Health dictionary - H

If a word begins with ‘haem’ this usually means that it is something to do with blood. For example, haematology is the study of blood.

If you have blood in your wee, the doctors may say that you have haematuria. It’s usually caused by an infection in your urinary system. Sometimes, the amount of blood is so small, that you can only see it under a microscope.

This is what makes red blood cells red. It’s a kind of pigment that carries the oxygen to all parts of your body. Each red blood cell contains about 350 million haemoglobin molecules!

Your hands are really important – they help you hold things, grip things tight and also do small fiddly tasks too. What makes us different from animals is that we have something called ‘opposable thumbs’, which means that we can touch our thumb and fingers together to hold things. Like your foot, your hand is made up of lots of small bones.

This is the pump made of muscle inside your ribcage that keeps us all alive. Your heart pumps all the time to push blood around the body.

This is a collection of blood outside of a blood vessel. One of the most common forms of hematoma is bruising on the skin.

This means 'half' as in hemi-nephrectomy – an operation where half of your kidney is removed.

This is a condition where a muscle has a weak spot which lets your insides bulge out through it. It's fixed in an operation.

Your hip is the joint between your pelvis and your thighbone. It’s a ‘ball and socket’ joint which means you can move your leg in all directions.

A Holter monitor is a portable device that monitors the electrical activity in your heart over a 24-hour period. It involves putting stickers on your chest that link up to a recording device. This then monitors your heart rate, the shape of the complexes (in other words how each beat of your heart looks) and gives a very clear picture about how your heart rhythm is working.

These are chemical messengers that switch on and off processes in the body. For instance, starting puberty or producing more urine.

Your upper arm bone. It connects your shoulder with a ‘ball and socket’ joint and with your elbow with a ‘hinge’ joint.

When this starts a word, it means ‘too much’ of something.

When this starts a word, it means ‘too little’ of something.