What Does Capacitation Mean?
Capacitation is the activation process that prepares the sperm for fertilizing the egg and begins once the sperm enter the upper female genital tract or uterus. The process prepares the sperm to undergo the acrosome reaction, which will allow it 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.
FertilitySmarts Explains Capacitation
After ejaculation, as the sperm enters the vagina, the acidic environment and secretions of the female reproductive tract prompt a chemical change in the sperm. The head of the sperm (the acrosome) becomes more permeable, allowing the release of the enzymes that will allow the sperm to bind with the egg during the process of fertilization.
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 removal of the outer protein layer on the head of the sperm. Removing this layer releases enzymes that allow the sperm to penetrate the outer layer of the egg (called the acro.
- 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 (IVF), this process is completed artificially by placing the collected sperm in an activating fluid before combining them with the collected eggs.