THE METABOIJC MACHINERY OF ANIMALS 



289 



the lower end is known as the pyloric part, the extreme Hmit of which 

 is indicated by a groove called the pylorus. The pyloric and fundic 

 parts of the stomach differ in the nature of their musculature as well 

 as in their physiological activity during digestion. The pyloric part 

 is separated from the small intestine by a sphincter muscle, called the 

 sphincter pylorus. The shape and position of the stomach may \'ary 

 according to the posture and amount of food ingested. Thus, while 

 the stomach is supposed to lie in an "obliquely transverse position," 



Cocrdiac region. 

 funcLus 



-T^egion. 



£oT2_ 



ga-s bubble 



.CarcCiac 

 region 



intermecCiate 

 portioi-x 



ctuocCsr2Ltri>. 



pyloras-j^ 



pyloric 



The human stomach (1) as usually depicted, (2) the shape and position of the 

 stomach as shown by X-ray, (3; stomach and large intestine showing position of 

 food at varying hours after ingestion. (After Howell.) 



it really assumes a J-shape as detected by X-rays. The folded wall 

 of the fundus is dotted with thousands of tiny pits, the mouths of 

 gastric glands, or little tubes the epithelial lining of wliich secretes 

 the gastric juice. (See page 294.) 



As in the case of the remainder of the digestive tract, the stomach 

 wall is made up of several layers of tissue. Beginning with the inside 

 is the soft, thick, glandular mucosa, usually thrown into folds, or 

 rugae, which tend to disappear when the stomach is distended. 

 A second layer, the submucosa, composed of loose connective tissue 



