Vasculature of bovine placentas studied by scanning electron microscopy of corrosion casts.

Corrosion casts, obtained after injection of Tensol or Mercox, from 10 placentas of Holstein breed cows, were studied. The investigation was performed in fetal cotyledons, which are attached to uterine caruncles to form units, called placentons. Arteries and veins form, together, vascular cylinders, with the venous half cartridge partially surrounding the arterial one. The morphological differences between arterioles and venules concern the type of distribution, branching, surface (nuclei, oblique folds, anular narrowings).