5 I sleep

Is my body the same as everyone else's? You are the only person exactly like you in the whole world-that makes you very special! But although you are different from everyone else, your body is made of the same things as theirs. And it has exactly the same parts doing all the different jobs that keep you alive. Everyone's body has all the important parts shown below. These are some of the parts of the body that can be different. Hair can be dark, fair or red, curly, wavy or straight. Eyes can be different shades of blue, brown, grey or green. Noses are different shapes. Some people have freckles. Muscles can be big or small. Skin comes in lots of different colours. Some people are tall, some are small. Some people are fat, some are thin. Can you see the wavy lines in the skin on your fingertips? They are your fingerprints. No one else in the whole world has the same fingerprints as you.

What is inside my head? The most exciting and important part of your body is hidden inside your head, beneath your hair, your skin and your hard skull bone. It is your brain. Your brain is the part of you that thinks and remembers. It also makes sure the rest of your body is doing what it should! Your brain has two sides. The right side of your brain looks after the left side of your body, while the left side looks after the right side of your body. People's brains come in different sizes. But bigger brains don't make people more clever —any more than having big feet makes them better runners! What makes me feel things? Every minute of the day your brain is being sent messages about all the different things that are happening inside and outside your body. Some are about things you feel. All the messages travel to your brain along paths called nerves. Your nerves start in your brain, then travel in a thick bundle down your back. From there they branch out to every part of your body. Nerves tell your body what's happening to it—u like whether water feels too hot or too cold. Messages travel very fast along your nerves. The quickest go as fast as 400 km/h! Hurt or pain are feelings that tell you if something is wrong. They are your body's warning system. It hurts when you stub your toe because your body is telling you to stop- something is in your way!

How many bones do I have? When you were born, you had about 350 bones. But by the time you finish growing, you will have just over 200! The missing bones won't have fallen out or disappeared. Instead, as you get older, some of your smaller bones will join together to make bigger ones. Your bones are partly made of a hard stony stuff called caldum, but unlike stones they are alive. They get bigger as you grow up. Without bones inside you to give you a shape, you'd be like a floppy, squishy bag. Bones are hard and strong. They help to keep the softer parts inside you from getting hurt. The longest bone in your body is the one above your knee, called your thigh bone. Most of us have twelve pairs of ribs, but some people have an extra pair. Your ribs help to keep your lungs and heart safe. Although your skull is made of lots of bones, most of them are fixed together. Only your jaw bone moves. What is my funny bone? The funny thing about your funny bone is that it isn't a bone at all. It's a nerve that runs just under your skin over each elbow. If you bang your elbow, the nerve is banged, too. It sends a message to your brain and you feel pain!

What is my skin for? Skin is the stretchy bag you live in. It covers your whole body, holding your insides in and protecting them from the outside world. Your skin gets its colour from something called melanin. People with dark skin have more melanin than people with light skin. Whether your skin is light or dark, too much sun can burn you. Wear a hat and put on a layer of sun protection cream. How thick is my skin? In most places, your skin isn't much thicker than cardboard. But although it is so thin, lots of things happen inside it. Hair grows in skin, and sweat is made there. Skin also has blood vessels, and nerves to send messages to your brain. This is what skin looks like through a microscope. Hair grows out of a pit called a follicle. Sweat comes out of holes called pores. Sweat is salty water that your body makes when it's hot. What are goose bumps? When a cat is cold, its fur fluffs up. This traps a blanket of air next to its skin to keep it warm. Your hair also stands up when you are cold and shivery, and goose bumps? are made by tiny hair muscles tightening. This doesn't keep you very warm, though, because you're not hairy enough!

How do I move? Muscles make you move, by pulling your bones about. When you smile or cry, speak or eat, walk or skip, muscles are doing the work. A muscle can only make itself shorter. It needs another muscle pulling the other way to stretch it out again. To make a bone move, a muscle gets shorter. This pulls the bone one way. To pull the bone back again, another muscle gets shorter. Muscles are fixed to your bones by strong white strings called tendons. why do strong people have big muscles? Muscles get bigger and stronger if they are used a lot. That's why sportswomen and sportsmen practise hard and do lots of exercises. Your biggest muscles are the ones you sit on! Many tennis players have bigger muscles in the arm they use to hold their racquet. What is cramp? Cramp is when a muscle suddenly feels tight and painful. It stops moving properly and it feels like it's stuck. No one is quite sure why cramp happens, but it goes if you rest the sore part. Rubbing it can also help.

Why do I breathe? You pull air into your body when you breathe. And air is something your body cannot do without, even for just a few minutes. This is because air has a gas called oxygen in it, and your body needs oxygen to live and grow. When you breathe in, air goes down your windpipe to your lungs. These are like big sponges which hold air instead of water. If you fold your arms across your chest and breathe in, you'll feel your lungs getting bigger as they fill up with air. What makes me hiccup? There's a big muscle below your lungs which helps you to breathe. It's called your diaphragm muscle. You hiccup when something makes this muscle pull down really hard, drawing lots of air into your lungs. To stop too much air rushing in, a flap at the top of your windpipe clamps down. This closes off the air flow so quickly that your whole body jerks. What makes me sneeze? If dust or germs get into your nose, your body makes you sneeze to get rid of them. Your lungs shoot air out, clearing your nose. When you sneeze, air rushes down your nose at over 160 kilometres per hour!