And we have these cortical granules, these vesicles that contain special enzymes that help initiate the process known as the cortical reaction. And we'll discuss what that is in just a moment. Now, surrounding the plasma membrane of the egg cell, we have a layer of glycoproteins known as the zona pellucida. And the first contact that takes place between the sperm cell and our exile takes place at the zona pellucida. So when the sperm cell contacts the egg, it interacts first with this layer of glycoproteins known as the zona pellucida. And what happens is the acrosome structure found on the apex, on the tip of that sperm cell releases these digestive enzymes that begin digesting a hole in the zona pellucida.