USBORNE HOTSHOTS
YOUR
BODY
USBORNEHOTSHOTS
YOUR
BODY Written by Susan Meredith Des D esign igned ed by Fi Fion ona a Jo John hnso son n Illus Ill ustra trated ted by Kuo Kuo Kan Kang g Che Chen, n, Colin King and Sue Stitt
CONTENTS 4 Wh at is your body made made of of? ? 6 Wh er e doe does s your food go to? 8 Wh y do you breathe breathe? ? 10 Wh at is blood for? 12 You r skin 14 Me Mess ssag ages es fr om outside out side you 18 Inside yo your ur head head 20 Wh at makes makes you move? 22 Ho w are babies babies mad made? e? 24 Wh at makes makes you ill? ill? 26 Looking after you r body 29 Amazing facts about
Series editor: Judy Tatchell Series designer: Ruth Russell Additional illustrations by Chris Lyon, Guy Smith, Annabel Spenceley and Peter Wingham
your body 32 Index
What is your body made of? Your body is made of more than 50 million million living units called cells. Most cells are so small that you can only see them with a powerful microscope. The cells are about two-thirds water. Food and oxygen mix together inside them to give you energy.
The cells' instructions
This is a group of skin cells, magnified many times. One cell This part controls the way the cell works. It is called the nucleus.
Different kinds of cells Cells are different shapes and sizes depending on the job they have to do.
Nerve cell
Nucleus Chromosome
The nucleus in each cell contains special threads called chromosomes. These carry the instructions the cell needs to live and work. You inherit your chromosomes from your parents. Chromosomes are made of a chemical called DNA, which looks a little like a twisted ladder.
Growing and repair Until you are about 18, your body keeps making more and more cells. This makes you grow. Even when you are grown up, your body continues making some new cells. These replace the millions that die every second. A new cell is made when an existing cell divides in two.
Part of a chromosome. The rungs on the DNA "ladder" form thecoded instructions.
Nerve cells are very long. Messages travel along them. The cell takes in goodness from food and grows.
Muscle cell cell Nucleus
Muscle cells are long and thin. They can shorten their length (contract) and then relax, which makes you move.
Cells lining your nose and windpipe have tiny hairs on them. These waft germs and dust away from your lungs.
The nucleus dividesandthe cell starts to narrow in the middle. The cell splits in two.
The rungs on the DNA "ladder" are arranged in a different order in different people. This makes the instructions different, and makes everybody unique.
Nucleus Cells lining nose
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Where does your food go to?
Moving along
Without food to use as fuel, your body would soon stop working. Before your body can use it, the food has to be broken down inside you. This process is called digestion. The digested food goes into your blood and is carried to every tiny cell in your body.
Food does not just slide through your digestive tube. It is squeezed along by muscles in the tube. Muscles squeeze here.
Digestion
Oesophagus
Digestion takes place as your food travels through a long tube winding from your mouth to your bottom.
Food is pushed along.
Stomach Food
Your teeth bite and chew your food into small pieces. Saliva (spit) moistens it and makes it easier to swallow. Saliva has a digestive juice in it which starts breaking breaking up the food. W hen you swallow the food, it goes down your oesophagus into your stomach.
Teeth Stomach In your stomach the food is churned up and mixed with stomach juice. It becomes rather like soup.
The hardest substance in your body is the enamel coating on your teeth. There are 32 teeth in a full adult set and 20 in a set of first or "milk" teeth. Your teeth are anchored in your jawbone by long roo ts.
Small intestine Your stomach releases food into your small intestine. Juices finish digesting it. The digested food seeps through the thin walls of your small intestine into your blood.
Look on the opposite page to find out what different parts of the digestive tube do. Small intestine
Waste water Any water that your body does not need is turned into urine (pee) in your kidneys. These are in your back. Urine is stored in your bladder until you go to the toilet.
Large intestine Water and any food which cannot be digested move into your large intestine. Most of the water goes into your blood through the walls of your large intestine.
Large intestine
This picture shows the position of your digestive system. 6
Rectum
Anus
Rectum Solid waste is stored at the end of your large intestine in your rectum. It is pushed out through your anus when you go to the toilet. 7
Why do you breathe?
How you breathe
Before your body can use the energy which is in your food, the food has to be mixed with oxygen. This is a gas in the air. When you breathe in, you take oxygen into your body.
Your breathing is controlled by muscles between your ribs and by your diaphragm muscle, which is below your lungs.
When food and oxygen are combined in your cells, energy is released. At the same time, a waste gas, called carbon dioxide, is made. You get rid of this when you breathe out.
Oxygen goes in. Ribs move up and out, expanding the space in your lungs. Diaphragm moves downward.
Your lungs
Carbon dioxide and water go out. Blood vessel
Ribs move down and in, squeezing air out. Diaphragm relaxes
Your lungs Your lungs are in your chest.
upward.
The air you breathe is sucked through your nose or mouth, down your windpipe and into the branching tubes in your lungs.
Voice box Air in and out
At the ends of the tiniest tubes are bunches of air sacs. These fill up with air, like balloons. You have about 300 million air sacs in each lung.
Carbon dioxide seeps out of blood into air sac.
from air sac.
The air sac walls are only one cell thick. Oxygen seeps through them into your blood. Your blood carries it to all your body cells and brings brings back carbon dioxi de. 8
Blood vessel
Vocal cord
The lumpy part at the front of your Your voice neck is your box bo x is here. voice box.
You have some stretchy cords, called vocal cords, in your voice box. When you speak, you breathe out and air passes between the cords. It makes them vibrate and produce sounds.
High sounds
Low sounds
Muscles in your voice box alter the shape of your vocal cords to produce high or low sounds. 9
What is blood for? The main job of your blood is to carry food and oxygen to your cells. It also collects up waste for disposal. Your blood is pumped by your heart. It flows around your body in tubes called blood vessels.
Blood Blood consists of a mixture of cells floating in a pale yellow liquid called plasma. Digested food and waste products are carried in your plasma.
Heart and blood vessels Your heart is about the size of your fist and is made of muscle. It keeps squeezing so blood spurts out of it into your blood vessels. There are three types of blood vessels: arteries, capillaries and veins.
Red blood cells pick up oxygen as your blood passes through your lungs. This turns them bright red.
H ea rt
Arteries are blood vessels which carry blood away from your heart. Blood in your arteries is full of oxygen and is bright red. Capillaries are tiny blood vessels. They pass between all the cells of your body. Their walls are so thin that substances can pass in and out of them, to and from your cells. Veins are blood vessels which carry blood back to your heart. Blood in your veins is purplish-red because the oxygen has been used up.
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Circulation White blood cell help to fight off illnesses. They Platelets help cuts to surround and stop bleeding. They destroy germs. plug up the wound . by making a clot
Your blood always goes in the same direction around your body, as shown here.
Heartbeat
Pulse
Your heartbeat is the sound made by two pairs of valves, like gates, in your heart. They slam shut after each surge of blood has gone through. This stops the blood from flowing back. You have valves in your veins,
Every time your heart pumps, your arteries throb as blood surges through them. You can feel this throbbing, or pulse, at your wrist.
Your skin
Hot or cold?
Your skin is not just a bag to hold your body together. It also protects you from the outside world. It is about 2mm (0.08in) thick over most of your body and is arranged in two main layers: the outer epidermis and the inner dermis. Your surface skin is dead. This strong protective covering gradually gets worn away but new cells from the bottom of the epidermis are growing up all the time to take its place.
Dark or fair? Your skin produces a dye called melanin. The more melanin you have, the darker your skin. In strong sunlight extra melanin is produced as protection against the sun's rays. This is why peoples who originated in hot, sunny climates have dark skin.
Hair Your hair grows out of pits called follicles. Cells at the root of the hair divide and push it upward. As your hair grows, the ends get so far away from your blood that they die. Having a hair cut is painless, because the hair is dead.
Goose pimples
When you are hot, your blood vessels widen so that more blood can flow near the skin's surface and be cooled by the air. This makes you look red. When you are cold, the blood vessels narrow to prevent heat loss and you look paler.
You get goose pimples when you are cold because tiny muscles attached to your hairs contract. This makes the hair on your body stand on end. This is not much use to humans but in furry animals the hairs trap air. This helps to keep the animal warm.
Waterproofing
Sweat
Your skin is coated with oil made in groups of cells called sebaceous glands. The oil helps to keep your skin and hair waterproof and supple.
Sweat is mainly water and salt, which pass into your sweat glands from nearby blood vessels. The sweat comes out through holes called pores. The air cools you as it dries the sweat on your skin.
Messages from outside you Information from the outside world comes to you through special nerve cells called receptors. When these are stimulated by light or sound, for example, they produce tiny electrical impulses, which travel along nerves to your brain. Your brain sorts out what they mean.
Big or small pupils
Tears
When it is dark, your pupils expand to let in as much light as possible. In bright light they shrink to prevent damage to your retina.
Every time you blink, tears wash over your eyes and clean them. Right eye
Tearsaremade under your top eyelids.
How you see Everything you see has rays of light bouncing off it. The light goes into your eyes through the pupil (the black dot in the middle). Behind the pupil is a lens. This bends the light rays so that a clear picture of what you are looking at fits onto the back of your eye (the retina). Receptor cells which react to light are in your retina. They send impulses your brain.
This part of your eye is called the iris.
Muscles in the iris change the size of your pupils.
Tears drain into your nose through the inside corner of your eye.
You can watch your pupils changing size. Try looking at them in a mirror, first in a bright place, then in a dim one.
If you get something in your eye, extra tears are made to wash it away. Nobody knows why people cry when they are upset.
Taste The "whites" of your eyes protect the parts behind. Your eyelashes help to keep dust and dirt out of your eyes.
Your tongue has tiny spots called taste buds on it. Receptor cells in the taste buds sense four different tastes: tastes: sweet, sour, salty and bitter. Different parts of your tongue pick up the different tastes.
Lowereyelid
As this eye looks at the rocket, the light rays that come from the rocket cross each other behind the lens, so that the picture on the retina is upside down. The brain turns the picture back the right way up.
Smell Receptor cells high in your nose are sensitive to smells. They sense subtle tastes too. This is why you can't taste much if your nose is blocked up.
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Loud noises
How you hear Sound is really vibrations in the air. These affect receptor cells right inside your ears. The outside of your ears is like the big end of a funnel. It collects sounds and directs them down a tube, called called th e ear canal. canal.
Where the sounds go The sounds hit a piece of thin, tightly-stretched skin called the ear drum and make it vibrate.
The vibratio ns pass pass along a chain of three tiny bones and then to a coiled tube called the cochlea.
Fluid Fluid in the cochlea shakes around and pulls on hairs in the receptor cells. These send electrical impulses to the brain.
This chart shows the approximate loudness of certain sounds. Loudness is measured in decibels (dB). Repeated exposure to loud noise, say through headphones, can damage the receptors in your ears and make you deaf.
Touching and feeling
Receptor cells in your skin have different shapes.
You have pain receptorcells deep inside you as well as in your skin. Pain helps to protect you by warning you when something is wrong.
Balancing When you move your head, fluid in the semi-circular canals swirls around and pulls on receptor hair cells. These send impulses to your brain, which tell it about your position.
If you spin around and then stop, you may feel dizzy. This is because the fluid in the canals continues to swirl for a while, even though your body is still. This confuses your brain. 16
Receptor cells in your skin respond to different sensations such as heat, cold, light touch, pressure, itch or pain. You have lots and lots of receptor cells in your mouth, fingers and the soles of your feet. A tiny hurt in one of these places can feel much worse than a hurt in a place with fewer nerve endings. 17
A mouth ulcer can be very painful because you have so many receptor cells in your mouth.
Inside your head
Parts of the brain
Your brain controls your body and makes sure that all the different parts of you work together. It makes sense of what happens to you and enables you to think, learn and feel. Rather like a computer, your brain receives information, processes it and decides what action to take.
Brain and nerves Your brain is connected to all parts of your body by nerves. Messages go to and from your brain along the nerves in the form of electrical impulses, also called nervous impulses. 3. Brain notices, "That's an itch!"
Follow the numbered labels to see how a message travels to and from your brain.
Different parts of your brain have different jobs to do. There are some parts that nobody knows much about. They are probably to do with thinking, memory and making decisions.
Funny bone 4. Message goes from brain to hand: "Scratch itch."
2. Message goes along
nerve to brain from nerve ending (receptor) in arm.
The main pathway for your nerves is inside your backbone.
Sleeping
You can't normally feel the impulses as they travel along your nerves. However, your funny bone is very close to a nerve and the shooting pain you get when you bang it is an electrical impulse.
Dreaming may be a way of making sense of what has happened to you
Your brain works even when you are asleep. It makes sure your heart keeps beating and that you breathe and digest your food.
Two halves of the brain
Rapid reflexes
Each half of the brain controls the opposite side of the body. This is because the nerves to the two sides of your body cross each other as they leave your brain.
If you prick your finger, you pull your hand away immediately. This automatic reaction is called a reflex. It helps to protect you from danger.
The right side of your brain controls the movements of your left hand.
To do this as fast as possible, the impulses bypass your brain and go from your spine to your muscles. 19
What makes you move? Your skull protects your brain. Your ribs protect your heart heart and lungs.
Your muscles
You are able to move the different parts of your body because of the way your muscles, bones, brain and nerves all work together.
Your skeleton Besides helping you to move, your skeleton gives your body shape and stops it from collapsing. It also protects parts of your body.
What's in a bone? The outside of your bones is very hard but the inside is softer and spongy. It is arranged in a meshwork, which makes it light but strong. Some bones contain a substance called marrow. Blood cells are made in the marrow.
Many of your muscles are arranged in layers over your skeleton. They are attached to your bones by strong cords called tendons. You can see and feel your biggest tendon, just above your heel. You can also see tendons on the inside of your wrist when you clench your fist and at the inside of your elbow when you bend your arm
How muscles work When you want to move part of your body, your brain sends impulses along nerves to your muscles, telling them to contract (shorten). As they contract, they pull on your bones and make them move.
Joints The place where two bones meet is called a joint. Most joints are movable. Here are just two types.
Most of your muscles work in pairs. While one muscle is contracting, its partner relaxes.
Hinge joint at knees and elbows.
Ball and socket joint at hips and shoulders.
Your bones are held together by strong threads called ligaments. Knee joint
They are cushioned by pads of a rubbery substance called cartilage and oiled by a special special flu id. Without the cartilage and fluid, your bones would grind together. 20
Cartilage
Fluid Ligament
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Raising your eyebrows uses over 30 muscles.
How are babies made?
A baby develops
A baby starts to grow when a special cell from a woman, called an ovum or egg cell, and one from a man, called a sperm cell, meet and join together inside the woman's body.
Sperm cells Sperm cells are made in a man's two testicles. These are inside a bag of skin, which hangs behind his penis. Sperm can travel from the testicles along two tubes and out of the end of the penis.
Tube
Together, the egg and sperm make one new cell. This cell divides to make two cells exactly the same. These two cells then divide to make four. The cells continue dividing until a whole ball of cells is made. Thecell divides.
The ball of cells settles down in the lining of the woman's womb. There, it gradually develops into a baby until, after nine months, it is ready to be born. A baby is born through its mother's vagina. Penis
A ball of cells
Testicle
Egg cells
Eye A baby after one month in the womb.
A woman's egg cells are stored in her two ovaries. Once a month, an egg cell travels from one of the ovaries down one of the tubes leading to her womb.
Growing up When you are around I I years old (girls) and 13 (boys), changes start taking place in your body as you grow into an adult. This time is called puberty. The main purpose of the changes is to enable you to have children when you are grown up.
When a man and woman have sex, the man's penis gets stiffer and fits inside the woman's vagina. Sperm come out of the penis and swim up into the woman's womb and tubes. If the sperm meet an egg, one of them may join with it. This moment is called conception or fertilization. 22
Having a period Every month, the lining of a woman's womb gets thick and soft with blood, in case a baby starts to grow there. If this does not happen, the lining and the egg cell, which has come from the ovary, break up and trickle out of the woman's vagina with some blood. This is called having a period.
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What makes you ill?
How germs spread
Most everyday illnesses are caused by germs and are called infections. Germs are tiny living things, which are everywhere. Not all of them are harmful. The symptoms of infection, such as fever, are caused by germs damaging your cells and by your body fighting back. The main types of germs are bacteria and viruses.
Bacteria
Viruses
Bacteria are so tiny that over a million could fit on a pinhead. Some cause illnesses such as ear and skin infections.
Viruses are over a million times smaller than bacteria. They cause many common infections such as colds, sore throats and stomach upsets. Viruses have strange shapes.
Some bacteria attack your cells by giving off poisons. They can also spread infection around your body in your blood.
Viruses attack by getting inside a cell. The cell then becomes a kind of factory for making new viruses.
Most germs spre spread ad through through the air. Whe n you cough, sneeze or just breathe out, you spray tiny droplets into the air. This can spread illnesses such as colds and flu to other people. Covering your mouth and nose when you cough or sneeze helps stop germs from spreading.
Try not toshare other people's towels, if they have an infection.
Some skin infections, such as cold sores or warts, can be spread from one person to another by touching the infected place.
A blood vessel magnified many times.
Fighting back When germs damage your cells, more blood flows to the infected place. Some of your white blood cells then devour the germs (see page I I). Other white blood cells kill germs using chemicals known as antibodies. Antibodies can recognize germs that have attacked you before. They stay in your body to stop the same germs from attacking again. This means you only catch most infections once. Being protected like this is called being immune.
What is an allergy?
No medicines can get rid of viruses. Your body has to fight them off by itself.
Medicines called antibiotics can be used to kill bacteria that cause illness. 24
Germ
Allergies are not caused by germs. An allergy is when white blood cells send out antibodies to fight ordinary things as if they were germs. An allergy to pet hairs or feathers can cause the wheezing and coughing of asthma, or the sneezing and itchy eyes of hay fever.
Looking after your body There are several things you can do to help you stay healthy. Here are some of them.
Eating well Different foods do different jobs in your body, so you need to eat a good balance of all the different types. Eating the right amount is important too: neither too much nor too little. Protein foods make you grow and help repair your body. Meat, fish, eggs and nuts contain protein.
Carbohydrates give you energy. Bread, cereals, cereals, ri ce, pasta and potatoes are good energy foods.
Foods to cut down on Sugar gives you energy but has no other benefits; it rots your teeth and too much of it makes you overweight. Burgers and French fries are fatty.
Sweets and fizzy drinks are very sugary.
Too much fat can make you overweight. Animal fat, which is found in foods such as meat and butter, contains a substance called cholesterol. Over time, this can cause your arteries to get blocked and lead to heart disease.
Some foods, for example milk shakes, ice cream and biscuits are mostly fat and sugar. Some people are allergic to additives, such as food dyes and preservatives, which are put into many foods.
Keeping clean
Fruit and vegetables contain vitamins and minerals. You need these to keep your body working efficiently.
Milk, cheese and yogurt contain calcium, which makes your bones and teeth strong. They also contain protein.
Fibre is a carbohydrate that your body cannot digest. It is good for your digestive system, though. It prevents constipation and may protect against some serious illnesses. Fibre is found in wholemeal bread and pasta, wholegrain cereals, brown rice, fruit and vegetables. 26
You need to wash every day to get rid of dirt, dead skin, oil and sweat. This helps to prevent germs from growing and spreading on your skin. Your hair needs to be washed regularly for the same reasons. Brushing your hair helps to keep headlice away. Always wash your hands after going to the toilet, and before eating or handling food. This helps to stop many germs from spreading, especially those that cause stomach upsets. Your mouth contains bacteria which feed on any tiny pieces of food and drink left on your teeth. As they feed, they produce acids which make holes in your teeth. Cutting down on sugary foods and drinks, and brushing your teeth regularly help to prevent tooth decay.
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Food
You have lots of sweat glands under your arms.
Tooth decay leads to toothache.
Amazing facts about your body
Exercise Exercise is good for you in lots of ways. 1. It makes you strong by making your muscles bigger and stronger. Without exercise, muscles waste away and turn to fat. 2. It strengthens your bones and keeps your joint s supple, so they do not stiffen up and give you aches and pains. 3. It makes your heart and lungs more efficient so that they can do more work with less strain. 4. It makes you less likely to pick up infections and to develop illnesses, such as heart disease, later on in your life. 5. It helps to keep you slim. 6. It helps you to relax and makes you feel good.
The best exercise for your whole body is swimming.
You need to exercise regularly to get fit, so it is important to do a sport you enjoy. The best are those which have as many of the benefits listed on the left as possible. These include swimming, soccer, energetic dancing and cycling.
Smoking, alcohol and drugs You may meet people who encourage you to smoke cigarettes, drink alcohol or take drugs. These can be habit-forming, so that once you start using them it is hard to stop. They can be extremely harmful.
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Cell lifespans Some of the cells in your body live longer than others. For example, cells in your small intestine get worn away by food and live for only a few days, whereas some nerve and brain cells last a lifetime. Type of cell
Average lifespan
Cells of small intestine
2-3 days
Taste bud cells
7 days
Skin cells
3 weeks
Red blood cells
4 months
Bone cells
25-30 years
Muscle cells
Most last a lifetime
Nerve and brain cells
Some last a lifetime
Small intestine? Your small intestine is "small" only because of its width: just 4cm (1.5in). It is actually very long: about 4m (13ft) if it were uncoiled. Long slow journey A meal stays in your stomach for about three hours and can take three days to travel all the way through your digestive tube.
Hic! Hic! You get hiccups when the diaphragm muscle in your chest gets out of control, making your in-breaths come in short gasps. The noise is caused by your vocal cords snapping shut. Voice breaking The longer your vocal cords, the deeper your voice. In their early teens, boys' voices get much deeper or "break". This is because their vocal cords grow twice as fast as girls'. Pumping blood At rest, a child's heart beats about 80 to 100 100 times a minute. An adult's heart beats about 70 times. When you exercise, your heart beats harder and faster. An average adult has about 5 litres (8.5 pints) of blood in their body. Red blooded You have about 30 million million red blood cells, more than any other type of cell. Red cells are made in your large bones, at a rate of about three million a second. These cells have no nucleus. 29
Thin skinned? Although your skin is about 2mm (0.08in) thick in most places, it is only 0.5mm (0.02in) thick on your eyelids and 6mm (0.2in) thick on the soles of your feet. A rhino's skin is about ten times thicker than your skin.
Brainbox The average human brain weighs about 1.4kg .4kg (3lb). It is thought that the brain can store about as much information as a 20-volume encyclopedia.
Colour blind Some people have faulty receptor cells in their eyes and cannot see colours correctly. About one in 20 people cannot tell the difference between red and green.
Lightning reactions When you are awake, about three million nervous impulses flash around your body every second. Some of these travel at over 400kmph (250mph), which is faster than a high-speed train.
Colour blind view
With normal colour vision
A good sniff Your smell receptor cells cover an area about the size of a postage stamp but they allow you to detect over 3,000 smells. Some dogs, however, can smell about a million times better than that.
Nervous tension An adult has some 75km (45 miles) of nerves in their body, enough to stretch over 185 times around an Olympic running track. How many bones? You have over 200 bones. Around half of them are in your hands and feet. Your Your thigh bone is both the longest and strongest bone in your body.
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How much muscle? You have over 600 muscles. The largest are in your bottom but the strongest are the ones you use for biting at each side of your mouth. Biggest and smallest cells The biggest cells in the human body are female egg cells. Each is about the size of the dot over this letter letter " i " . The The smallest cells are in your brain. They are 100 times smaller than egg cells. Bacteria invasion Your body is a warm damp place with plenty of food, so bacteria grow and spread quickly inside you. Within hours there can be millions in one small par t of your your body. Atchoo! Sneezing sprays millions of germs into the air. Some of them may shoot out over 3m (I0ft)
Common complaints The two mo$t common infections are colds and gum disease. disease. Scientists estimate that about four out of five people suffer from gum disease at some time in their lives.
Water of life You could live for several weeks without food but only only for a few days without water. There is water not only in drinks but in food too. Lettuce and carrots, for example, are both nine-tenths water How much energy? The energy you get from food is measured in kilojoules (kj) or kilocalories (kcal). Different foods have different a m o u n t s of kilocalories. kilocalories. Between Between the ages ages of ten and fourteen you need around 2,000 to 3,000 kilocalories a day: about the same as an adult. Apple 50kcal
away.
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Index antibodies 25 arteries 10, I I, 27 balancing 16, 19 bladder 7 bones 20, 21,30 brain 18-19, 30 capillaries 10 cartilage 20 cells 4-5, 29, 31 cholesterol 27 chromosomes 5 circulation I I conception 22 diaphragm 9, 29 digestion 6-7, 26, 29 DNA 5 dreaming 19 ears 16, 17 egg cells 22, 23, 31 energy 4, 8, 26, 27, 31 exercise 28, 29 eyes 14-15, 30 fat 12, 27, 28 fertilization 22 food 4, 6, 7, 8, 10, 10, I I , 26-27, 3 I germs 11, 24-25, 27 growing 5, 26
hair 4, 12, 13, 27 receptors 14, 15, 16, hearing 16, 17, 19 17, 18, 30 heart 10, 11,20,28,29 reflexes 19 hiccups 29 retina 14, 15 ribs 9, 20 intestines 6, 7, 29 saliva 6 join ts 20, 28 sight 14-15, 19, 30 kidneys 7 skeleton 20, 21 skin 12-13, 17,29, 30 ligaments 20 sleeping 19 lung lungs s 8-9, I I , 20,28 smell 15, 19, 30 sperm 22, 23 marrow 20 stomach 6, 7, 29 melanin 12 muscles muscles 4, 21 , 28, 31 sweat 13, 27 nerves 4, 14, 18, 19, 21,30 nose 4, 15, 16 oesophagus 6 ovaries 22, 23 ovum 22 oxygen 8, 9, 10, I I penis 22 periods 23 plasma I I platelets I I pores 13 puberty 22 pulse I I pupil 14, 15
taste 15, 19, 29 teeth 6, 7, 26, 27 tendons 21 testicles 22 thinking 18, 19 touching 17, 19 urine 7 vagina 22, 23 veins 10, I I vocal cords 9, 29 waste 7, 8, 10, I I wat er 4, 7, 9, I 3, 31 windpipe 4, 8, 9 womb 22, 23
This book is based on material previously published in Usborne Starting Point Science: What's Inside You?, Inside You?, Where do Babies Come From?, What Makes You IIP, Young Scientist: Human Body. Facts Facts and Lists: Body Facts. First published published in 1996 1996 by Usborne Publishing Ltd, Usborne House, 83-85 Saffron Hil l, London ECIN 8RT, England. Copyright © 1996, 1993, 1992, 1991, 1983 Usborne Publishing Ltd. The name Usborne and the device are Trade Marks of Usborne Publishing Publishing Ltd. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher. Printed in Italy.
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