Placentation in mammals: definitive placenta, yolk sac and paraplacenta

An overview is given of variations in placentation with particular focus on yolk sac, paraplacenta and other structures important to histotrophic nutrition. The placenta proper varies in general shape, internal structure and the number of tissues in the interhemal barrier. Yolk sac membranes persist to term in insectivores, colugos, rodents and lagomorphs. In the latter two orders they are of known importance for maternal-fetal transfer of antibodies, vitamins, lipids and proteins. The detached yolk sac of bats is also active throughout gestation.

Source: Theriogenology - April 20, 2016 Category: Genetics & Stem Cells Authors: A.M. Carter, A.C. Enders Source Type: research