What roles do the yolk and albumen play in the development of a fertilized egg?

In a fertilized egg, the yolk and albumen serve distinct and essential functions to support the development of the embryo:

• Yolk: This component acts as the primary source of nutrition for the developing embryo. It contains a complex mixture of proteins, lipids, cholesterol, and fats that are essential for growth. As the embryo develops, a yolk sac forms, and a network of blood vessels transports these nutrients to the embryo.123
• Albumen: Often referred to as the egg white, the albumen provides the water necessary for embryonic development. Additionally, its various layers act as a protective cushion, shielding the embryo from jarring movements or physical shocks.1

Furthermore, structures known as the chalazae help maintain the proper orientation of the embryo within the egg, ensuring it remains stable during its development.1