Definition - What does Capacitation mean?

Capacitation is the process by which the outer membrane of the head of the sperm is removed allowing the release of enzymes that enable the sperm to penetrate the outer layer of the egg for fertilization. Without the capacitation process, the sperm would be unable to penetrate the egg and fertilization could not occur. Supporting this process is important to maximize natural fertility as well as ensuring the ability of sperm to fertilize the egg in an in vitro fertilization procedure.

FertilitySmarts explains Capacitation

After ejaculation when the sperm enters the vagina, the acidic environment and secretions of the female reproductive tract prompt a chemical change in the sperm. This is part of the physiological maturation process the sperm must complete and only occurs once the sperm enters the female reproductive tract. These changes are essential to allow the sperm to penetrate the outer layer of the egg to successfully complete fertilization.

Two major changes in the sperm occur during capacitation. The first major change is a removal of the outer protein layer on the head of the sperm. Removing this layer releases enzymes that assist the sperm in breaking through the outer layer of the egg. The second change occurs in the tail of the sperm. During capacitation the tail of the sperm moves in a whipping motion with larger movements, increasing sperm motility and allowing the sperm to travel to the egg.

When trying to achieve pregnancy through intercourse, the capacitation process occurs in the female reproductive tract. During in vitro fertilization, this process must be stimulated in the collected sperm in order to successfully fertilize the collected eggs.

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