By the end of med school, I would have already watched all of your videos 'cause whenever I'm looking for some explanation, you got a video for that. Thank you so much!
Great lectures. You present your knowledge very clearly. It's a shame you don't get much recognition for your great, and laborious efforts. Keep up the good work! Thank you!
Very helpful, thanks for all your hard work! However, I think it would have been useful to mention how the egg has the corona radiata outside of the zona pelucida and that the sperm has to break down the hyaluronic acid to bury through those granulose cells. Also, I think it's helpful to know that the egg is stopped in metaphase II prior to the Ca wave during which enzymes allow for meiosis to resume.
Something I don't understand is that it has been said that the oozyte undergoes Meiosis II AFTER the fertilization which results in the haploid chromosome set. Is the fertilization then seen only as the penetration of the sperm through the plasmamembrane? I mean the two chromosome sets can only fuse when both are haploid, right?
The secondary oocyte undergoes meiosis 2 once the sperm binds to the zona pellucida. So once the sperm binds to the zona pellucida, the secondary oocyte quickly undergoes meiosis 2 to become an ovum and then fertilisation occurs. So it's DURING fertilisation, not after :)
Yes, it does encounter with corona radiata first and penetrate it before it releases the enzyme (hyaluronidase and acrosin) to drill the hole in zone pellucida to get to the oocyte. We have had med-student losing points for not mentioning the corona radiata, but I think that he is mentioning the main processes and skipping some details. I watch the videos before reading my books just to get the greater picture before digging in to the details :)
