IOO 



ELEMENTARY PHYSIOLOGY 



those of the oesophagus, and are, in fact, continuations of them. 



The outer of these, which, of course, lies next the peritoneal 



coat, is muscular; the next 

 is composed of areolar tis- 

 sue, and the inner coat is a 

 mucous membrane. 



The muscular coat of 

 the stomach consists of 

 three sets of involuntary 

 muscular fibres. The outer 

 set run longitudinally from 

 the cardiac orifice to the 

 pylorus, and are continuous 

 with the longitudinal fibres 

 of the oesophagus. The 

 middle set of fibres encircle 

 all parts of the stomach, 

 and are especially numer- 

 ous at the pyloric end. 

 The inner set consist of 



Fig. 96. A Section through the Walls 

 of the Stomach. Magnified 15 dia- 

 meters. 



CZ 



oblique fibres. They are 



i, surface of the mucous membrane, showing the COntinUOUS with the cirCU- 



openings of .the peptic glands ; 2, mucous mem- i fikvpo nf rhf rp:rmri3O-ll<5 



brane, composed almost entirely of glands ; 3, sub- lar "DrCS Ot me CCSOpnagUS, 



mucous or areolar tissue ; 4, transverse muscular and exist chiefly at the Car- 



fo b ne e ai : c 5 oa! ngitudinal muscu ' ar fibres ' *' P * l[ ' diac end of the stomach. 



By means of these mus- 

 cles the contents of the stomach are kept in a continuous circular 

 motion, passing from the cardiac end to the pylorus along the 



greater curvature, and back 

 to the cardiac end along the 

 lesser curvature : and, as 

 with the oesophagus, these 

 motions are best maintain- 

 ed when the stomach is 

 moderately distended with 

 food - substances, so that 

 the muscles can grasp them 

 on all sides. 



The walls of the sto 

 mach are capable of great . 

 distension ; consequently 

 it can adapt itself to the 

 quantity of food it contains, 

 and, at the same time, be always in contact with the food so as to 

 act on it. 



Fig- 97- Muscular Coat of the Stomach. 



External layer of longitudinal fibres. 

 p, pylorus ; c, cardiac end ; CE, oesophagus. 



