THE URINARY APPARATUS. 541 



remarkable for their number of fat-granules. The pancreatic duct 

 is lined by a mucous membrane, an offset from that of the duode- 

 num, with a simple conoidal epithelium; and presenting many 

 small racemose glands probably analogous to the mucous glands 

 of the bile-ducts. (Kolliker.) 



The bloodvessels are distributed precisely as those of the parotid 

 gland ; while the lymphatics are more numerous. The nerves only 

 accompany the vessels, and rise from the great sympathetic. 



The secretion of the pancreas is of the greatest importance to 

 the function of digestion, as has been explained on page 213. 



CHAPTER XIV. 



THE URINARY APPARATUS. 



THE urinary organs are the kidneys, the ureters, the bladder, and 

 the urethra. The mucous membrane lining the last three, forms 

 the urinary passages ; while that of the uriniferous tubes of the kid- 

 neys is the seat of the secretion itself. The urinary passages will 

 be first described, and then the substance of the kidney. 



1. The urethra of the male will be described with the sexual organs 

 (p. 550). That of the female has a reddish mucous membrane, with 

 a compound scaly epithelium, and a quite vascular corium. The 

 latter also contains, especially near the bladder, a certain number 

 of racemose mucous glands (Littre's glands, Fig. 380), like those of 

 the bladder, except that they are larger (sometimes even ^ of an 

 inch in diameter), and more closely placed. It has a tunic of lon- 

 gitudinal and transverse smooth muscular fibres, intermixed with 

 areolar tissue; and outside of this^ the musculus urethra Jis (Kolliker), 

 consisting principally of transverse fibres. In the submucous areo- 

 lar tissue is a plexus of veins, which has been incorrectly described 

 as a corpus spongiosum. 



2. The bladder has, externally to its lining mucous membrane, 

 two layers of smooth muscular fibres: 1, an internal, consisting of 

 oblique and transverse fasciculi, incompletely covering the mucous 

 memlyane from their reticular arrangement, but constituting a 

 strong circular layer at the neck of the bladder (the sphincter ve- 



