Mesonephros in a chicken embryo (40X)

Chicken embryo 5 weeks gestation. Image copyright: University of Oslo, CC BY-NC-ND 4.0. (Tissue stain: H+E).

This is a section through a chicken embryo at a stage corresponding to about 5 weeks gestation in a human. The section is cut in (approximately) the frontal plane but the folding of the embryo complicates the interpretation of the structures in three dimensions. The cavity in the middle is the intraembryonic coelom. This space will give rise to the thoracic and abdominal cavities.

Published May 6th 2019, updated October 17th 2021.