BIOLOGY OF SPERMATOZOA 



731 



ret, for example, which also normally ovulate 

 only when stimulated by copulation, might 

 be instructive. 



The time for sperm migration in fowl is of 

 the same order of magnitude as that in most 

 mammals (Mimura, 1941). Fowl sperm, 

 labeled with inorganic P-^-, were recovered 

 from the infundibulum within an hour after 

 insemination; the number found depended 

 on the site of administration, i.e., intravagi- 

 nal or intrauterine (Allen and Grigg, 1957). 

 Killed sperm also reached the infundibulum 

 when placed in the uterus, but not when in- 

 troduced intravaginally. 



The study of seminal components, other 

 than sperm, indicates that tubal transport 

 must involve a muscular mechanism. In both 

 the sow and the mare, certain natural semi- 

 nal constituents, e.g., fructose, citric acid, 

 and crgothioneine, are found in the uterine 

 horns within an hour after mating (Mann, 

 Polge and Rowson, 1955). Gunn and Gould 

 ( 1958 ) produced a Zn*'^-labeled component 

 of prostatic fluid in rats which served as a 

 marker for tubal transport. In animals killed 

 at intervals between 0.5 and 1.5 hours after 

 mating, a significant quantity of the isotope 

 had reached the uterotubal junction by 1 

 hour, and radioactive labeling was found 

 throughout tlie oviduct at 1.5 hours. 



B. MECHANISM OF TRANSPORT IN THE UTERUS 

 AND OVIDUCT 



The muscular contractility of the genital 

 tract has been implicated in the process of 

 sperm migration since the earliest studies 

 of mating behavior and insemination (see 

 Austin and Bishop, 1957). The normal ac- 

 tivity of the uterus and Fallopian tube is 



well known (Westman, 1926; Parker, 1931; 

 Reynolds, 1931, 1949). The contractions of 

 the tract are not, however, peristaltic waves 

 which might favor rapid, directed sperm 

 transport, but rather segmentation waves 

 which encourage dispersal from the source. 

 Indeed, what peristalsis can be observed in 

 the estrous oviduct (e.g., the rabbit) is di- 

 rected from the fimbriated toward the uter- 

 ine end (Reynolds, 1949j. 



Both mechanical and psychic factors in- 

 fluence the contractility of the genital tract 

 and api^ear to augment sperm migration. In 

 the ral)bit (Heape, 1898; Krehbiel and Car- 

 stens, 1939), and probably in many other 

 animals, stimulation of the external geni- 

 talia increases uterine activity. The mating 

 response also enhances uterine action in the 

 mare (Millar, 1952) and cow (VanDemark 

 and Hays, 1952). According to VanDemark 

 and Hays (1952) , the mere sight of the bull 

 is sufficient to induce strong uterine contrac- 

 tions in the estrous and postestrous heifer 

 (Fig. 13.7). The activity of the Fallopian 

 tube of the rabbit also appears to be stimu- 

 lated by the presence of a suitable buck 

 (Westman, 1926). 



In the oviducts of rabbits, Parker (1931) 

 emphasized both the segmentation contrac- 

 tions and the local ab- and adovarian ciliary 

 currents in accounting for dispersal of sperm, 

 once they pass the uterotubal junction. In a 

 recent series of interesting experiments, how- 

 ever. Black and Asdell (1958) tended to 

 minimize ciliary activity, which is generally 

 directed toward the uterus, and to attribute 

 sperm distribution in the rabbit oviduct to 

 the segmentation process brought about by 

 the circular musculature of the tube. Tubal 



MINUTES 



Fig. 13.7. Uterine responses in an estrous cow stimulated by various mating activities: A, 

 bull brought within sight of cow ; B, bull allowed to nuzzle vulva ; C, bull mounts but does 

 not copulate; D, bull copulates; E, bull ejaculates. (From N. L. VanDemark and R. L. Havs, 

 Am. J. Physiol., 170, 518-521, 1952.) 



