Question

What happens in cortical reaction?

Answer 1

Cortical reaction:

The cortical response is a calcium-dependent extracellular process in which components of secretory granules are released into the perivitelline space shortly after fertilization, preventing polyspermic fertilization.

Human fertilization occurs in multiple stages that involve both chemical and physical activities.

1. Acrosomal Reaction
2. Cortical Reaction
3. Sperm Entry
4. Karyogamy
5. Activation of Eggs

The cortical reaction happens:

1. To prevent polyspermy, the cortical reaction occurs after a sperm has successfully invaded an egg.
2. Cortical granules in the cytoplasm of the egg release enzymes (through exocytosis) into the zona pellucida (jelly coat).
3. These enzymes degrade sperm binding sites while also thickening and hardening the jelly coat's glycoprotein matrix.
4. This stops other sperm from penetrating the egg (polyspermy), guaranteeing that the zygote generated is diploid.