THE BLADDER. 213 



plays a thick mucous membrane lying chiefly in longitudinal 

 folds ; at the lower part, these are called the columns of 

 Morgagni, and are generally three in number. The mus- 

 cular fibres are longitudinal and circular ; the longitudinal 

 cease at the lower part, and give place to the circular fibres 

 which form the internal sphincter. 



THE BLADDER. 



The rectum must now be removed. The ureter and vas deferens 

 are to be followed to their terminations. The peritoneum should be 

 dissected from off the bladder. * 



* 



The BLADDER, when distended, is of an ovoid shape, the 

 summit or superior end being the smaller ; it is connected 

 <ith the penis by a somewhat funnel-shaped portion, called 

 neck. In the male, the neck is surrounded by the pros- 

 tate ; in the female, the place of this is supplied by cellular 

 ind muscular tissue. The summit of the bladder termi- 

 lates in the urachus, the remains of a canal, called the 

 llantois, which, during the early part of foetal life, con- 

 iccted the bladder and the umbilical aperture. 



In addition to the serous, the bladder has a muscular 

 tnd a mucous coat, united together by cellular tissue. The 

 ibres of the muscular coat are arranged both in a circular 

 id a longitudinal manner; the circular fibres are chiefly 

 found round the neck, and constitute what is called the 

 sphincter vesicse ; the longitudinal are well marked, both 

 in front and behind, and, from their office, are named, col- 

 lectively, the detrusor urinse. 



The mucous coat of the bladder is thrown into folds, or 

 becomes smooth, according to the degree of its distension. 

 At the lower and anterior part of its interior is the orifice 

 of the urethra, the aperture of which is partly closed by a 

 small mucous projection, called the uvula vesicse. By 

 blowing through the ureters, their orifices will be demon- 

 strated, as well as the obliquity with which they penetrate 

 the bladder. The triangle formed lay these two orifices, 

 and the orifice of the bladder, is called the trigonum vesicx, 

 and is made apparent by the greater adhesion of the mucous 

 membrane to the parts beneath than elsewhere. Especially 

 in a hypertrophied condition of the muscular coat of the 

 bladder, two muscular bands, proceeding from the orifices 

 of the ureters, may be seen, on lifting the mucous coat, 

 converging towards the urethral orifice ; closely united 



