🍎 A Bite’s Journey: The Digestive System

Hello! You took a bite of an apple. That bite is now setting off on a long journey: the mouth, the gullet (oesophagus), the stomach, the small intestine and the large intestine. We call this the digestive system. Let’s follow the bite!

The journey starts in the mouth. Our teeth break the bite into small pieces: this is mechanical (physical) digestion. Enzymes in saliva start to break the food into even smaller substances: this is chemical digestion.

When we swallow, the bite enters the gullet. Muscles in the wall of the tube squeeze one after the other and push the bite down towards the stomach. No digestion happens in the gullet. The bite is only carried along.

The bite reaches the stomach. The stomach muscles churn the food: this is mechanical digestion. Stomach juice breaks the food down chemically. In the end the bite becomes a thick mush.

The mush moves into the small intestine. Here digestion is finished and the food is broken into very tiny particles. The wall of the small intestine is folded, so it has a very large surface. The particles pass from here into the blood. This is called absorption.

Two helper organs join in the digestion. The liver makes bile, and bile helps to digest fats. The pancreas makes digestive juice and sends it to the small intestine. Food does not pass through these organs.

The leftovers that cannot be digested arrive in the large intestine. It takes back the water and some salts from the waste and gives them to the blood. What is left is passed out of the body.

Let’s sort digestion into two groups. Mechanical digestion breaks food into small pieces: chewing with the teeth, squeezing of the stomach. Chemical digestion uses juices and enzymes: saliva enzyme, stomach juice, pancreas juice.

Let’s look after our digestive system: chew our food well, drink plenty of water, eat foods with fibre and brush our teeth. Then the bite’s journey goes smoothly.

Summary: the bite starts in the mouth and passes through the gullet, stomach, small intestine and large intestine. Teeth and muscles do mechanical digestion, and juices and enzymes do chemical digestion. Food passes into the blood in the small intestine. The liver and pancreas help. Now try it in Cell City!