Skip to content

Help and information

This topic takes on average 55 minutes to read.

There are a number of interactive features in this resource:

Topic last updated: 24 Nov 2021
    • Ico Chemistry Chemistry
    • Ico Human Biology Human biology
    • Ico Science Science
    • 7-11
    • 55

Medicines to treat disease

  of  6

Medicines in the body

Simple animations show how a medicine that is swallowed, inhaled or injected can travel round round the body to get to where it is needed.

Breathing and Asthma

Breathing moves air into the lungs. Oxygen goes into the blood and is carried around the body to the cells where it is used. Carbon dioxide – a waste product from the cells – is carried back to the lungs in the blood, moves into the lungs and is breathed out.

The heart pumps blood around the body. When the blood returns to the heart, it is then pumped to the lungs to pick up some more oxygen. The oxygenated blood returns to the heart to be pumped on around the body again.

In an asthma attack, the lining of the tubes which carry the air into the lungs swell up. This makes the tubes narrow get narrow which makes it difficult to breathe. This is shown on the animation. An asthma inhaler (sometimes called a "puffer") is used to relieve the symptoms. The medicine is carried down into the lungs. As it goes through the tubes, it works by reducing the swelling. The tubes get wider again and breathing goes back to normal. This is shown on the animation.

Medicines by injection

An injection puts the medicine straight into your body, so it gets into the blood stream very quickly. The animation shows the blood circulating around a simplified circulatory system. When an injection is given the medicine is seen circulating round in the blood.
Injections make sure that a medicine is carried all around your body very fast.
Any medicine which gets into your blood stream is carried to every part of you within a very short time indeed. It will affect all of your body, not just the part that feels ill. It reaches your brain and all your other body organs. This is why it is so important that you only take medicine which has been prescribed or given to you, and that you take the right dose.

Medicines by mouth

If a medicine is swallowed it moves through the gut wall into the blood.

Once the medicine gets into your blood stream it is carried to every part of you within a very short time indeed. It will affect all of your body, not just the part that feels ill. It reaches your brain and all your other body organs. This is why it is so important that you only take medicine which has been prescribed or given to you, and that you take the right dose.

Taking a spoonful of medicine

Show animation full screen in new window