Health dictionary - I

Health dictionary


The final and longest section of the small intestine. 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. Before immunisation, children often died from diseases like diptheria or polio. 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 has an inability to control the release of urine 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 nebulizer

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.


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 and disease; others mean you have a reduced chance.


This is when a substance is put into your body using a needle. There are different types of injection – including intravenous, intramuscular, intrathecal and subcutaneous.


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 diabetes often 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 PICU or 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.

Internal defibrillator

This is a small device that is inserted into the chest to monitor the heart’s rhythm. It can also control the pace of the heart’s beating by delivering small electric shocks.


This is part of your digestive system. You have a large intestine (also called the colon) and a small intestine. 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 hold in the middle called your pupil.


A kind of dye that shows up on x-rays and 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 eat and drink without actually eating or drinking. Confused? Don't be, it's just a way of getting the nutrients your body needs into your system when you're unable to actually eat or drink. It's also a way of getting medicines into your system when you don't feel like eating or drinking.