The story of becoming an independently functioning human is a long one. It starts with two cells that went through meiosis. They carry only half the chromosomes from mom and half the chromosomes from dad. Meiosis produces four cells. In females, three of those four are discarded, the last one becomes an egg. In males, all four products are used; you know them as sperm cells. The pre-birth story begins when one lucky sperm fertilizes an egg. In this moment, the two incomplete sets of chromosomes combine to form one full genome.
Fertilization, Then What?
The steps leading up to fertilization are probably the most fun, but we’re here to talk about the stuff that comes after. Assuming there are no chromosomal issues, the fertilized egg successfully grows and differentiates into specialized tissue and organs. One cell becomes two, then four, then eight, and so on and so forth. This is all thanks to the process of mitosis. Cells make exact copies of themselves all the time, but never has it been more important than after fertilization. Without mitosis and growth, we’d simply remain a single cell and quickly wither away.
The Human Tube
We’re at the point in this pre-birth story where the embryo is still a ball of cells. But did you know that humans don’t grow from the inside out? When the ball gets to a certain size, it actually folds in on itself or invaginates, creating a layered structure that essentially has a hollow tube running through the middle. The layers continue to grow and differentiate into muscle, bones, nerves, and organs. That tube though, never truly disappears.
Mouth to Anus
If you distill life down to its basic elements, you’ll find that no matter how big or small the organism, the same basic needs must be met. Life has one goal and that is to make more of itself. In order to do so, living things require energy from the surrounding environment. The tube that runs through all of us starts at the mouth and ends with the anus. It’s purpose? To break down food, absorb the molecules, extract energy, and eliminate waste. Any blockages in this tube quickly leads to death.
Get the Whole Pre-Birth Set
We wanted to celebrate all the major milestones that come before you get pushed out of the uterus. Our egg and sperm necklace memorializes the very first cell that is you. The 4-egg embryo piece is a snapshot of the importance of mitosis and the role it plays in shaping us, literally. If you found the Human Tube part particularly interesting, then you will love our blastocyst necklace; it’s what you looked like right before the tube formed. And finally, for those looking for something a bit more familiar, we have the embryo and fetuspieces. This collection of you before birth was made for all humans. While personal reasons might vary, professionally, they make great gifts for gynecologists, fertility experts, pediatricians, and starry-eyed pre-med students.
written by Science with Evie