This image shows a Japanese quail (Coturnix japonica) embryo inside its egg. The image was captured using MRI and 3D rendered to show various layers of information about the external egg structure and the developing embryo inside. This embryo is 6-days-old and about 14 mm in length at this stage.
Avian embryos are important experimental models for investigating embryonic development and in particular the processes that control the laying down of the body plan and organogenesis. Their importance is due, at least in part, to the fact that they are encased within an egg which provides nearly all the components necessary for development allowing scientists to study the development of the embryo outside the body of the mother.
In addition to the embryo, the egg is composed of extra-embryonic and non-embryonic components. The extra-embryonic components (e.g. yolk sac, allantois and amnion) are temporary structures participating in fundamental metabolic processes such as respiration, nutrition and excretion. The non-embryonic components of the egg (e.g. yolk, albumen and shell) provide nutrients and also physical and microbial protection for the growing embryo.
