Health dictionary - B

Health dictionary


A type of germ or bug which can make you ill. They’re treated using antibiotics.


This is a substance that shows up well on x-rays. It can either be swallowed or put up your bottom so the doctor can see your digestive system and check for any abnormalities.


Something that is slow-growing or won’t spread anywhere else. You can get benign tumours, which won’t spread throughout the body, for instance.


When a part of your body isn't working quite right, doctors need to be able to see what's going wrong. Sometimes, they decide to do a biopsy, which means they take a really small section from that part of your body. Scientists can then carry out tests on the piece of tissue, in the laboratory.


This is a mark on your skin that is there when you are born or develops very soon afterwards. They can be brown, red or even a blue colour.


Your bladder is a bag made of muscle, which holds urine (wee) until you go to the toilet.. The amount of urine the bladder holds varies from person to person – some people's bladders can hold a lot of urine, other people's don't hold as much.


Your blood flows all around your body through arteries, veins and capillaries. It's made up of different types of blood cell – red blood cells, white blood cells and platelets – all suspended in a liquid called plasma.

Blood count

A test on a sample of blood that counts how many of each type of blood cell is present. It’s used as a general check that you are well or not.

Blood gases

A test that shows the amount of certain gases, like oxygen and carbon dioxide, are in your blood. It’s usually used to check whether you’re breathing effectively and getting enough oxygen.

Blood groups

There are lots of different blood groups – A, B, AB and O – and everyone has one. Blood groups are important if you’re having a blood transfusion, as certain blood groups won’t be accepted if you have a different one to the donated blood.

Blood pressure

Blood pressure shows how hard your heart is working to move blood around your body. When the doctor puts an arm-band around one of your arms and starts pumping air into it, they're checking your blood pressure.

Blood sugar level

This means the amount of glucose (a form of sugar/carbohydrate) in blood.

Blood transfusion

A way of replacing blood lost during an operation or after an accident. Before you have a blood transfusion, you’ll have your blood group checked to make sure your body will accept the transfusion.


This is a normal reaction to being embarrassed, or sometimes scared. The tiny blood vessels in your cheeks swell to let more blood through, which is what makes you go red.


These make up our skeleton. Bones are made from substances like calcium and phosphorus which make them strong. Inside some of our bones is bone marrow.

Bone marrow

You never actually get to see your bone marrow but it is very important. It's thick, squishy stuff that produces special blood cells that can develop into any sort of blood cells protect you against infection and makes sure oxygen gets to every corner of your body.


The main organ in your nervous system. It’s where you think, speak and have feelings. It also controls lots of other things in your body, like breathing and temperature, which happen without you having to remember to do them.


How you take in oxygen from the air around us, and transfer it into your blood where it can travel all around your body.


These are the two tubes that connect the bottom of your windpipe to your lungs.


A type of drug used if you have asthma. They work by opening up the passages in your lungs so you can breathe easier. You usually take them using an inhaler or ‘puffer’.


A test where the doctor can look inside your lungs using a flexible tube with a camera and light on the end. You’ll usually have this test under a general anaesthetic, so you won’t know what is happening.


We all get bruises if we knock ourselves on something or fall over. Bruises happen because the tiny blood vessels just under the skin burst so that the blood leaks out a bit. This is what makes your skin go blue. As a bruise is healing, the area goes yellow, which shows that the body is breaking down the blood and getting rid of it.