What is the Difference Between Zona Pellucida and Corona Radiata?

The zona pellucida and corona radiata are two layers that surround the plasma membrane of oocytes. They play crucial roles in the fertilization process and protect the developing embryo. Here are the key differences between the two:

Zona Pellucida:

1. Non-cellular in nature.
2. Composed of glycoproteins.
3. Present just around the plasma membrane of the oocyte.
4. Contains sperm-binding proteins for easy adhesion of sperm cells to the plasma membrane and prevents polyspermy.
5. Shed off as the embryo reaches the uterine wall for implantation.

Corona Radiata:

1. Multicellular in nature.
2. Composed of proteins, carbohydrates, and hyaluronic acid.
3. Surrounds the zona pellucida layer.
4. Initiates the acrosomal reaction of sperm and prevents polyspermy.
5. Protects and supplies vital proteins to the ovum.

In summary, the zona pellucida is a non-cellular glycoprotein layer that surrounds the oocyte's plasma membrane, while the corona radiata is a multicellular layer composed of proteins, carbohydrates, and hyaluronic acid that surrounds the zona pellucida. Both layers play essential roles in fertilization and protecting the developing embryo.

Comparative Table: Zona Pellucida vs Corona Radiata

The zona pellucida and corona radiata are two protective layers that surround a mature ovum. Here are the key differences between them:

The zona pellucida is a non-cellular, thick glycoprotein coating that surrounds the plasma membrane of the oocyte. It plays a crucial role in fertilization by preventing polyspermy and facilitating the adhesion of sperm cells to the plasma membrane. On the other hand, the corona radiata is a multicellular layer composed of proteins, carbohydrates, and hyaluronic acid, formed by the adhesion of follicle cells. It protects the ovum and supplies vital proteins to it.