THE DIGESTIVE SYSTEM 



81 



brown area containing the fundus glands. The rest of the mucous 

 membrane is reddish-gray in color and contains the pyloric glands. 

 The muscular layer is composed of involuntary fibers arranged in 

 longitudinal, circular, and oblique fashion. The serous layer is 

 a reflexion of the peritoneum 

 and is continuous with the great 

 omentum. 



The stomach of the ox is so 

 large that it fills the entire left 

 half of the abdominal cavity 

 and a part of the right half 

 (Fig. 23). It is compound and 

 consists of [four compartments, 

 viz., rumen or paunch, reticulum 

 •or honeycomb, omasum or many- 

 plies, and abomasum or true 

 stomach (Fig. 24.) The capacity 

 of the four divisions is 30 to 45 

 gallons, the rumen constituting 

 about 80 per cent. The lining 

 membrane and arrangement of 

 each division differs in appear- 

 ance to correspond with the par- 

 ticular kind of work which it has 

 to perform. The interior of the 

 rumen presents long papilla, but 

 has no secretory glands; the 

 reticulum has a honeycomb- 

 like lining; the omasum has 

 about 100 longitudinal folds 

 or leaves; the abomasum has 

 secretory glands like those in 

 the fundus region of the horse's 

 stomach and resembles the 

 stomach of animals having but one compartment. 



The small intestine of the horse is a tube averaging about 1J£ 

 inches in diameter and 75 feet long, originating at the stomach 

 and ending at the cecum. It is arbitrarily divided into the 

 duodenum, jejunum, and ileum. The first part is about three to 

 four feet long and is fixed, while the other parts are floating. It 



6 



Digitized by Microsoft® 



s . 



o 



"-J 



Fig. 25. — Longitudinal section of 

 the small intestine. The submucous 

 coat consists of connective tissue 

 and contains the larger blood-vessels, 

 f rom which the mucous and muscular 

 coats are supplied with blood. (From 

 Hough and Sedgwick's The Human 

 Mechanism, by permission of Ginn 

 and Company, Publishers.) 



