...and so it begins. Well not really, as the zygote, a fertilized egg, won't appear on the stage for another two weeks. But any great story, adventure, or journey must have a beginning, and I'll begin this one in Week 1 while the zygote and child that follow are little more than an idea. Besides, pregnancy term is 'counted' from the last time you've had a period... ...and we have important things to learn in a very limited amount of time.
For example:
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| Contestants, CNP, 2014 |
At the risk of sounding gross, sperm are pretty amazing. I think as a woman I have probably been in a very egg-centric world, a sort of 'my gametes are cooler than your gametes' kind of mindset. But after doing a lot of research on sperm, I have to say they are pretty impressive. Sperm are the smallest and most highly packed of all the human cells (which is a nice way of saying they are dense...) and so small that men's immune systems would attack and kill their own sperm, were it not for specialized Sertoli cells that protect the seeds. They are really streamlined:
- a long tail (although many sperm may have two or branched tails),
- several hundred (or more) mitochondria to power the jet propulsion, that are not, as far as we know, used in any way in the zygote,
- a "protonucleus," complete with half the DNA needed to create a human being (weird fact: sperm are sort of either male or female, some with a Y chromosome that will create male fetuses, and others with X chromosomes that will create females... so all men DO have a feminine side), and
- an acrosome, the 'hard hat' in the cartoon above. Once a sperm reaches the egg, which only perhaps one hundred of an initial 180 million do, the chemicals in the acrosome are released and help penetrate the layers of corona radiata cells surrounding the egg. The first sperm through? The only sperm that fertilizes the egg, and the provider of half the zygote's DNA.
On the other hand, the egg is massive. It is the largest of all human cells, and you can actually see it with the naked eye. This --> . <--is a period in 6-point font, and is about the size of a human egg. I know that doesn't seem very impressively large... ...you'll just have to take my word for it-- It Is Enormous! Eggs need to be huge though. They contain:
- half the DNA needed to code for a new being,
- ALL of the other organelles to sustain life, like mitochondria, Golgi apparatus, endoplasmic reticulum... ...all of these come from the egg,
- and a bevy of other associated cells that help with protection, transport, implantation, and eventual growth. I prefer to think of them as 'egg minions.'
You probably already know that women don't make eggs the same way that men manufacture sperm. And you probably know that women have all of their eggs 'ready to go' long before they ever reach an age that they can use them. You might be surprised at how long those eggs have been available, and how many there are. A five month old female fetus (!!!!) will have formed all of her initial million eggs, and will create no more in her lifetime. She will eventually ovulate 300-400 of them, and the rest will die off before they are ever used.
And what am I thinking during all of this first week? Am I overcome by the gravity of what is soon to take place in my body? Contemplating the eventual changes? Thoughts of bambinos? The meaning of life? Nope. I am not pregnant, and fairly blissfully ignorant of any impending changes about to happen.
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| Week 1, CNP, 2014 |
That will change, rather soon.
A note about these cartoons: I've done many cartoon series in the past, and since I'm embarking on what my mother calls the "greatest journey a woman can take," I'm going to share my pregnancy in this way--one or more cartoons a week, for forty (40?!?) weeks. Expect to find a little science, humor, mild whining, and a few moments of banal platitudes and perhaps absolute brilliance. I hope you will join me as I embark upon this adventure.
Until next week,
Cat
