Health dictionary - I

Health dictionary


The final and longest section of the small intestine that absorbs goodness from what we eat and drink. It is attached to the colon.

Immune system

This is what fights off infections. When you’re born, antibodies that are passed on protect you from your mum. As you grow older, you develop your own antibodies.


All the injections you’re given when you’re growing up are designed to protect you against diseases. It’s important that you have all your immunisations at the right time. Some of them are given as a series of injections, where you have one when you’re a baby and then others as ‘boosters’.


The term used to describe somebody who cannot control the release of urine or poo from their body.


This is the medical word for the cut that the surgeon makes during an operation.


This is a device used to care for babies, especially those that are born early. The incubator does this by allowing health professionals to control the temperature, humidity and oxygen around the baby.


In medical terms, this is a baby up to a year old.

Inhaler or nebuliser

Being able to breathe is very important but asthma can sometimes make it more difficult. If you have asthma, running about or eating certain foods can irritate your airways and make it harder for you to breathe. An inhaler is a special gadget that sprays medicine into your mouth. It help you to relax and breathe more easily. A nebuliser delivers medicines into your lungs in a form that you breathe.


This is how genes pass on characteristics from your mum and dad to you. When red hair ‘runs in the family’, this means it has been passed on to you through your parents’ genes. Characteristics can also ‘jump’ generations, your parents may not have red hair, but maybe your granddad did! Certain diseases are also passed on from your parents. There are different kinds of inheritance – some kinds means you’re more likely to inherit a disease.


This is when a substance is put into your body using a needle. There are different types of injection – including intravenous (into a vein), intramuscular (into a muscle), intrathecal (into the fluid around your spinal cord) and subcutaneous (under the skin).


Insulin is a hormone made in the pancreas. The body releases insulin to help it store glucose (a form of sugar) received from food. People with type 1 diabetes may need to inject insulin as their body does not correctly control its output of the hormone.

Intensive care

The intensive care unit is sometimes called ICU. It's a special hospital ward where children are given lots of help. Doctors and nurses who have had extra-special training treat them.


This is part of your digestive system. You have a large intestine (also called the colon) and a small intestine (duodenum, jejunum and ileum). They work together to squeeze food through to your bottom, absorbing liquid and goodness along the way.


A type of injection that is given into a muscle.


A type of injection that is given into the spaces between the bones in your spine.


This is the coloured part of your eye. It has a hole in the middle called your pupil that opens and closes to let light inside the eye.


A kind of dye that contains radioactivity so shows up on scans.


If a word ends in ‘-itis’, it means that a part of your body is inflamed. For example, cystitis means that your bladder is inflamed.

IV or Intravenous

An IV (intravenous) drip allows you to get the nutrients your body needs into your system through your veins when you're unable to actually eat or drink. It's also a way of getting medicines into your system when you can’t eat or drink – some medicines also work better this way.