The Hungry Microbiome Part 1: The Digestive System

By Jesse Hawley , Jesse Hawley

16 January 2015

3 minute read

A diagrammatic overview of our digestive system

A diagrammatic overview of our digestive system, by Armando Hasudungan. Imagine if our organs were actually labelled like that…that’d be handy.

Welcome to the first in a four part series on the digestive system.

You might know it as the alimentary canal, or maybe just ‘the food tube’. Whatever you like to call it, it can be easy to ignore the digestive system and all of its complexities – that is, until something goes wrong with it. So why not be ahead of the game and learn a little more about our insides?

Basically, the digestive system is a tube with two ends. Food, rich in nutrients, enters one end of the tube, whereupon our body works hard to extract all it can. After some days, the ‘food’ exits the other end of the tube, largely devoid of its nutrient content.

But that’s only part of the story. We sought the assistance of Armando Hasudungan, a biomedical animator and explanation extraordinaire, to explain what’s really going on in your digestive system.

This series is composed of 9 digestion-related animations, which will be broken up into four blogs.

Today’s animation is an overview of the digestive system, a journey from the mouth to the poop chute and everything in between.

Part 1: The Digestive System

We hope that wasn’t too much to swallow! But if you’re still hungry for some more alimentary enlightenment, here’s some further food for thought:

Your body is composed of 100,000 billion cells – each of which need food to keep functioning. Thankfully, these guys aren’t snacking on breakfast burritos. They only need extremely tiny portions of food, broken down by our teeth, acid and enzymes, which are in turn fed to them by even smaller capillaries – just one cell thick.

These food-bearing capillaries have a massive delivery area, nourishing cells at the furthest reaches of our bodies. It’s not an easy job, when you consider the unimaginably tiny scales they are working at. But these guys are responsible for satiating brain cells, eye cells, hair follicles and bone cells – essentially keeping our body running.

Close up image of a human eye.

Breakfast burrito in the eye. Photo by Christopher Porter, Flickr.

Of course, our bodies are only so good at breaking down foods. As you now know, our mouths have amylase, an enzyme to break down starch. But if you were to try eating cardboard or grass or sand (which we do not recommend) your body would not extract one iota of nourishment.

Of course, there are many single-celled organisms that can eat ‘cellulose’ – the structural chemical that makes cardboard and grass inedible. There are even bacteria that can digest minerals from rocks.

What’s that we hear you saying? If only we could somehow ingest these bacteria, these single-celled eating machines, and use them to get more nutrients from our food?

Well, evolution has got you covered there. Literally covered. We have more cells of bacteria covering our insides and outsides than we do human ones. In fact, for every human cell composing your body, there are 10 bacterial cells in and on you. And you call yourself an individual, pah! Yes, we have billions of bacterial cells in our digestive systems, with a concentration in our large intestine, which also goes by another name: the colon. But more on that later.

Over the coming weeks, our ‘Hungry Microbiome’ animations are going to focus on carbohydrates, their breakdown by our microbiome (the bacteria in our guts), and the various benefits of butyrate – the molecule released by our little colonic companions.

We can’t wait! In the mean time, you can see more of Armando’s videos here.