The heart sits in our chest. The heart is so precious it is protected by our ribs and breastbone.

The heart pumps blood around our body, and beats over 100 000 times every single day. It is a hard worker isn't it!

If you weigh 40 kilograms you will have just over 3 litres of blood in you body. Have a look at the milk container in your fridge and see how much that is.

Blood carries oxygen, food, water and waste products to and from every single cell in our body.

Make a fist with your hand. That is about the size of your heart in your chest.

Your heart is like a balloon and has thick walls made of muscle. When it relaxes it fills up with blood, like when a balloon fills with water. The muscle then squeezes the blood out into our body, like when you squeeze the balloon and the water squirts out.

The blood travels all through our body in veins and arteries, like different sized hoses.

We have one liver and it sits just under our chest on the right side of our body.

The liver is very important as a filter for our blood. Just like a pool filter, the liver receives all the blood from our body and makes sure the blood stays nice and clean.

The liver also produces things to help our body digest the food we eat. Digest means to change the food we eat into things that help us to grow and stay alive.

For example, if you eat a slice of cheese, our liver will help to change the cheese into calcium which helps our bones grow and stay strong. If we drink some cordial, our liver will help change the sugar in the cordial into energy to keep us active.

We have 206 bones in our body. Bones are important in movements such as walking and even talking.

Bones are also important protection for special parts of our bodies.

What does our scull protect that is so important? What do our ribs protect?

Bones are growing all the time. They help you to grow into adult size and even when you are an adult our bones rebuild themselves. This is why a bone that is broken can heal back together in a plaster caste.

Dairy products and lots of exercise help us to keep our bones healthy and strong.

We have two kidneys.

If you put your hands behind you, you can feel your ribs going around to your back. Your two kidneys sit one each side of your back underneath your ribs.

If you make a fist of your hand, that is about how big your kidneys are. They are shaped like a jelly bean.

Kidneys filter the blood of waste and water. The waste and water turns into urine and is stored in our bladder. We have one bladder and this sits below our belly button. Both kidneys are joined by a special tube (ureter) to take the urine to the bladder.

When the bladder fills up with urine we go to the toilet to empty our bladder. We have to empty our bladder up to ten times every day, depending how busy our kidneys have been.

Some people say they were busting to go to the toilet, this means their bladder was so full it felt like it would burst!!

We have two eyes. Eyes allow us to see the world. Seeing is one of our five senses. Do you know what the other four senses are?

The black centre of our eye is called a pupil. Pupils control how much light is needed to see. You can see how the pupil does this by shining a torch into someone's eye. Because the torch is a bright light, the pupil will become small, to shut out some of the extra light that is coming into the eyes.

What would happen if you were in a dark room? What would the pupils do to get as much light as possible into your eyes?

The iris is the colour around your pupil. What colour is your iris? Some people have a blue iris, some brown and some green.

The white part of the eye is called the sclera, and this covers the eye.

Did you know your eyebrows and eyelashes help to keep dust out of your eyes. If dust gets in, our eyes will push it out by lots of blinking and tears.