CHAPTER IX. 

 URINARY SYSTEM. 



THIS system consists of the kidneys, ureters, bladdei 

 and urethra. The action of these organs is to deal 

 with the urine or what is commonly called the water 

 of the animal, which is a watery fluid secreted by 

 the kidneys. It varies in color, according to the condition of 

 the animal's blood. 



1. The Kidneys are two in number — one on the right 

 side and one on the left side, and are situated just below 

 the small of the back — the right one being the furthest ahead. 

 In shape, they are long and narrow, and resemble the liver 

 in color. In cutting one of the kidneys open, it is found to 

 be full of glands and tubes, which secrete the urine from the 

 blood while it is passing through the kidneys. These tubes 

 pass to the center of the kidneys, where they empty the urine 

 into what is called the pelvis. The glands are largely sup- 

 plied with blood vessels and nerves. The use of the kidneys 

 are to secrete the urine from the blood, which contains a 

 large amount of what is known as ureaic acid, and if not 

 taken out of the blood by these glands, acts as poison to the 

 system. 



2. The Ureters are the tubes which carry the urine down 

 from the pelvis of the kidney to the bladder. They are two 

 in number — one situated on the right side of the pelvic or hip 

 cavity and the other on the left side close to the walls — and 

 they enter one on each side at the upper part of the bladder. 

 They are only about the size of an ordinary straw. 



3. The Bladder is situated in the pelvic or hip cavity. 

 When it is full it sometimes stretches out into the abdominal 

 or belly cavity. It consists of a body and neck. The body 

 is the large part, and is placed in front ; the neck being at the 

 back part of the bladder. This is where the urine or water 

 passes out of the bladder. The bladder is made up of three 

 coats, somewhat similar to that of the bowels. The serous 

 coat is a continuation of the serous coat found in the belly 



67 



