176 



ELEMENTARY PHYSIOLOGY 



hilus) of each kidney, a long tube with a small bore, the 

 Ureter (Ur.), proceeds to the Bladder (BL). 



The latter, situated in the pelvis, is an oval bag, the 

 walls of which contain abundant unstriped muscular fibre, 

 while it is lined, internally, by mucous membrane, and 

 coated externally by a layer of the peritoneum, or double 



Fig. 50. 



The kidneys (K); ureters (Ur.y; with the aorta (^o.) ; and vena cava 

 inferior (r.f./.) ; and the renal arteries and veins. Bl. is the bladder, 

 the top of which is cut off so as to show the openings of the ureters (1, 1) 

 and that of the urethra (2). 



bag of serous membrane which has exactly the same 

 relations to the cavity of the abdomen and the viscera con- 

 tained in them as the pleurse have to the thoracic cavity 

 and the lungs. The ureters open side by side, but at 

 some little distance from one another, on the posterior 

 and inferior wall of the bladder (Fig. DO, 1, 1). Each 



