Yolk Sac

Description: The yolk sac is an extraembryonic membrane that plays a crucial role in providing nutrition to the developing embryo in various vertebrates, including mammals, birds, and reptiles. This structure forms from the endoderm and mesoderm during the early stages of embryonic development. Its primary function is to supply nutrients to the embryo before the placenta is established in mammals or before the embryo begins to feed independently in reptiles and birds. The yolk sac contains a substance rich in proteins and lipids, which are essential for the initial growth and development of the embryo. Additionally, it serves as a site for gas and waste exchange, contributing to the embryo’s homeostasis. As development progresses, the yolk sac may be reabsorbed or transformed into other structures, depending on the species. Its study is fundamental in developmental biology, as it provides insights into the mechanisms of nutrition and embryonic development, as well as the evolution of reproductive strategies in vertebrates.

• Rating:
• 
• 
• 
• 
• 
• 3.3
• (6)