THE CAT 219 



accumulation of fat. On the medial side of the kidney is the 

 slight concavity called the hilus, where the ureter and renal vein 

 leave it and the renal artery enters it. The artery enters the 

 body of the kidney ; the branches of the vein will be seen on its 

 outer surface. 



The ureter is a long tube, which passes along the dorsal body 

 wall on one side of the vertebral column from the kidney to the 

 dorsal surface of the neck of the bladder. It has the appearance 

 of a white cord and is often embedded in fat. Its anterior end is 

 called the pelvis; this is a funnel-shaped sac, the large end of 

 which is embedded in the kidney and catches the urine as it oozes 

 from the mouths of the kidney tubules; its small end emerges 

 from the hilus as the ureter proper. In the male animal the two 

 ureters, near their hinder ends, pass through the loops made by 

 the two vasa deferentia. 



Remove the fat from the kidney and the ureter on the right side 

 of the animal ; be careful not to cut the ureter or any of the veins 

 or arteries near it. The large median vein between the kidneys 

 is the postcaval vein ; the large median artery is the dorsal aorta. 

 The renal vein and the renal artery on each side will also be seen. 



The urinary bladder is a muscular, pear-shaped sac which lies 

 in the hinder part of the abdominal cavity between the rectum 

 and the ventral body wall. Its larger end is directed forward ; its 

 smaller end, the neck, receives the ureters and is directed back- 

 ward. In the male animal the neck is continued in the form of 

 the urethra, or urogenital canal, and receives the vasa deferentia, 

 which bring spermatozoa from the testes. It passes through the 

 penis, at the distal end of which is the external opening, and 

 becomes the common outlet for both urinary and genital organs. 

 In the female the neck of the bladder opens into the urogenital 

 sinus, or vestibule, a short, wide- space, which receives also the 

 vagina and is equivalent to the urogenital canal of the male; it 

 opens to the outside through the vulva. 



The bladder is supported by three mesenteries,— the median, 

 ventral suspensory ligament, and the two lateral ligaments, which 

 join it with the dorsal body wall. 

 Exercise 12, Draw a semidiagrammatic sketch of the urinary system. 



