fertilisation - Cortical reaction

• what is meant by the cortical reaction

  this is the process of the zona pellucida hardening to form the fertilisation membrane
• When does the cortical reaction occur?

  after one sperm had penetrated the secondary oocyte
• what happens to the oocyte once the sperm has penetrated the secondary oocyte

  the oocytes smooth endoplasmic reticulum will release calcium ions into the cytoplasm
• what is released from the oocytes smooth endoplasmic reticulum once a sperm ahs entered the secondary oocyte

  calcium ions
• what is the function of calcium ions in the cortical reaction

  it will cause the cortical granules to fuse with the cell membrane
• what will happen in the cortical reaction once the cortical granules have fused with the cell membrane

  the cortical granulates will release their contents to modify the zona pellucida
• how will the zona pellucida be modified in the cortical reaction


  it will harden
• what is another name for a hardened zona pellucida

  fertilisation membrane
• what does the formation of the fertilisation membrane prevent

  polyspermy
• what is polyspermy


  fertilization by more than one sperm
• why is it important that polyspermy is prevneted

  the oocyte could receive too many chromosomes resulting in a unviable zygote
• what does the entry of a sperms genetic material into a secondary oocyte trigger

  meiosis 2
• what does meiosis 2 of a secondary oocyte form

  an ovum and a polar body
• what is formed when a nuclei of teh sperm and the ovum fuse together

  a zygotic nucleus
• what is the name of a fertilized ovum

  a diploid zygote