Scanning electron microscopy of the infundibulum, ampulla, and eggs of mice.

The objective of the study reported here was to use scanning electron microscopy (SEM) to discover and describe the details of three-dimensional profiles and the natural (not surgically disturbed) topography/location of the infundibulum in the mouse. It will help new investigators to more quickly identify the infundibulum for successful transfer of microinjected eggs through a small opening into the oviduct/ampulla of pseudopregnant female mice for producing transgenic mice. Results of the study also illustrate the geographic orientation and natural topographic features of the ovary, infundibulum, ampulla, oviduct, and uterus. The presence of cilia on the surface of the crown foldings in the longitudinal section of the infundibular head stained with 1% toluidine blue provided direct evidence that evagination of the internal cilia of the infundibulum/oviduct results in formation of the infundibular crown. The new observation of the narrowing region of the infundibular head after surgical removal of the crown also suggests that formation of the infundibular crown may have resulted from the "evagination process" of internal cilia of the infundibulum/oviduct surface. The results also provide new evidence that the crown, terminal opening, and appearance of the left and the right infundibula of the same mouse differ.