Why does fertilization of an oocyte typically result in blocking polyspermy, preventing multiple sperm from entering?

💡 Explanation

Fertilization causes a cortical reaction, where cortical granules release enzymes. This alters the zona pellucida, preventing other sperm from binding because the receptors are changed. Therefore, polyspermy is blocked, rather than simply destroying sperm or weakening the zona without changing its structure.

• In type 2 diabetes, why does increasing circulating insulin not always effectively lower blood glucose levels, even with functioning pancreatic beta cells?
• Why does drug dosage need adjustment for patients with impaired renal function?
• Which outcome is caused by the increased resistance across demyelinated axons?
• In the context of drug addiction, what causes escalating drug cravings despite diminished euphoric effects with repeated use?
• Which failure mode becomes likely when arterial stiffness increases in a patient with hypertension?
• What causes decreased blood pressure when peripheral blood vessels dilate during exercise?