Fertilisation - Anatomy & Physiology
Revision as of 14:43, 3 July 2008 by Lwilkie (talk | contribs) (→Cortical Reaction - Block to Polyspermy)
Fusion with the Oocyte
- When the Spermatozoan completely penetrates the Zona Pellucida and reaches the Perivitelline Space, it settles into a bed of microvilli formed by the Oocyte plasma membrane.
- Oocyte plasma membrane fuses with the equitorial segment and the fertilizing Spermatozoon is engulfed.
- Brought about by a fusion protein that is inactive prior to the acrosome reaction.
- Nucleus of the Spermatozoon is within the Oocyte cytoplasm.
- Sperm nuclear membrane disappears.
- Sperm nucleus decondenses.
Cortical Reaction - Block to Polyspermy
- During the first and second meiotic divisions of Oogenesis small,dense cortical granules move to the periphery of the Oocyte cytoplasm.