Chap. XVII] 



URINARY SYSTEM 



331 



Fig. 169. — Diagram show- 

 ing Method of Entrance of 

 THE Ureter into the Bladder. 

 (Gerrish.) 



THE URETERS 



The ureters are the excretory ducts of the kidneys. They con- 

 sist of a distended portion called the pelvis, which is contained 

 within the kidney, and a duct. Each duct is about the diameter 

 of a goose-quill, and from twelve to eighteen inches (300 to 

 450 mm.) long. They consist of three 

 coats : — 



(1) An inner or mucous coat con- 

 tinuous above with that of the pelvis 

 of the kidney, and below with that 

 of the bladder. 



(2) A middle or muscular coat 

 which is arranged in two layers, an 

 inner longitudinal, and an outer cir- 

 cular. 



(3) An outer or fibrous coat which 

 carries the blood-vessels and nerves 

 with which the tube is supplied. 



Function. — The ureters connect the kidneys with the bladder 

 and serve as a passageway to convey urine from the kidneys to 

 the bladder. 



BLADDER 



The bladder is a hollow muscular organ situated in the pelvic 

 cavity behind the pubes, in front of the rectum in the male, and in 

 front of the anterior wall of the vagina, and the neck of the uterus, 

 in the female. It is a freely movable organ, but is held in position 

 by ligaments. During infancy it is conical in shape and projects 

 above the upper border of the pubes into the hypogastric region. 

 In the adult, when quite empty, it is placed deeply in the pelvis ; 

 when slightly distended, it has a round form ; but when greatly 

 distended, it is ovoid in shape and rises to a considerable 

 height in the abdominal cavity. It is customary to speak of the 

 widest part as the fundus, and the part where the bladder becomes 

 continuous with the urethra as the neck, or cervix. It has four 

 coats : — 



1. The mucous membrane lining the bladder is continuous 

 with that of the ureters and the urethra. When the bladder 

 is empty, the mucous membrane is thrown into irregular rugae. 



