Physiology: Morphology and ultrastructure of Fallopian tube epithelium at different stages of the menstrual cycle and menopause

The Fallopian tube has been reported to undergo cyclical changes. However, many studies of tubal ultrastructure have either examined one segment of the tube only or studied animal oviducts. The aim of this study was to document in detail the combined morphological and ultrastructural features of the epithelial lining along the length of the tube in women at different stages of the menstrual cycle. We report an increase in the proportion of ciliated cells along the tube, being highest in the fimbriae, but no substantial difference between the follicular and luteal phases of the menstrual cycle. In the late follicular phase, fragments of cytoplasmic and cellular material were seen in the isthmic lumen but not in the outer tubal segments. Similarly, surface domes and secretory granules were more prominent in the mid-tube and ampullary sections than in the fimbriae. This surface activity was followed by relative quiescence in the early/mid luteal phase with reversion to a more active surface but with little secretory activity in the late luteal phase. These findings along the Fallopian tube substantiate the concept of functional differentiation between the different segments and necessitate further studies to determine its clinical relevance