ISO ANATOMY OF THE DOMESTIC FOWL 



reaction of the contents of the small intestine is strongly acid, but ' 

 gradually less so in proportion to the distance down the intestinal 

 tract until the caeca are reached, where the reaction is found to be 

 faintly acid, neutral, or slightly alkaUne. 



Function. — The function of the small intestine is that of digestion 

 and absorption. 



The Duodenum. Location and Shape. — The duodenum, a small 

 tube, originates from the gizzard about 3^ inch to the right of 

 the entrance of the proventriculus. Extending from left to right, 

 it passes imder and behind the gizzard along the inner side of the 

 right abdominal wall backward to the posterior portion of the wall, 

 and a trifle more than half way toward the left side, where-the loop 

 rests. This loop, the duodenal loop, is about 5 inches in length (Fig. 

 31, No. 8). The two branches of the loop the first and the second 

 portions or the descending and ascending limbs, are loosely held by 

 connective tissue, and have the pancreas lodged between them. 



The Free Portion of the Small Intestine. Location. — That sec- 

 tion of the small intestine following the duodenum is called the free 

 portion of the small intestine and occupies the space between the 

 abdominal air-sac and the median line of the abdominal cavity. 

 It is disposed in coils and is suspended from the dorsal wall of the 

 abdomen by a thin membrane, the mesentery. 



The bile ducts enter the small intestine about 14 inches frOm 

 its point of origin. The pancreas also pours its contents into the 

 small intestine. 



The Large Intestine (Fig. 31, No. 12). Location. — The large 

 intestine extends in a straight line along the inferior border of the 

 vertebral column communicating anteriorly with the small intestine, 

 and the caeca and posteriorly with the cloaca. 



Shape. — The diameter of the large intestine is approximately 

 twice that of the small intestine. In fowls of average size its mean 

 length is j^^^lJagbes. The large intestine has sometimes been spoken 

 of as the rectum, or straight gut. 



Structure. — ^Like the small intestine the large intestine has four 

 coats: an inner mucous, a submucous, a middle muscular and an 

 outer serous. The folds of mucous membrane of the large intestine 

 have tubular glands hned with columnar cells (Fig. 37, j4 No. i). 



Function.- — The large intestine is similar in function to that of the-^ 

 small intestine, in that digestion and absorption may take place 

 within it. 



