Cells. We have a heck of a lot of them. A quick Google search indicates that there's some discrepancy as to exactly how many we have, but the consensus is up in the high trillions. And a trillion is an awfully big number, you know.
But what goes on inside them? To ponder that, we have to think on a much tinier scale than what we're used to. One of my favourite authors, Madeleine L'Engle, is excellent at doing just that. If you haven't already, I highly recommend reading A Wrinkle in Time and its sequel, A Wind in the Door. Not only are they both excellent books, they also force you to really think about our position in the universe and our composition as human beings. A Wrinkle in Time sets humans up as microscopic yet integral fibres in the grand tapestry of all existence, human and otherwise. And, as if you needed your worldview (universe-view?) broadened any further (and of course you do!), A Wind in the Door then proceeds to demonstrate that we're not complete units of existence ourselves. The climatic events of the story take place inside one mitochondrion, which is a tiny functional unit within one cell. Nothing has made me feel simultaneously so small and so enormously powerful like these two books, and I can't wait to finish the whole series.
So. What does Madeleine L'Engle have to do with biology at the cellular level? Well, she beautifully illustrates the fact that the state of being human is actually an amalgamation of trillions upon trillions of highly complex functions going on all the time in our body. These functions are extremely specialized. If just one minute process is not carried out exactly as it's supposed to be, we're screwed. Ignoring the universe for a second, let's think of the human body itself as a tapestry. If just one thread goes awry, suddenly our heraldic lion loses its fangs and isn't so tough anymore. And that's just embarrassing.
To keep our body running, we rely on a complex system of organs. We've all (hopefully) got our hearts, brains, lungs and livers. Each of our organs performs a very specific function essential to life. Just like the human body as a whole, each of our cells has organs too. We call those organelles--adorable mini-organs that are specialized in a similar way. Thanks to incredible advances in microscopy, we're able to see organelles up close and personal, which tends to really skew my thinking if I'm not careful. More than once (yes, I'm a nerd) I've caught myself looking at an electron microscope image of, say, a Golgi apparatus and thinking it must be some kind of folded-up tissue. Nope! The Golgi apparatus is an organelle, completely invisible to the naked eye.
I promise I'll explain what the Golgi apparatus actually does in a later blog post. It's just one of my favourite organelles to bring up because it makes me feel so smart every time I say it. Golgi apparatus. Golgi apparatus. Golgi apparatus. Try it at home (the second 'g' is soft).
While cells may look like they should be able to function on their own--after all, they've got their own organ(elle)s and everything--they can't. Not our cells, at least. If you don't weave the tapestry together, you've just got a tangled pile of thread. Your cat might like it, but it sure doesn't do us much good. Cells rely on each other to keep doing what they're doing, whatever that happens to be. Everything a cell does relies on specific chemical reactions, and the chemicals that they use have to come from the cells that produce them. Intercellular communication and cooperation is the key to life. Get enough cells together and in the right cooperative formation, and you've got an organ. A bone. A body.
I am going to explore organelles in greater detail later, but for now I just want to impress upon you, my dear reader, how incredibly awesome it is that we are so small in the face of the universe while essentially being a universe to the smallest known unit of life. How many components can the human existence be broken down to? Where does the body end and our environment begin? How far can we go in defining the human body before we are met by things we can't define? For me, these are questions not only of biology but of spirituality as well, and the more I learn, the more I believe that the two are inextricably linked in the story of our bodies, our universe, and beyond.
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