Zoology - Human Reproduction Question with Solution | TestHub

Block to polyspermy is an important step which takes place in humans (even in sea urchins) during fertilization. This is done by two events. Fast block to polyspermy takes place because of opening of sodium channels that cause the oocyte membrane to get depolarized. There is slow block to polyspermy too. This takes place due to cortical and zona reactions. These two types of block to polyspermy ensures that only one sperm can fertilise the ovum.