Line 11: Line 11:  
== Pre-Implantation Development ==
 
== Pre-Implantation Development ==
    +
* The sperm enters the the oocyte forming the ootid.
 
* In the Ootid, male and female '''pronuclei''' along with the first and second '''polar bodies''' are present.
 
* In the Ootid, male and female '''pronuclei''' along with the first and second '''polar bodies''' are present.
 
* Fusion of the male and female pronuclei results in a single '''diploid nucleus''' ('''Syngamy''')
 
* Fusion of the male and female pronuclei results in a single '''diploid nucleus''' ('''Syngamy''')
 +
* This causes the '''zona pellucida''' to form around the zygote. This is an imprenetrable layer that prevents polyspermy and so polyploidy.
 
* '''Zygote''' (diploid) undergoes mitotic divisions ('''cleavage''').
 
* '''Zygote''' (diploid) undergoes mitotic divisions ('''cleavage''').
 
* Cleavage gives rise to daughter cells called '''Blastomeres'''.
 
* Cleavage gives rise to daughter cells called '''Blastomeres'''.
3,320

edits