242 



NORMAL HISTOLOGY. 



lobules occupied by glandular tissue. The involuntary muscle, embedded 

 within the capsule and the ramifications of the connective tissue framework, 

 surrounds the gland-substance as a superficial layer, from which a median 

 septum (about 2 mm. wide) extends ventro-dorsally and encloses the urethra 

 in an annular thickening. The interior of the prostate, therefore, is occu- 

 pied by a dense fibro-muscular core, or ' ' nucleus, ' ' in which the glandular 

 tissue is represented by the narrow prostatic ducts passing towards the 



Folds of 

 mucous membrane 



Urethral mucous 

 membrane 



Urethral crest 

 Prostatic 

 utricle 



Ejaculatory ducts 



FIG. 292. Section across prostatic urethra, above entrance of ejaculatory ducts, showing urethral crest 



with prostatic utricle. X 10. 



urethra. The muscle is not limited to the foregoing positions, but is found 

 between the divisions of the gland-tissue, the interalveolar septa consisting 

 in places largely of the variously disposed muscle-bundles. 



The glandular tissue embraces from 30-50 lobules drained by a 

 number ( 1 5-30) of excretory tubules, the prostatic ducts, that open into 

 the prostatic urethra in the groove on either side of the median elevation, the 

 colliculus. Beginning at their narrow orifices, the ducts pass outward into 

 the lobules, after a course of about i cm. dividing into tubules that repeatedly 

 branch and expand into the terminal alveoli. Throughout the greater part 

 of their course the wavy ducts are beset with succular and tubular diverticula, 

 simple or compound, that give the canals irregular lumina and constitute the 

 duct alveoli as distinguished from the terminal alveoli. The latter form a 

 series of irregularly branched tubular and saccular spaces lined with a single 

 or imperfect double layer of columnar epithelial cells, the secreting elements 

 of the gland. By communication the alveoli form in places networks of 

 spaces of variable form and size. The epithelium of the prostatic ducts and 

 their diverticula corresponds with that lining the terminal alveoli, the change 

 into the transitional variety found in the prostatic urethra not occurring until 

 very near the termination of the ducts. 



Peculiar concretions, known also as "prostatic calculi" or "amyloid 

 bodies," are almost constantly present within some of the alveoli of the adult 

 organ, especially in advanced life. These bodies (Fig. 294), round or oval in 

 outline and very variable in size (.2-1 mm. and more), usually exhibit a faint 



