown. It has been divided transversely.) 



(H.) 



2. The epithelium of gland-tubes. (The upper portion of the 

 tubes will be cut obliquely in many places, as they have been 

 inclined, and the epithelium will show as a beautiful mosaic of 

 polygonal areas.) (a) The differentiation between border and 

 central cells. (&) Tubes cut transversely, showing the.lumina. 

 (c) Indications of the capillary plexuses between the tubes. 



3. The mucosa. () Arterioles and venules beneath the 

 tubules. (6) Scattered lymphoid cells (round cells with one, two, 

 or three nuclei). 



4. Lenticular glands, masses of adenoid or lymphoid tissue at 

 the bottom of the mucous membrane, chiefly near the pylorus. 



5. The muscularis mucosae. (Note the elongated nuclei of 

 the smooth muscle-cells.) 



6. The submucosa. (a) Arteries, veins, etc., cut in various 

 directions. (6) The adipose tissue. (Fat-crystals are frequently 

 seen in the cells when freshly mounted.) 



7. The muscular bundles of the circular layer with the septa 

 of connective tissue. (Note particularly the various appearances 

 presented by bundles of involuntary muscular fiber when cut in 

 different planes.) 



8. Groups of ganglion cells belonging to the plexuses of Auer- 

 bach or Meissner will occasionally be seen on very careful 

 examination. 



SMALL INTESTINE 



The histology of the intestines, both large and small, is formed 

 upon the general plan of that of the stomach. The same layers 

 are presented: the mucosa, with its epithelial covering; the muscu- 

 laris mucosce; the submucosa; the muscular and peritoneal coats. 



The mucosa of the small intestine is everywhere pierced by 

 blind depressions; and the surface is studded with minute eleva- 

 tions or papillae, between which are the depressions which corre- 

 spond to the tubules of the stomach. The elevations are called villi, 

 the depressions between the villi, the crypts of Lieberkiilm. 



The small intestine serves two important functions: 1. The 

 secretion of a fluid, one of the digestive juices the succus enteri- 

 cus. 2. The absorption of food, especially the fats or hydrocarbons. 



