430 



DIGESTIVE SYSTEM OF THE DOG 



the eleventh or twelfth rib. In this state there is not rarely a marked constriction 

 between the right and left portions. 



The longitu(Unal muscular fibers are found on the curvatures and on the pyloric 

 part. The oblique fil)ers are arranged in two layers: the external layer is a con- 

 tinuation of the longitudinal fibers of the oesophagus onto the body and fundus. 

 The circular layer covers the whole stomach except the fundus, and forms a pyloric 

 sphincter and an antral sphincter. The internal oblique layer is arranged as in 

 the horse, and forms a similar loop-like, cardiac sphincter. 



Three regions of the mucous membrane exist. Cardiac glands are found in a 

 very narrow pale zone around the cardiac opening, and also scattered along the les- 

 ser curvature. The fundus gland region has a thick, reddish-brown mucous mem- 



FiG. 335. — Ahdominaij Viscera op Dog. 

 Superficial ventral view after removal of the great omentum. From photograph of formalin-harileneil siuhject. 



brane, which lines about two-thirds of the organ. The pyloric mucous membrane 

 is thinner and pale; in the dead subject it is often stained by regurgitated bile. 



THE INTESTINE 



The intestine is short — about five or six times the length of the body. 



The small intestine has an average length of about thirteen feet (ca. 4 meters). 

 It occupies most of the abdominal cavity behind the liver and stomach. The duod- 

 enum begins at the portal fissure and passes backward and upward, at first on the 

 visceral surface of the liver, then in contact with the right flank. Near the pelvis 

 it turns inward and sharply forward, passes along the inner border of the left 

 kidney, and joins the jejunum to the left of the root of the mesenter5\ The 

 mesoduodenum is given off from the conunon mesentery; it is a relatively wide 



