Abstract

PIP: After a brief historical review of studies on the Fallopian tubes, their functional anatomy is considered with regard to cilia; secretory cells, the mucosa, musculature, innervation, and vasculature. Muscula activity is treated in relation to the transport of gametes and embryos, and secretory activity in relation to the maturation of gametes and development of embryos. The isthmus may function critically in regulating sperm numbers available for fertilization while simultaneously acting as a temporary sperm reservoir, and entry of eggs into the ampulla may stimulate release and capacitation of spermatozoa from the lower regions of the tube. Because of the rapidity of egg transport to the ampullary-isthmic junction, the latter is the site of fertilization in most mammals though apparently this is untrue in women. Subsequent passage of the embryo along the isthmus is under the influence of gonadal steroids, and appears to be regulated locally by an interplay of alpha- and beta-adrenergic receptor activity in the myosalpinx and by tissue prostaglandins, as well as by the extent of edema in the mucosa. The possibility that embryonic secretion of hormones contributes to this control should be recognized as should the role of steroid-induced anomalies of egg transport in the etiology of tubal pregnancies. Tubal fluid is no ed to be composed of serum transudate and specific secretion containing some unique protein(s), and is regulated by the prevailing balance of ovarian hormones, but a trophic influence of the embryo is again considered. Finally, reference is made to clinical problems in the light of evidence obtained from experimental animals, and it is reasoned that attempts to regulate human fertility by modified tubal function could prove to be unsatisfactory.