PROSTATE 



345 



PROSTATE. 



The prostate is a group of branched tubulo- alveolar glands, imbedded 

 in a mass of muscular tissue, which stands before the outlet of the bladder. 

 The smooth muscle of the adult prostate forms a quarter of the bulk 

 of the organ, and together with an elastic connective tissue, it unites the 

 numerous glands in a compact mass. The development of these glands 

 up to the time of birth, has been studied by Lowsley (Amer. Journ. Anat., 

 1912, vol. 13, pp. 299-349). He finds that the prostate includes from 

 fifty-three to seventy-four separate glands (the average number being 

 sixty-three) which are grouped in five 

 lobes. The middle lobe consists of nine 

 to ten large glands growing out from the 

 dorsal side of the urethra, between the 

 bladder and the openings of the ejacu- 

 latory ducts. The glands of the posterior 

 lobe grow out from the dorsal wall of the 

 urethra below the ejaculatory ducts; 

 those of the right and left lobes develop 

 from the sides of the prostatic urethra; 

 and those of the anterior lobe proceed 

 from its ventral surface. The anterior 

 lobe is well enveloped in young embryos, 

 but it "shrinks into insignificance at the 

 twenty-second week." It may persist in 

 the adult, but the great mass of the pros- 

 tatic glands is at the sides and back of 

 the prostatic urethra. The number of 

 glands apparently becomes reduced. In 

 the adult it is said to be from thirty to 

 fifty. 



The glandular epithelium is simple 

 and either cuboidal or columnar. It may appear stratified as it passes 

 over the folds in the walls of the tubules. Near the outlet of the larger 

 ducts the epithelium is like that of the bladder and prostatic urethra. In 

 the prostatic alveoli, of older persons especially, round or oval colloid 

 masses from 0.3 to i.o mm. in diameter occur; as seen in sections (Fig. 

 348) they exhibit concentric layers. Their reactions on treatment with 

 iodine solutions suggest amyloid. These concretions are probably de- 

 posited around fragments of cells. Octahedral crystals also occur in the 

 prostatic secretion, which is a thin milky emulsion, faintly acid; it has a 

 characteristic odor, whereas the other constituents of the seminal fluid are 

 said to be odorless. 



FIG. 347. FROM A SECTION OF THE PROS- 

 TATE OF A MAN TWENTY-THREE YEARS 

 OLD. X so. 



