DIGESTIVE APPARATUS 61 



extends from the stomach to the cecum, at which point the large 

 intestine begins. 



The stomach, and the small and large intestine have the same 

 three coats : inner mucous, middle muscular, and outer serous. 



The mucous coat in the small intestines is thickly studded 

 with villi. Various intestinal glands furnish fluids which assist 

 in digestion. 



The muscular coat is composed of two sets of fibers; those of 

 one set encircle the bowel, and those of the other set run length- 

 wise. This arrangement is for the purpose of producing peri- 

 staltic action of the intestines, i.e., the writhing movements 

 seen in dissection work or in butchering when the warm 

 intestine is quickly removed and exposed to the air. 



The outer coat is the peritoneum, a serous membrane which 

 lines the abdominal cavity and also covers the various abdomi- 

 nal organs. 



The liver is the largest gland in the body, weighing about 11 

 pounds, and is situated in the abdominal cavity on the right 

 side and well forward against the diaphragm. It manufactures 

 about 12 pounds of bile in 24 hours. The liver of the horse 

 shows three fairly distinct lobes, namely, the left, right and 

 middle. The liver is inclosed in a strong capsule called Glis- 

 son's capsule. The cow has a gall bladder but the horse has 

 none, and from the horse's liver, bile flows more or less con- 

 stantly into the intestine. Bile aids somewhat in digestion of 

 fats ; it has a slight cathartic effect ; it aids absorption and tends 

 to prevent putrefaction. The liver cells convert sugar received 

 from the blood into animal starch (glycogen), and store it up 

 as such, and finally they reconvert this glycogen into a soluble 

 sugar and give it out to the blood in proportion as the blood 

 loses its sugar. One of the most important functions of the liver 

 is to remove or else make harmless, various poisons which origi- 

 nate in the body and are taken to the liver by the blood. Also 

 the bile aids the pancreatic enzymes. 



Pancreas. — The pancreas is much smaller than the liver, weigh- 

 ing only about 17 ounces, but is said to furnish about 11 pounds 

 of pancreatic fluid daily. It is located in the abdominal cavity 

 below the posterior aorta and behind the stomach and liver. 

 The ends are called head and tail ; it is long, ti-iangular and 

 much like a big salivary gland. Pancreatic fluid empties into 

 the intestine at or near the bile duct. This fluid contains four 



