714 



SPERM, OVA, AND PREGNANCY 



TABLE 13.1 



Distribution of spermatozoa in male 



genital tract of ram 

 (From M. C. Chang, J. Agric. Sc, 

 35, 243-246, 1945.) 



C. THE FUNCTIONAL MICROANATOMY 

 OF THE EPIDIDYMIS 



The epididymis has received considerable 

 attention from microscopists bent on the 

 elucidation of the role this part of the duct 

 system plays in the reproductive physiology 

 of the male. A number of recent papers have 

 contributed to our understanding of the 

 segmental organization of the epididymis, 

 the cytochemistry of the mucosa, and the 

 response of the duct to steroid influences. 

 For many histochemical details, and histori- 

 cal surveys of much of the earlier literature, 

 the following papers should be consulted: 

 Reid and Cleland (1957), Cavazos (1958), 

 Maneely (1958, 1959), and Reid (1958, 

 1959) concerning the rat; Ladman and 

 Young (1958) on the guinea pig; Nicander 

 (1957) for the rabbit; and Nicander (1958) 

 concerning the stallion, ram, and bull. Al- 

 though exquisite in detail and extensive in 

 scope, these papers, with few exceptions, 

 have added little to the earlier contributions 

 concerning the function of the epididymis 

 vis-a-vis the physiology of the spermatozoa 

 within the lumen (c/. Young, 1933; Mason 

 and Shaver, 1952). With the cytochemical 

 background now available, however, and 

 the current interest in epididymal physiol- 

 ogy, the expectations to be derived from a 

 more functional approach should now be 

 fulfilled. 



Emphasis has again been placed on the 

 epididymal mucosa, and particularly on the 

 vacuolar and endoplasmic reticular system 

 as a site for the reabsorption of fluid (Ni- 

 cander, 1957; Reid and Cleland, 1957; Lad- 

 man and Young, 1958) , in contrast to its 



function as a secretory organ (Hammar, 

 1897; Henry, 1900; Benoit, 1926; Maneely, 

 1954; Goglia and Magh, 1957). The old 

 question as to the cause of increasing sperm 

 density has apparently been resolved re- 

 cently by ligation experiments in the rat 

 (Cleland, Jones and Reid, 1959) ; a spe- 

 cialized region of the epididymis absorbs 

 fluid from the lumen at the point where 

 sperm concentration suddenly increases. 

 Virtually nothing is known about the trans- 

 port of substances, other than water and 

 possibly inorganic ions, across the mucosal 

 boundary, despite the elaborate cytochemi- 

 cal reports, which include data for acid and 

 alkaline phosphatase activitv (Bern, 1949a, 

 b, 1951; Wislocki, 1949; Maneely, 1955, 

 1958; Montagna, 1955; Allen and Slater, 

 1957, 1958; Cavazos, 1958; Allen and 

 Hunter, 1960), metachromatic substances 

 (Cavazos, 1958), glycogen (Leblond, 1950; 

 Montagna, 1955; Nicander, 1957, 1958; Ca- 

 vazos, 1958; Maneely, 1958), lipids (Chris- 

 tie, 1955; ]\Iontagna, 1955; Cavazos and 

 Melampy, 1956; Nicander, 1957, 1958), gly- 

 coprotein (Cavazos, 1958) , and nucleic acids 

 (Nicander, 1957, 1958; Cavazos, 1958). It 

 would be of interest to know how these cyto- 

 chemical characteristics vary, if indeed they 

 do, with sexual activity, on the one hand, 

 and, on the other hand, with certain func- 

 tional processes, such as the reabsorption 

 of fluid from the duct, the possible transfer 

 of tagged molecules across the limiting 

 membrane, the elaboration and secretion 

 of, for example, glycerylphosphorylcholine 

 present in the epididymis (Dawson and 

 Rowlands, 1959) , and the uptake of large 

 molecular moieties into the mucosa from the 

 lumen, as demonstrated with trypan blue, 

 pyrrhol blue, fuchsin, and India ink parti- 

 cles (von Mollendorf, 1920; Young, 1933; 

 Mason and Shaver, 1952; Shaver, 1954). 



Nicander's studies have the added merit 

 that cytochemical demonstrations are cor- 

 related with regional differentiation of the 

 epididymis; the duct is divided into 6 to 8 

 cytologically distinct segments. Such divi- 

 sion includes the efferent ducts as part of 

 the epididymis, whether they appear to be 

 nested within a depression of the testis, as 

 in the guinea pig, or quite external to it as 

 in the stallion, ram, bull, and rabbit. All 



