5. The Digestive System
Digestion is the how the body breaks down food so it can be taken in and used. There are many organs in the digestive system each with a particular job to do.
Food passes down through:
- The Mouth
- Small Intestine
- Large Intestine
Other organs such as the liver and pancreas also play a role in digestion by producing chemicals that help to break down food.
Even before you eat, when you smell a tasty food, see it, or think about it, digestion begins. Saliva or spit, begins to form in your mouth.
When you do eat, the saliva breaks down the chemicals in the food a bit, which helps make the food mushy and easy to swallow
The oesophagus is like a stretchy pipe that's about 25 centimetres long. It moves food from the back of your throat to your stomach. But also at the back of your throat is your windpipe, which allows air to come in and out of your body. When you swallow a small ball of mushed-up food or liquids, a special flap called the epiglottis flops down over the opening of your windpipe to make sure the food enters the oesophagus and not the windpipe.
If you've ever drunk something too fast, started to cough, and heard someone say that your drink "went down the wrong way," the person meant that it went down your windpipe by mistake. This happens when the epiglottis doesn't have enough time to flop down, and you cough involuntarily (without thinking about it) to clear your windpipe.
Once food has entered the oesophagus, it doesn't just drop right into your stomach. Instead, muscles in the walls of the oesophagus move in a wavy way to slowly squeeze the food through the oesophagus. This takes about 2 or 3 seconds.
Your stomach is a stretchy sack shaped like the letter J. It has three important jobs:
- to store the food you've eaten
- to break down the food into a liquidy mixture
- to slowly empty that liquidy mixture into the small intestine
The stomach is like a mixer, churning and mashing together all the small balls of food that came down the oesophagus into smaller and smaller pieces. It does this with help from the strong muscles in the walls of the stomach and gastric juices that also come from the stomach's walls.
The small intestine is a long tube that's packed beneath your stomach in lots of tight turns – if stretched out it would measure about 5 to 6 skipping ropes. (6.7m)
The small intestine breaks down the food mixture even more so your body can absorb all the vitamins, minerals, proteins, carbohydrates, and fats.
Your food may spend as long as 4 hours in the small intestine and will become a very thin, watery mixture. During this time all the nutrients from your food have passed into your blood stream
Whilst the Larger intestines are wider they are in fact smaller than the small intestines if stretched out; measuring about 1 and a half metres.
Once most of the nutrients are removed from the food there is only waste left over — stuff your body can't use. This stuff needs to be passed out of the body. And there’s only one way for to exit…….Can you guess? Well, here's a hint: It goes out with a flush.
In the large intestines the body tries to absorb any remaining water and juices from the waster until all that is left Is a solid. You might call it poop. The large intestine pushes the poop into the rectum. The solid waste stays here until you are ready to go to the bathroom.