300 OF THE URINE. 



human subject in different parts,* and inserted into the 

 posterior and inferior surface of the bladder in such a 

 way, that they do not immediately perforate its sub- 

 stance, but pass a short distance between the muscular 

 and nervous coats, which at that part are rather thicker 

 than elsewhere, and finally open into its cavity by an 

 oblique mouth. This peculiarity of structure prevents 

 the urine from regurgitating into the ureters from the 

 bladder. (A) 



495. The urinary bladder,^ varying in shape accord- 

 ing to age and sex, is generally capable, in the adult, 

 of containing about two pounds of urine. Its fundus, 

 which in the foetus terminates in the urachus, is covered 

 posteriorly by the peritonaeum. The other coats cor- 

 respond with those of the stomach. 



The muscular consists of interrupted bands of fleshy 

 fibres, variously decussated, and surrounding the blad- 

 der.^: These are usually called the detrusor urinae : 

 the fibres which imperfectly surround the neck and are 

 inconstant in origin and figure, have received the appel- 

 lation of sphincter. 



The nervous chiefly imparts tone to this membranous 

 viscus. 



The interior, abounding in cribriform follicles, is 

 lined with mucus, principally about the cervix. 



496. The urine conveyed to the bladder, gradually 

 becomes unpleasant by its quantity, and urges us to 



* See Nuck, Adenographia. fig. 32, 34, 35. Leop. M. Ant. Caldani, Saggi 

 dell' Accad. di Padova. T. ii. p. 2. 



f* Duverncy, CEuvres anatomiqwes. Vol. ii, tab. i. iv. 



J Santorini's posthumous tables, xv. 



Flor. Caldani, Opw. anat. Patav. 1805, 4to, p. 5. 



