Totally Tubular

You know how scientists always get excited about nematode worms? I kind of get it now.

In particular, C. elegans has been touted as a key to understanding human biology. It’s about as simple as you can get insofar as animal bodies go. There are only about a thousand total cells, and only 302 neurons total. If you’re starting to feel like I’m insulting your intelligence, that’s not the portion of the biology I want to focus on for now.

Because of the relatively tiny number, we’ve been able to map C. elegans completely and thoroughly. We now know how every single one of those cells connects to each of those neurons.

Why should this be such a good proxy for critters as complex as human beings? One answer is that, like nematode worms, we are really mainly a series of tubes.

Take eating, for instance.

You chew the food up, swallow it, and it heads down that tube that is you. Up here, it’s the esophagus, not your windpipe—that’s another tube that makes you up. From your esophagus, the food continues, digesting along the way, through a continuous network of other tubes that are, truly, just one long tube.

Small and large intestines? Tubes connected to your esophagus at one end (tube) and your rectum at the other end (tube).

It’s almost like you swallowed a hose once upon a time.

In the middle of this tube, your poop partnership takes place.

Your stomach is always ready for this little squished nugget when it arrives. Here, those stomach acids I heard so much about in 1980s Tums ads do their magic, mixing with those food nuggets and kind of stirring them around until they become like a paste called chyme.

You can read the full story if you want to, but the main idea is that food goes in one end of the tube, and dookie comes out the other.

That’s not the only way we humans are, effectively, just glorified series of tubes. Your heart blasts blood out into your body through a series of tubes, and then that same blood comes back into your heart for additional processing. Throughout all those tubes on the way out, oxygen is delivered to your body so it can continue to function.

Tubes, I tell ya!

There’s also the whole breathing tube we’re all equipped with at birth. Oxygen comes in from the outside air, and is delivered to the lungs by way of the tracheal tube. Your body has all sorts of clever devices like the epiglottis to make sure the right stuff is in each tube.

Eventually, these tubes need to meet in order for the real magic to happen, so tiny air sacs called alveoli deliver pure oxygen into the network of blood tubes.

So, there you have it—we are all series of tubes, and here I am delivering this message to you through another series of tubes.