THE UROGENITAL SYSTEM 



313 



ous tubules. Diminution in the activity of the tubules occurs 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 trails 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 gubernaculum. 



SPERMATIC- 

 CORD. 



PUBIC 



SYMPHYSIS 



CORPUS 



CAVERNOSUM 



PENIS. 



urogen ital 

 "Diaphragm, 

 •bulbourethral 



GLAND. 

 BULBUS. 



--/-RECTUM 

 EXTERNAL 

 -SPHINCTER 

 MUSCLE. 



•ANUS. 



Fig. 278. — The male urogenital system. 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.) 



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

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

 in length, which together with the efferent ducts forms the head of the 

 epididymis. The ductus epididymidis is the beginning of the ductus 

 deferens and, like it, Hned with ciliated columnar epitheHum. The 

 ciUa beat towards the urethra and carry the spermatozoa to the seminal 

 vesicles where they may be temporarily stored. Layers of circular and 

 longitudinal muscles are present in the wall of the duct. At the lower 

 end of the testis the ductus loops back along the tail or Cauda of the 

 epididymis, and then leaves the epididymis to join the spermatic cord. 

 As a component of the spermatic cord it passes through the inguinal canal. 

 Entering the body cavity, the ductus leaves the spermatic cord and 



