What is the digestive system?
The digestive system is the part of your body that helps turn the food you eat into energy and nutrients, helping you to grow and stay healthy.
When food is eaten, it goes into the mouth, where the teeth chew it into smaller pieces and saliva starts breaking it down.
Then it travels down a tube called the oesophagus to the stomach. There it is mixed with special acids and juices to make it mushy.
After that, the food moves into the small intestine, where nutrients are taken out and sent into your blood. The leftovers go into the large intestine where water is taken out before the waste leaves the body as poo and wee.
The digestive system is amazing because it turns food into the fuel that keeps the body moving and growing!
Watch: Small intestine goes to the doctor's
GPs are used to looking at all the different parts of the human body… but not quite like this!
DOCTOR STEVE: It's a life or death moment for Doctor Steve.
Yes! Hello?
PHONE CALL: Busy, doctor?
DOCTOR STEVE: Uh, yeah. No. Uh, what can I do for you?
PHONE CALL: There's a windbag to see you.
DOCTOR STEVE: That's a very rude way to speak about patients.
SMALL INTESTINE: Hello, doc.
DOCTOR STEVE: Never mind. I know who you're talking about.
Ah. Small intestine. A pleasure to see you.
Less of a pleasure to see what you've been digesting.
So, what seems to be the problem small intestine?
SMALL INTESTINE: Oh, that. That's what's wrong.
DOCTOR STEVE: What?
SMALL INTESTINE: Everyone calling me small, and I'm really massive.
DOCTOR STEVE: I know, if you were laid out straight, you'd be over six metres long. That's longer than a great white shark.
SMALL INTESTINE: Really?
DOCTOR STEVE: Oh, yes. You're actually longer than the large intestine. Which is quite funny when you think about it.
SMALL INTESTINE: Funny? It's wrong and embarrassing. I do all the hard work, absorbing nutrients from the food you eat.
And making farts.
Oh, the large intestine just absorbs water and salt and makes plops. And more farts.
DOCTOR STEVE: I can see and smell that you're very upset small intestine - I mean impressively long intestine. But the reason you're called small is because of your width, not length.
DOCTOR STEVE: Means you can fit into small areas. Which is one of your greatest strengths.
SMALL INTESTINE: Is it?
DOCTOR STEVE: Yes.
Look, you're all scrunched up like this, right? If I unfold you and spread you out like this, we see just how large you really are and how much surface area you have to absorb all the nutrients from all the food people eat as it passes through you.
SMALL INTESTINE: Huh? So it's a good thing that I'm small?
DOCTOR STEVE: Oh, yes. You wouldn't be able to fit inside people if you weren't. And then you couldn't do your amazing job.
SMALL INTESTINE: Oh thanks, doc. I feel so much better now.
Don't worry, doc, these are happy farts.
DOCTOR STEVE: I can tell it.
What is the small intestine?
The small intestine is a long, twisty tube inside you that helps the body get nutrients from food.
After food leaves the stomach, it goes into the small intestine. The food is then broken into tiny pieces that the body can use.
The inside of the small intestine has little finger-like shapes called villi*, which soak up the nutrients from the food. These nutrients then go into the blood which carries them all around the body to provide energy and help the body grow.
Even though it’s called ’small’, the small intestine is actually very long - about six metres! It’s just narrow, like a garden hose. The small intestine is an amazing worker that makes sure all the good stuff from food gets used properly!
Horrible Science fact
Everyone farts, even animals! It happens because the digestive system makes gas when it breaks down food. That gas has to come out somehow, so the body lets it escape as a fart. So fart with pride, it’s your body doing its job!
Find out more about the digestive system.
Quiz
How to use Horrible Science in the classroom
If you're looking to bring energy, humour and curriculum-aligned content into your science lessons, Horrible Science might just be your new secret weapon.
More on Horrible Science
Find out more by working through a topic
- count10 of 50
- count11 of 50
- count12 of 50
- count13 of 50
