282 



HISTOLOGY. 



ually become elongated and it changes to the simple or few layered col- 

 umnar epithelium of the cavernous portion. In the dilatation of the ure- 

 thra near its distal end, the fossa navicularis, the epithelium becomes 

 stratified with its outer cells squamous; the underlying papillae of the 

 tunica propria become prominent, and the whole is the beginning of the 

 gradual transition from mucous membrane to skin. 



Glands. Small groups of mucous cells are scattered along the urethra 

 and in the cavernous part, especially on the upper wall, they form pockets 

 called urethral glands [of Littrej. Often these pockets are on the sides 



Connective tissue. 



Epithelium 



Red corpuscles in a 

 blood vessel. 



Smooth 

 muscle fibers. 



FIG. 321. FROM A SECTION OP THE PROSTATE OF A MAN TWENTY-THREE YEARS OLD. X 360. 

 The epithelium is cut obliquely at Jt, and has artificially separated from the connective tissue at XT. 



of epithelial pits so that the glands are branched. Non-glandular pits 

 also occur, known as urethral lacunae, and the " paraurethral ducts" near 

 the external orifice are large lacunae of various sorts. 



The two principal glands empty by irregularly dilated ducts, an inch 

 and a half long, into the beginning of the cavernous urethra. The bodies 

 of these bulbourethral glands are found one on either side of the mem- 

 branous urethra, in close relation with striated and smooth muscle fibers. 

 The end pieces, which are partly alveolar and partly tubular, anastomose. 

 They consist of mucous cells, with intercellular secretory capillaries, and 

 produce a clear, glairy mucus, discharged during sexual excitement. The 



