Conception + fertility Flashcards
The first polar body is found in which structure?
Perivitelline space
Once sperm enter the female reproductive tract, which process do they have to undergo to allow them to fertilise an egg?
Capacitation
Which 2 processes does capacitation prepare sperm for?
Acrosome reaction
Increased motility
In capacitation, what change increases the sperm’s membrane fluidity?
Change in the lipid composition of the sperm’s plasma membrane
Which process accounts for fertilisation being more successful if sperm are present before ovulation / arrive early?
Capacitation
Fusion of a sperm with an ovum produces which new cell?
Zygote
Immediately after fertilisation, there is an increase in the concentration of which ion in the egg?
What is the function of this?
Increase in calcium ions
Causes cortical granules to fuse with the membrane and prevent polyspermy
After fertilisation, what fuses with the egg membrane to prevent polyspermy?
Cortical granules
What are the 5 stages of embryo development?
Pronucleate
Cleavage
Compaction
Blastocyst
Hatching
What happens during the pronucleate stage of embryo development?
2 separate pronuclei, one from the sperm and one from the egg, prepare to merge
What happens during the cleavage stage of embryonic development?
This is when the single-celled zygote starts dividing rapidly — but without growing in size
So, you get more and more smaller cells called blastomeres, all still inside the same original outer shell (the zona pellucida)
The embryo now looks like a little cluster of identical cells
What happens during the compaction stage of embryonic development?
Blastomeres start to flatten and stick tightly together, forming a more cohesive structure
Which stage of conception is most likely to fail in IVF treatments?
Implantation
How is infertility usually defined?
1-2 years of a couple unsuccessfully attempting to conceive
