The Origin and Development of Smooth Muscle and Contractility in the Ductus Epididymidis of the Rat
The contractile activity of smooth muscles of the epididymal duct has long been overlooked in discussions relating to functional aspects of the epididymis and the problem of sperm transport in the male. Benoit (1926) described the occurrence of smooth muscle fibers, circularly arranged, surrounding the efferent ductuli and ductus epididymidis. Young and co-workers (1929–1931) emphasized that currents produced by vibrant cilia of the ductuli efferentes, the continued production of sperm in the testis, and the pressure of fluids transferred across the germinal epithelium to the lumina of the efferent duct system were responsible primarily for the movement of spermatozoa through the epididymis to their storage place in the caudal end of this organ prior to emmission. Simeone (1933) described contractile movements in the excised epididymis of the guinea-pig, and, although she discussed the probable occurrence also of peristaltic action, she concluded that the activity was mainly of a segmentationlike character.