THE UROGENITAL SYSTEM 



427 



tion of cells beginning in the basal layers. During this process a 

 reductional or maturation division takes place previous to the meta- 

 morphosis of the cells into mature spermatozoa. All transitional stages 

 in the conversion of epithelial cells into spermatozoa may be seen in a 

 cross section of the seminiferous tubules. The Sertoli cells which occur 

 among the germ-cells are usually assumed to have a nutritive function. 

 As the spermatozoa lose connexion with the epithelium, they pass into 

 the lumen of the tubules, and thus find their way to the epididymis, 

 in which they may be retained for some time. They are contained in 

 a mucous alkaline liquid, also secreted by the epithelium of the seminifer- 



SPERMATIC- 

 CORD. 



PUBIC 

 SYMPHYSIS 

 CORPUS 

 CAVERNOSUM 

 PENIS. 



CORPUS- 

 CAVERNOSUM 

 URETHRAE 



UROGEN ITAL 

 "DIAPHRAGM. 

 •BULBOURETHRAL 

 GLAND. 

 BULBUS. 



•RECTUM- 

 EXTERNAL 

 -SPHINCTER 

 MUSCLE. 

 -ANUS. 



Fig. 352. — The urogenital system — male. The glandular complications of the male 

 urogenital system appear to be in part an adaptation to the double function of the 

 urethra — excretory and reproductive. The alkaline secretions of the glands serve to 

 neutralize the acidity of the urethra caused by the acid urine. (Sobotta.) 



ous tubules. Diminution in the activity of the tubules is seen in old age, 

 and may begin as early as thirty-five years. 



The interstitial tissue between the seminiferous tubules is believed to 

 have an endocrinal function and to influence the development of secondary 

 sex traits and the vigor of the individual. 



Also associated with the testes are certain rudimentary organs, 

 ductuli aberrantes, paradidymis, hydatid of Morgagni, the significance 

 of which will be better understood after the description of their develop- 

 ment. Each testis is attached to the scrotum by a connective tissue cord, 

 the gubemaculum. 



Ductus Deferens. By the efferent ducts of the testis, sperm is carried 

 to the ductus epididymidis, a much convoluted tube twenty or more feet 



