OBSERVATIONS ON THE TRANSPORT OF TUBAL OVA1

Abstract

Under proper lighting conditions, ova can be seen inside the fallopian tubes of albino mice. Direct observations show that peristalsis is responsible for the transportation of the eggs from the ampulla to the uterus. Cilia, however, may play an important role in getting the eggs from the periovarial sac to the ampulla. Although eggs were never seen to descend into the ampulla, ciliary action in this region is sufficiently strong to rotate, en masse, several eggs with their cumulus cells. This action is apparently only temporary, ceasing shortly after the eggs reach the ampulla. The ampullar walls are quiet until after fertilization, when gentle contractions roll the eggs about, a motion which apparently aids in separating them from their cumulus cells. Approx. 24 hrs. after ovulation, the cumulus cells having dropped away, the isthmian lumen is expanded sufficiently to allow the stronger ampullar contractions to force the eggs and some of the accompanying fluid into the first loop of the isthmus. This fluid seems to stimulate he muscle fibers. True peristalsis is confined largely to those loops in the immediate vicinity of the eggs, and appears to be a typical smooth-muscle response to increased bulk. The eggs are slowly advanced as each successive loop becomes sensitized and contractile. Transportation through the isthmus requires only about 24 hrs. The eggs are slowly advanced in the intramural region and may be found in the uterus at the end of another 24-hr. period.