what is the layers of mammalian eggs

Answer 1

Mammalian eggs, also known as ova, have several layers that protect and nourish the developing embryo. These layers include:

1. Zona pellucida: This is the outermost layer of the egg. It is a thick glycoprotein-rich layer that surrounds the entire egg and helps protect it from external environment and prevents fertilization by more than one sperm.

2. Corona radiata: This layer is located just outside the zona pellucida. It is composed of a layer of follicular cells that surround the egg and provide additional protection.

3. Vitelline membrane: This proteinaceous layer lies beneath the zona pellucida and is a boundary layer between the outer layers and the cytoplasm of the egg.

4. Cytoplasm: The cytoplasm of the egg contains a variety of organelles such as mitochondria, ribosomes, endoplasmic reticulum, and various other structures necessary for the development of the embryo.

These layers together provide the necessary protection and nourishment for the mammalian egg during fertilization and early embryonic development.