The activation of sperm is called capacitation.
Capacitation is a crucial process that sperm must undergo in the female reproductive tract to become capable of fertilizing an egg. It involves a series of biochemical and physiological changes that enhance the sperm's motility and enable it to penetrate the egg's outer layers. This process essentially prepares the sperm for fertilization.
Here's a breakdown of what happens during capacitation:
- Changes in the Sperm Plasma Membrane: The sperm's outer membrane undergoes alterations in its lipid and protein composition. This includes removal of cholesterol and some surface proteins.
- Increased Intracellular Calcium: An influx of calcium ions into the sperm cell occurs, leading to increased flagellar activity and hyperactivation.
- Hyperactivation: Capacitated sperm exhibit a vigorous, whiplash-like swimming motion called hyperactivation, which helps them navigate through the female reproductive tract and penetrate the egg's outer layers.
- Acrosome Reaction Preparation: Capacitation primes the sperm for the acrosome reaction, a process where enzymes are released from the acrosome (a cap-like structure on the sperm head) to digest the outer layers of the egg, allowing the sperm to fuse with the egg cell membrane.
In summary, capacitation is a complex maturation process sperm undergo in the female reproductive tract, essential for enabling them to fertilize an egg.
