BLADDER. 



429 



Bladder (Fig. 244). This is not infrequently spoken of as 

 the urinary bladder, and when moderately distended will contain 

 about ^ liter ; though it may be so distended as to contain very 

 much more than this. 



It has 4 coats : peritoneal or serous, muscular, submucous, and 

 mucous. The muscular coat is made up of 3 layers of plain 

 muscular fiber : External or longitudinal, middle or circular, and 

 internal, which is also longitudinal. The external longitudinal 

 layer is also described as the detrusor urince muscle, and the aggre- 



FIG. 244. Section of penis, bladder, etc. : 1, symphysis puhis ; 2, prevesical 

 space; 3, abdominal wall; 4, bladder; 5, urachus; 6, seminal vesicle and vas 

 deferens ; 7, prostate ; 8, plexus of Santorini ; 9, sphincter vesicse ; 10, suspensory 

 ligament of penis; 11, penis in flaccid condition; 12, penis in state of erection ; 13, 

 glans penis ; 14, bulb of urethra ; 15, cul-de-sac of bulb, a, Prostatic urethra ; b, 

 membranous urethra; c, spongy urethra (Testut). 



gation of the fibers of the circular layer around the neck of the 

 bladder and the beginning of the urethra, as the sphincter vesicce. 

 The mucous coat or mucous membrane is covered with transitional 

 epithelium, and contains racemose glands. 



Nerve-supply. The nerves supplying the bladder are, according 

 to Langley and Anderson, derived from (1) the second to the fifth 

 lumbar nerves, reaching the organ through the sympathetic chain, 

 the inferior mesenteric ganglion, and the hypogastric nerves ; (2) 

 the second and third sacral spinal nerves. Stimulation of the 



