When an oocyte is developing in an ovary, it is encapsulated in a spherical collection of cells known as an ovarian follicle.
This layer is responsible for the peristaltic action of the Fallopian tubes. There are two types of cells within the simple columnar epithelium of the Fallopian tube (oviduct).
Tubal fluid flows against the action of the ciliae, that is toward the fimbrial end.
In view of longitudinal variation in histological features of tube, the isthmus has thick muscular coat and simple mucosal folds; whereas ampulla has complex mucosal folds.
The secondary oocyte is caught by the fimbriated end and travels to the ampulla of the uterine tube where typically the sperm are met and fertilization occurs; meiosis II is promptly completed.
The fertilized ovum, now a zygote, travels towards the uterus aided by activity of tubal cilia and activity of the tubal muscle.