ACTIVITIES OF THE MALE REPRODUCTIVE SYSTEM 



29 



MORPHOLOGICAL 

 MATURATION 

 THE TESTES 



Fig. 16 



MORPHOLOGICAL 

 AND PHYSIOLOGICAL 

 MATURATION IN THE 

 TESTES - NO 



CONVOLUTED EPIOIDYMAL 

 DUCTS . 



Fig. 17 



PHYSIOLOGICAL 

 MATURATION AND 

 SPERM STORAGE 

 IN HIGHLY DEVELOPED 

 EPIDIDYMAL DUCTS 



Fig. 16. Effects of the male sex hormone upon the functional development of the 

 accessory reproductive structures of the male rat. (After Turner: General Endocrinology, 

 Philadelphia, Saunders, p. 324.) (A) Normal male rat condition produced by injection 

 of crystalline male sex hormone for 20 days into castrate before autopsy. (B) Castrated 

 male litter mate of (A) receiving no replacement therapy. 



Fig. 17. Diagrammatic drawings of the two types of testicular-reproductive relation- 

 ships occurring in the vertebrate group. (A) Simplified type of reproductive duct con- 

 nected with the testis by means of efferent ductules. The duct-testis relationship of many 

 teleost fishes is similar to this but does not possess the efferent ductules, the sinus-like 

 reproductive duct being attached directly to the testis. Sperm cells (spermatozoa) are 

 matured and stored within the testis. This type of relationship generally is found where 

 fertilization is external or where sperm are discharged all at once during a short repro- 

 ductive period. (B) More complicated variety of reproductive duct, connected with the 

 testis by means of efferent ducts, but possessing an anterior twisted portion, the epididymal 

 duct in which the sperm are stored and physiologically matured. This type of duct 

 generally is found in those vertebrates which utilize internal fertilization and where 

 sperm are discharged over a short or extended reproductive period. 



ticular maturation is characteristic of many of the lower vertebrates possessing 

 simple reproductive ducts. 



b. The Epididymis as a Sperm-ripening Structure 



On the other hand, in those forms which possess an anterior convoluted 

 epididymal portion of the reproductive duct, the journey of the sperm through 

 this portion of the duct appears to be necessary in order that fertilizable sperm 

 may be produced. In mammals it has been shown that the epididymal journey 

 somehow conditions the physiological ripening of the sperm. Sperm taken 



