How Sperm is Prevented from Entering the Egg: Key Mechanisms Explained

Discover the mechanisms that stop sperm from entering the egg, ensuring successful fertilization and preventing polyspermy.

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Several mechanisms prevent sperm from entering the egg: the zona pellucida, a protective outer layer of the egg, and the cortical reaction, which hardens this layer once the first sperm penetrates. These barriers ensure only one sperm fertilizes the egg, preventing polyspermy.

FAQs & Answers

  1. What is the zona pellucida? The zona pellucida is a protective outer layer surrounding the egg that prevents multiple sperm from fertilizing it.
  2. Why is polyspermy problematic? Polyspermy can lead to abnormal fertilization and developmental issues, which is why mechanisms exist to prevent it.
  3. What happens during the cortical reaction? The cortical reaction occurs when the egg's membrane hardens to block additional sperm after the first one penetrates.
  4. How does sperm penetrate the egg? Sperm must first breach the zona pellucida and then trigger the cortical reaction to successfully fertilize the egg.

Watch More

To learn more about the fascinating science of fertilization and reproductive health, check out our videos on sperm function and egg development.

  1. Do All Sperm Wait for the Egg? Understanding Fertilization Dynamics Explore whether all sperm wait for the egg and learn about the fertilization process.
  2. Can an Egg Reject All Sperm? Understanding the Selection Process Discover how an egg selects sperm for fertilization and the biochemical interactions involved.
  3. How Does Sperm Fertilization Work? Discover how sperm fertilizes an egg and what leads to pregnancy in this informative Q&A video.
  4. What Happens Right After Sperm Enters a Woman’s Body? Discover the journey of sperm after entry into a woman and the potential for fertilization and pregnancy.
  5. How Can the Female Body Reject Sperm: Understanding the Mechanisms Explore how the female body can reject sperm, including immune responses and cervical mucus roles.