Fertilization to implantation

Question 1

where fertilization normally occur

Answer 1

ampulla (widest part of fallopian tube)

Question 2

twins

Answer 2

identical - 1 sperm, 1 ovum (shared placenta)

fraternal - 2 sperms, 2 ovums (separate placenta)

Question 3

3 phases of fertilization

Answer 3

1. penetration of corona radiata - aided by tail and mucosal enzyme fallopian tube
2. penetration of zona pellucida - acrosome reaction occurs where cumulus cells are digested then cortical reaction prevent polyspermy
3. fusion of sperm and oocyte cell membrane - 2ndary oocyte completes meiosis II to form ovum