824 



SPERM, OVA, AND PREGNANCY 



the isthmus of this animal. Alden (1942b) 

 and Deane (1952) were unable to observe 

 cyclic variations in the histologic or histo- 

 chemical picture of the oviducts of the rat. 

 In the mouse the primary cyclic alteration 

 of the epithelium is restricted to a slight but 

 significant variation in the height of the 

 ciliated cells ('Espinasse, 1935). In the 

 sheep the majority of the secretory cells are 

 confined to the ampulla, few being found 

 in the isthmus (Hadek, 1953). Hadek de- 

 scribes a significant increase of secretory 

 products in the lumen of the oviduct during 

 estrus and early in the metestrum. 



Studies of electron micrographs of ultra- 

 thin sections of oviducts of the mouse, man 

 (Fawcett and Porter, 1954), rabbit (Borell, 

 Nilsson, Wersall and Westman, 1956; Nils- 

 son, 1957), and rat (Odor, 1953; Nilsson, 

 1957, 1959) have demonstrated the similar- 

 ity of the ciliary apparatus of epithelial cells 

 in the various species. Of special interest was 

 the presence of tiny, filiform projections on 

 certain of the cells interspersed among the 

 ciliated cells (Fig. 14.9). Similar projections 

 are also found on the luminal surface of 



what are probably the secretory cells. These 

 processes do not have the longitudinal fibrils 

 nor basal corpuscles that are essential com- 

 ponents of cilia. A comparative study of the 

 fine structure of the mammalian oviducts 

 at carefully timed intervals and under dif- 

 ferent hormonal influences may lead to im- 

 portant observations of cyclic variations in 

 both the ciliated and secretory cells (Borell, 

 Nilsson and Westman, 1957). 



The histochemical characteristics of the 

 epithelium of the oviduct have been studied 

 particularly by Deane (1952) and Milio 

 (1960) in the rat, Hadek (1955) in the 

 sheep, Fredricsson (1959b) in the rabbit, 

 Fawcett and Wislocki (1950) and Fredrics- 

 son (1959a) in man. In the rat alkaline 

 phosphatases occur on the ciliated borders 

 of the cells of the isthmus, which suggests 

 that this material has a role in the trans- 

 fer of phosphorylated compounds. The rat 

 differs from many other species in that gly- 

 cogen could not be demonstrated in the epi- 

 thelium of the oviduct at any time of the 

 cycle. Quantities of esterase were present in 

 the cells of all regions but only the cells of 



tr/s.;^y ,Mv, ^ .-V^ 



Fig. 14.9. Electron microgiaph of a thin section of the oviduct of the rat. Note nonciliated 

 cell with microvilli wedged between ciliated cells. NN, nucleus of nonciliated cell ; NC, nu- 

 cleus of ciliated cell; BB, basal bodies; C, cilia; MV, microvilli. (Courtesy of Dr. L. Odor.) 



