06. Fertilisation

  1. Spermatozoa move into fallopian tubes

  2. Capacitation: increases permeability of cell membrane of sperm head

  •    Ca2+ absorbed, removing cholesterol, forming pores.

  1. Releases proteases to break down corona radiata and carbohydrase to digest zona pellucida

  2. Sperm and secondary oocyte membranes fuse triggering meiosis II

  3. Ovum and second polar body formed

  4. Cortical reaction occurs where cortical granules fuse with cell membrane to harden zona pellucida, preventing polyspermy

  5. Nuclei of sperm and ovum fuse forming diploid zygotic nucleus