What structure contains sperm receptors specific for human sperm?

The correct answer is the zona pellucida. This is a glycoprotein layer surrounding the plasma membrane of the oocyte (egg cell) that plays a crucial role in fertilization. Specifically, the zona pellucida contains sperm receptors that are essential for the binding of sperm to the oocyte. These receptors are highly specific to human sperm, ensuring that fertilization occurs only when compatible sperm interact with the egg. Once a sperm successfully binds to the zona pellucida, it triggers a series of biochemical changes that facilitate the sperm's entry into the egg.

In contrast, the corona radiata consists of a layer of cells that surround the oocyte and serve to provide nutrients and support, but it does not have specific receptors for sperm. The inner cell mass is part of the blastocyst and contributes to the formation of the embryo after fertilization, so it is not involved in the initial stages of sperm-egg interaction. The cumulus oophorus is a cluster of cells that support the oocyte and aid in its ovulation process, but like the corona radiata, it does not contain specific receptors for sperm. Understanding these distinctions underscores the unique role the zona pellucida plays in the process of fertilization.