Yolk sac

Definition

The yolk sac is an early embryonic structure that provides nutrients to the developing embryo and plays a critical role in the formation of the digestive system and blood cells. It is among the first structures to develop from the blastocyst in mammalian development.

Related terms

Embryo: An organism in its early stages of development, particularly before it has reached a distinct stage of development in species that undergo significant change.

Blastocyst: A structure formed in the early development of mammals, consisting of a spherical layer of cells filled with fluid, from which the embryo begins to develop.

Hematopoiesis: The process by which new blood cells are produced, starting from stem cells in bone marrow and during early development, also in structures like the yolk sac