The three-dimensional architecture of the myosalpinx in the cow as revealed by scanning electron microscopy

The three-dimensional architecture of the myosalpinx in the cow has been investigated by means of scanning electron microscopy after removal of interstitial connective tissue with NaOH digestion. In the extramural portion of the tubo-uterine junction, in the isthmus and ampulla, the myosalpinx is made up of oblique bundles of variable orientation and length, which are loosely distributed in the tubo-uterine junction and densely packed in both isthmus and ampulla. These bundles intersect and merge into the surrounding musculature. Our observations demonstrate how myosalpinx consists mainly of bundles of muscular fibers independent one of another, which show a multiple spatial arrangement and form a complex network. Such a muscular architecture is likely more suitable for stirring rather than pushing the embryos and gametes through the tube.