There are large and small folds in the mucosa, some of which create grooves that end blindly. There is also a multilayered vascular plexus in the wall that resembles erectile tissue and could serve to reduce the lumen. The wall of the junction and lower isthmus contains a thick muscular layer that could further compress the lumen, the action being accentuated by muscle in the infundibulocomual ligament that could act to increase the flexure of the sigmoidal lumen. The narrowness of the lumen is especially apparent in frozen sections, because tissue does not shrink as it does during preparation of paraffin-embedded sections. Thus, sperm entrapment in the reservoir may be due to a number of factors that enhance the trapping effectiveness of adhesive molecules on the epithelium, particularly by increasing contact of sperm with the mucosal surface. buy prednisone
Little is known about sperm release from the epithelium for fertilization. Changes in the hormonal state of oviductal epithelium related to impending ovulation do not appear to affect the number of binding sites for sperm; however, the state of the sperm does affect binding.