The digestive system
Apr 12, 2006 3:13 PM
Ever wondered what happens to your food once it passes your lips? Well, once you've taken a mouthful, your food embarks on an incredible journey... |
Your tastebuds
You have roughly 10,000 tastebuds on your tongue, which come alive the moment you put food in your mouth. As nerve endings, they're responsible for sussing out the chemicals in the food you've eaten and transmitting messages to your brain. Without them you wouldn't be able to experience salty, bitter, sweet or sour sensations.
While your tastebuds are busy at work, your teeth grind the food into easily digestible pieces and your saliva moistens everything, so it doesn't scrape your digestive (gastrointestinal) tract on the way down.
Stomach
Once you've swallowed your food, it's carried down the oesophagus to your stomach. Here, your stomach walls churn the food up to make sure it's mixed with your acidic digestive juices. By the time your tummy has finished, the food is a creamy mixture called chyme (pronounced kime). Once it's liquefied it can be squirted through a small hole into your small intestine.
Small intestine
This is where most of the nutrient-digesting action happens. To help your small intestine cope with the acidity of the chyme, your pancreas releases an alkaline and lots of enzymes, which break down the food's carbohydrates, fat and protein. Meanwhile, your gall bladder donates some bile to ensure any fat is melted down thoroughly.
Once the food is reduced to tiny particles, it's absorbed through the walls of your small intestine and the nutrients are carried into your bloodstream.
Did you know...?
- The average digestive tract is roughly the length of a double-decker bus.
- An average stool is 75 per cent water. The remainder is made up of fibre, dead cells and bacteria.
- The acids in your stomach are so strong, they kill bacteria and are similar to those used in industrial metal cleaner.
Large intestine
Any nutrients that can't be digested end up here, including fibre, which has certain components that can't be absorbed by the human body. Your large intestine begins at the colon, where some of the remaining nutrients can be mopped up. After this point, anything that's left over is waste matter and is stored in the rectum, waiting for the journey's end.
This article was last medically reviewed by Dr Rob Hicks in September 2005.
First published in March 2001.
