smithsonian Did You Know? Human Body SMITHSONIAN INSTITUTION Established in 1846, the Smithsonian Institution—the world’s largest museum and research complex—includes 19 museums and galleries and the National Zoological Park The total number of artifacts, works of art, and specimens in the Smithsonian’s collection is estimated at 137 million, the bulk of which is contained in the National Museum of Natural History, which holds more than 126 million specimens and objects The Smithsonian is a renowned research center, dedicated to public education, national service, and scholarship in the arts, sciences, and history smithsonian Did You Know? Human Body Emily Dodd Contents Author Emily Dodd Consultant Dr Bipasha Choudhury Smithsonian consultant Darrin Lunde, National Museum of Natural History, Smithsonian Institution Illustrators Dan Crisp, Arran Lewis DK LONDON Editor Katie Lawrence Senior art editor Ann Cannings US Editor Margaret Parrish US Executive editor Lori Hand US Senior editor Shannon Beatty Additional editing Manisha Majithia, Olivia Stanford Managing editor Jonathan Melmoth Managing art editor Diane Peyton Jones Senior production editor Robert Dunn Production controller Barbara Ossowska Jacket designer Ann Cannings Jacket coordinator Issy Walsh Publishing manager Francesca Young Creative director Helen Senior Publishing director Sarah Larter DK DELHI Project editor Radhika Haswani Senior art editor Nidhi Mehra Project art editor Bharti Karakoti Managing editor Monica Saigal Managing art editor Romi Chakraborty Jacket designer Rashika Kachroo Jacket editor Radhika Haswani DTP designers Sachin Gupta, Vijay Kandwal CTS manager Balwant Singh Production manager Pankaj Sharma Project picture researcher Sakshi Saluja Delhi creative heads Glenda Fernandes, Malavika Talukder First American Edition, 2021 Published in the United States by DK Publishing 1450 Broadway, Suite 801, New York, NY 10018 Copyright © 2021 Dorling Kindersley Limited DK, a Division of Penguin Random House LLC 21 22 23 24 25 10 001–321673–Mar/2021 All rights reserved Without limiting the rights under the copyright reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the copyright owner Published in Great Britain by Dorling Kindersley Limited A catalog record for this book is available from the Library of Congress ISBN: 978-0-7440-2664-1 DK books are available at special discounts when purchased in bulk for sales promotions, premiums, fund-raising, or educational use For details, contact: DK Publishing Special Markets, 1450 Broadway, Suite 801, New York, NY 10018 SpecialSales@dk.com Printed and bound in China For the curious www.dk.com This book was made with Forest Stewardship Council™ certified paper—one small step in DK’s commitment to a sustainable future For more information go to www.dk.com/our-green-pledge Body basics 8–9 10–11 12–13 14–15 16–17 18–19 20–21 22–23 24–25 Piece by piece 28–29 30–31 32–33 34–35 36–37 38–39 40–41 42–43 44–45 46–47 48–49 50–51 What are bones made of? What is my biggest muscle? What’s between my brain and skull? What’s inside my heart? Are my ribs bendy? How does my spine fit together? Why I need plants to breathe? How does my brain control my emotions? Why doesn’t it hurt when I cut my nails? Why are my teeth different shapes? Why does sugar taste sweet? Why does my foot fall asleep? How it works 54–55 56–57 58–59 Smithsonian What’s my body made of? What is the largest organ? What’s smaller than a cell? Why is blood red? What is DNA? Why twins look the same? Why don’t I have my mom’s nose? Are bacteria alive? What are hormones? How can I feel light things? Why don’t I ever forget to breathe? Why can I jump? Find out how doctors can see inside your body on page 118 60–61 62–63 64–65 66–67 68–69 70–71 72–73 74–75 76–77 78–79 80–81 82–83 84–85 86–87 88–89 How bones help me hear? Why my pupils change size? How I balance? Why don’t icy drinks make me cold all over? Am I taller in the morning? How I remember things? What happens to the food I eat? Why can’t I breathe underwater? Why I burp? How babies grow? Does my skin last forever? How I hold my pee? Why I get goose bumps? Why I have eyebrows? Why my ears pop? Healthy habits 92–93 94–95 96–97 98–99 100–101 102–103 104–105 106–107 108–109 110–111 Why I need food? What happens when I exercise? What is mental health? Why I feel happy and sad? How does soap kill germs? Why people think differently? What happens when I age? Why I need water? What is my body clock? What happens when I’m scared? Find out how you breathe on page 56 Medical marvels 114–115 How X-rays work? 116–117 Why I need vaccinations? 118–119 Can magnets show what’s inside my body? 120–121 How antibiotics kill bacteria? 122–123 How doctors know what’s wrong? 124–125 Can my cells change jobs? 126–127 How does sunscreen work? 128–129 Can robots perform surgery? 130–131 How can doctors create body parts? 132–133 134–137 138–139 140–143 144 Answers Quiz your friends! Glossary Index Credits and acknowledgments ? Quick quiz Test your knowledge! Look for the “Quick quiz” box throughout this book to see how much you’ve learned You’ll find some of the answers on the pages, but you may have to look up or make your best guess for the others Turn to pages 132–133 for the answers Body basics The human body is made up of cells, which contain unique instructions that make you who you are Each organ in your body has an important job to do, and your blood helps to supply them with everything they need to work BODY BASICS What’s my body made of? The smallest living building blocks in the body are cells There are many different types of cell The same cells join together to build tissue Groups of tissues build organs, which work together in organ systems, such as the respiratory system Tissue Tissue builds every part of the body Some tissue creates strong structures, such as bone, while others make soft parts, such as nerves or muscle Cells Cells hold the instructions to make a body; these are written in a coded sequence of chemicals called DNA The DNA is kept in the nucleus— the center of the cell This cell is about to divide into two cells It has copied itself and made another nucleus 130 MEDICAL MARVELS How can doctors create body parts? Some people are born without certain body parts, and others lose them due to sickness or an accident Some of these people find it helpful to have a doctor create a body part for them—here are some examples Doctors can also perform a transplant operation This is when an organ from one body replaces an affected organ in another body What is a transplant? When an organ is not working properly, doctors can remove the same organ from another body to replace the affected organ Many body parts, such as the liver, can be transplanted After a transplant, the body needs medicine to make sure it doesn’t reject the new organ ? Picture quiz can The liver n self, eve it w o r g re o-thirds w t o t p if u issing! of it is m This organ can be transplanted into the body What is it? See pages 132–133 for the answers 131 Dentures False teeth, or dentures, are made from either plastic, nylon, or metal They fit over the gum and look just like real teeth They can be taken out and cleaned at night Bionic hand This electrical hand is wired into the arm muscles The brain sends signals to the muscles in the arm, which in turn move the hand Prosthetic leg Pacemaker This prosthetic leg is made from a lightweight material called carbon fiber It can bend without breaking, which makes it useful for runners Prosthetic legs can also be made of foam padding and plastic A metal pacemaker is fitted when a heart needs help to pump A tiny computer in the pacemaker sends out an electrical signal, which makes the heart pump at the right time 132 Answers Page 1) Cells 2) The nucleus 3) Organs Page 11 1) True They are also part of the respiratory system 2) False The largest organ is the skin 3) False You can survive with one kidney Page 13 A red blood cell Page 15 1) False Veins carry blood to the heart 2) True 3) False White blood cells fight off germs Page 16 1) In the nucleus 2) Genes switch on and off to tell the cell what to 3) A double helix Page 19 1) It’s very thin and tightly coiled up 2) Nothing! Only about percent of DNA does something 3) Half of your DNA comes from each of your parents Page 21 1) One set comes from each of your parents 2) Inheritance Page 23 1) True 2) True Page 25 1) True 2) False They are chemical signals 3) False Nerves are the fastest signals in the body Page 29 1) Fat 2) They are arranged with spaces in between layered tubes, which make the bones really strong when pushed from above 3) Cartilage Page 30 1) Skeletal muscles 2) Biceps Page 33 1) Three 2) Supplies nutrients and acts as a shock absorber 3) Your spinal cord Page 34 1) The valves snapping shut 2) Oxygen 3) Arteries Page 37 1) False 2) False Page 39 1) Disks of cartilage 2) By fluid and membranes Page 59 In the thumb Page 61 1) True 2) True Page 41 1) False They this during respiration 2) False They Page 63 1) To stop too much are located in the lungs 3) True light from getting in 2) The iris 3) They get bigger Page 43 1) Hippocampus 2) Four Page 65 1) False They are located in the ear 2) False Your Page 45 1) Old, dead skin cells eyes help you to balance but 2) The nail matrix 3) In summer you use other information, too 3) True Page 46 1) True 2) True It also protects them 3) False Most Page 67 1) From hot to cold babies are born with no teeth 2) The hypothalamus Page 48 1) False Too much sugar is bad for your health 2) False Taste detectors are only in the taste buds 3) True Page 69 1) True There is no gravity in space to squash you down 2) False You stretch out overnight 3) True Page 50 A nerve cell Page 71 1) Five 2) Neurons 3) Episodic memory Page 55 1) Receptors 2) Braille Page 57 1) To release carbon dioxide 2) It relaxes 3) No The brain controls it Page 73 1) Break down fat 2) Usually around two days Page 75 A frog 133 Page 77 1) Yes When you eat or drink very fast you swallow more air than if you eat slowly 2) Eructation Page 79 1) A fetus 2) An embryo 3) From the placenta and through the umbilical cord Page 81 1) False It’s thickest on your elbows and feet 2) False It’s made at the base of the epidermis Page 83 1) Receptors send a signal to the brain 2) They fold 3) Sphincter muscles Page 85 1) False It makes it stand up 2) True 3) False They contract, or pull Page 87 1) True 2) True 3) False You raise your eyebrows to show surprise Page 89 The stapes Page 93 In fat Page 94 1) True 2) True 3) False You use up calories when you exercise Page 97 1) Practicing mindfulness or talking to a counselor 2) Having good relationships, enjoying life, or expressing your feelings 3) Losing interest in things, having problems sleeping, or a change in your eating pattern Page 99 1) Chemicals are released 2) They connect us to others and they signal how we are Page 101 A virus Page 103 1) Children with dyslexia find it more difficult to read than other children their age 2) Your family’s behavior can affect the way you think Page 104 1) True 2) False Your skin produces less oil as you get older, so it dries out Page 107 1) In cells 2) Through your pee and poop, through sweat, and through your breath 3) You pee less and in smaller amounts Page 109 1) False It grows faster in the summer 2) True Page 111 1) In the hands, feet, and under the arms 2) It prepares the body to fight or run away 3) It slows down Page 115 b) Holes inside your teeth Page 117 1) Attack and destroy viruses 2) White blood cells 3) It can be injected into your blood or given to you to swallow or inhale Page 119 1) Magnetic resonance imaging 2) To see if there is a problem without having to operate 3) Radio waves Page 121 1) True 2) True Washing your hands is a great way to kill bacteria Page 123 1) 98.6°F (37°C) 2) Diagnosis 3) A stethoscope Page 125 In the uterus because it’s an early embryo Page 127 1) False It is outside the visible spectrum of light, so it is invisible 2) True Page 129 1) True 2) True 3) False They are remotecontrolled and can’t make their own decisions Page 130 A heart 134 hat is the W sm Who knows the most about the human body? Test your friends and family with these tricky questions See pages 136–137 for the answers Questions t organ in the s e l b al y? od Quiz your friends! What is the top part of the tooth called? What are the three bones in your middle ear called? 12 What type of scan uses magnets to show what’s inside your body? 135 W What are rodshaped bacteria known as? chambers are inside your heart? Who invented the first vaccine? What pattern are dead skin cells arranged in? un d? fo What are the tiny bumps that cover your tongue called? h tin e re era i n the body is k How many 10 What device can be used to measure your temperature? 11 Which organ can regrow itself if some of it is missing? 13 Where are adult stem cells made? 14 For how long should you wash your hands? 136 Answers ad skin cells are e D in a tessellated pa d e t te ng rn ar The smallest organ in the body is the pineal gland 11 The liver 13 Adult stem cells are made in the bone marrow 137 Bacillus bacteria Your heart Nails, hair, and skin contains four chambers he crown T The tiny bumps that cover your tongue are called papillae The three bones ward Jenner d E 10 A thermometer in your middle ear are called the malleus, incus, and stapes 12 Magnetic resonance imaging (MRI) scan 14 You should wash your hands for at least 20 seconds 138 Glossary absorb Take in something Your blood absorbs oxygen from your lungs allele Particular variant of a gene We get alleles from each parent for the same thing, such as nose shape bacteria Tiny, one-celled living things that live almost everywhere Some cause disease and others help your body blood vessels Tubes that carry blood through your body body clock Natural clock in the body that controls daily functions, such as sleeping carbon dioxide One of the gases in the air You release carbon dioxide when you breathe out cartilage Tough, flexible tissue in the body cells Smallest living part of your body cerebrospinal fluid Fluid that surrounds and protects the brain, also known as CSF characteristics Features of your body that are controlled by genes, such as nose shape chromosomes Tiny bundles of wound-up DNA diagnosis Process of identifying someone’s illness by looking at their symptoms and doing tests diaphragm Muscle under your lungs that helps you to breathe DNA Long molecule made from chains of four different types of chemical (represented by the letters ACGT) that can be used to create a code to build each part of the body Stands for deoxyribonucleic acid dominant Used to describe an allele of a gene that shows up in your characteristics over a recessive allele glands Group of cells with the job of making and releasing specific hormones and other substances emotions Inner feelings that affect the brain and body These include happiness and fear hemoglobin Red-brown colored protein found in red blood cells empathy Ability to share in and understand another’s feelings enzyme Substance that speeds up chemical reactions in the body For example, digestive enzymes speed up digestion epidermis Thin, outer layer of your skin follicle Hole from which a hair grows genes Coded sections of DNA Genes control the way your body works and develops hormones Chemical messengers that are created in glands and organs They travel through your blood to tell another body part what to joint Connection between two bones keratin Tough, waterproof protein found inside dead cells that make up the epidermis, hair, and nails ligament Slightly stretchy, connective tissue that holds bones together 139 meninges Three flat layers of tissue that are located between your brain and skull nutrients Basic chemicals that make up food Used to help the body grow, move, and repair itself protein Particular type of complex organic building block made from amino acids molecule Chemical unit that is made up of atoms organ Group of tissues that form a body part, such as your lungs reflex Automatic body movement, such as blinking organelle Small, floating, living machines that have different roles in each cell For example, mitochondria release energy to power the cell regulate Control a process For example, hormones help you to regulate many things, such as your growth MRI Type of body scan that uses magnets MRI stands for magnetic resonance imaging mucus Thick, slimy fluid It is produced in the mouth, throat, intestines, and nose nerves Bundles of fibers that carry electrical signals around the body neuron Another word for a nerve cell Neurons produce and pass electrical signals to other neurons and body parts nucleus Central part of a cell that contains the chromosomes organism Living thing Types of organism include animals, bacteria, and plants ossicles Three tiny bones in your middle ear They are called the malleus, incus, and stapes oxygen One of the gases in the air Humans need to breathe in oxygen to live particles Very tiny building blocks that make up all things respiration Process by which a living thing makes energy sensor Type of cell that helps you feel things that relate to your senses, such as taste and touch sphincter Ring of muscle that closes or opens to control the passage of material through it For example, the sphincters in your bladder control the passage of your pee spinal cord Large bundle of nerves in your spine that connects the brain to nerve cells in your body stem cells Cells that can become other types of cell tissue Group of cells that the same job, such as muscle tissue transplant Organ from one body used to replace an affected organ in another body vertebrae Bones that link together to form your spine 140 Index 2-D images 115 3-D images 63, 118–19 A adenine 19 ADHD 103 adrenal glands 25 aging 69, 104–5 air 9, 40–1, 74, 75, 76 air pressure 88–9 alertness 108 alleles 20 alveoli 41 amygdala 42 animals breathing 74 hair 85 hearing 60 antibiotics 120–1 antibodies 116 aorta 35 appendix 11, 73 arms 31 arrector pili muscles 84 arteries 35 atria 34 autism 103 B babies bladder control 83 bones 29 burping 76 growth 78–9 stem cells 124, 125 water 107 baby teeth 46 bacillus bacteria 23 bacteria 22–3, 73, 87, 100 antibiotics 120–1 balance 64–5 beliefs 103 bending 65 biceps 31 bile 73 birth 79 bladder 82–3, 111 blind people 54 blinking 42 blood 14–15, 78 body temperature 66 circulation 34–5 digestion 72, 73 hormones 84 respiration 9, 41 waste 82 blood cells 14–15, 28, 124, 125 blood pressure 109, 123 blood sugar 25, 92 blood tests 122, 123 blood vessels 33, 35, 66, 67, 111 body clock 105, 108–9 body parts, prosthetic 130–1 bone marrow 28, 29, 124 bones 28–9 aging 104, 105 ears 60–1 exercise 95 joints 39, 58–9, 104, 105 muscles and movement 31, 58–9 ribs 36–7 spine 38–9 X-rays 114–15 Braille 54 brain 10, 32–3, 39 balance 64–5 bionic hands 130–1 bladder control 82 body clock 108, 109 body temperature 66–7 breathing 56–7 development 102–3 emotions 42–3 exercise 94 hearing 60–1 hormones 24 left and right sides 43 memory 70–1 movement 31 sleep 109 taste and smell 49 thirst 106 touch 50, 54–5 vision 63 brain stem 56 breathing 40–1, 56–7, 123 underwater 74–5 brittle bones 105 burping 76–7 C calcium 105 calories 94 cameras 128, 139 canine teeth 46, 47 capsule endoscopes 128 capsules 22 carbohydrates 93 carbon dioxide 9, 15, 40–1, 56, 57, 74, 93 cardiac muscles 31 cartilage 29, 36, 37, 38, 59, 60, 69, 105 cells 8–9, 12–13, 78 aging 104 bacteria 22–3, 121 building and repairing 92 dead 44, 45, 80, 81 division 124 DNA 16–19 intestine 12 muscle 12 respiration 93 stem cells 124–5 water 106, 107 cementum 47 center of gravity 65 cerebrospinal fluid (CSF) 32, 33 chambers, heart 34 chemical signals 11, 24–5, 84, 94, 98, 110, 111 chromosomes 16, 17, 23 clothing, white 127 coccus bacteria 23 141 coccyx bone 39 cochlea 61 collagen 105 compact bone 28 computer tomography (CT) scans 119 computers 118, 119 connective tissue 59 coordination 109 counseling 97 COVID-19 117 crabs 75 cramp 51 crowns (teeth) 47 crying 99 CT scans 119 cytokinesis 124 cytoplasm 13, 23 cytosine 19 D da Vinci Surgical System 128, 129 dairy products 92 dehydration 83 dentine 47 dentures 131 dermis 81 diagnosis 122–3 diaphragm 56, 57 diet 32, 92–3 digestion 72–3, 77, 110 digestive system 12, 22, 72–3, 128 disks 38, 39, 69 DNA 8, 13, 16–17, 18–19, 20, 23, 124 Down syndrome 102 drinking 83, 106 dyslexia 102 dyspraxia 102 E eardrums 61, 88 ears 37, 60–1, 64, 105 popping 88–9 eating 46–9, 72–3, 92–3, 97 eggs 9, 78 elbows 80 electrical signals 31, 38, 39, 55, 61, 63, 64, 70–1, 100, 111 embryos 78, 124 emotions 42–3, 86, 96–9 empathy 99 enamel 21, 46, 47 energy 40–1, 92–3, 94, 95, 105 enzymes 72, 73 epidermis 80, 81 epinephrine 25, 84 episodic memory 70 eructation 76 esophagus 72, 77 eustachian tubes 88, 89 exercise 94–5 exoskeletons, robot 128 eyebrows 86–7 eyelids 55 eyes 10, 62–3, 64, 86, 105 F facial expressions 84 family rules/beliefs 103 family tree 20 fat 92, 94, 107 fathers 9, 17, 20–1, 78 fear 25, 42, 43, 84, 85, 110–11 feet 50–1, 55, 80 femur 28–9 fertilization 78 fetus 79 fiber 93 fight or flight response 110 fingers 54–5 flagella 22 Fleming, Alexander 120 floating ribs 36 flushing 67 food 12, 94, 97 body temperature 66, 67 diet 32, 92–3 digestion 72–3, 77 friends 96 frowning 86 fungi 120 G gallbladder 73 gastric juices 72 gene editing 125 genes 16–17, 18–19, 20–1, 78 germs 10, 14, 22, 100–1 gills 74, 75 glands 24 glucose 92 gluteus maximus 30–1 goose bumps 84–5 gravity 64, 65, 68, 69 guanine 19 gums 47 H hair 45, 108 eyebrows 87 goose bumps 84–5 gray 105 hair follicles 45, 54, 84 hands 54, 110 bionic 130–1 washing 101 happiness 43, 96, 98–9 health diet 92–3 exercise 94–5 hearing 60–1, 105 heart 10, 34–5, 37, 57, 78 cardiac muscles 31 exercise 94–95 racing 110 pacemakers 131 heat 66 height 68–9 hemoglobin 15 hippocampus 43 hips 59, 104 hormones 11, 24–5, 67, 84, 109 hydrochloric acid 77 hypothalamus 42, 67 I illness bacteria 22, 121 diagnosis 100, 122–3 viruses 100, 116–17 immunity 117 implicit memory 70 incisors 47 incus 60, 61 inheritance 18, 19, 20–1 inner ear 61 intestine cells 12 intestines, small and large 57, 72–3 iris 62–3 iron 14, 15 J jawbone 47 Jenner, Edward 117 joints 39, 58–9, 105 repairing/replacing 104 jumping 58–9, 68 142 body temperature 67 cardiac 31 cramp 51 exercise 94, 95 eyes 62–3 movement 30–1, 42, 58–9 skeletal 31 smooth 31 sphincter 72, 76, 83, 111 N K keratin 44–5, 80 keyhole surgery 128 kidneys 11, 82–3, 120 knees 58, 59 L laughter 98 learning 70 legs 30, 51, 58–9 prosthetic 130–1 lifestyle 17, 19, 21 ligaments 36, 38, 39, 59 light 62–3 lips 55 liver 10, 66, 73, 130 lungs 9, 34, 35, 37, 79, 94, 95, 123 breathing 41, 56–7, 74 M Magnetic resonance imaging (MRI) 118–19 malleus 60, 61 Maslow, Abraham 98 Meissner’s corpuscle 54, 55 melatonin 11, 24, 109 membranes, cell 12, 13, 22 membranes (meninges) 32 memory 43, 70–1 meninges 32 mental health 96–7 Merkel’s disk 54, 55 middle ear 61, 88, 89 mindfulness 97 minerals 93, 105 mitochondria 12, 13 mitosis 124 molars 46, 47 mollusks, aquatic 75 mothers 9, 17, 20–1, 78, 79 mouth 22, 41 movement 30–1, 42, 58–9, 65, 92, 93 MRI scans 118–19 mucus 49 muscle cells 12, 30, 107 muscles 69, 71 aging 105 arrector pili 84 balance 64 bladder 82 nails 44–5 nasal cavity 56 nerves 38, 50–1, 54, 55, 64, 65 neurons 70–1 nose 20, 37, 41, 49 nucleus 8, 12, 13, 16 numbness 50–1 nutrients 12, 32, 72, 73, 126 O old age 69 operations robotic 128–9 transplant 130–1 organ systems organelles 12 organs 9, 10–11, 79, 125 scanning 119 transplants 130 ossicles 60, 61 outer ear 60 oxygen 9, 14, 15, 35, 40–1, 57, 74, 75, 78, 79, 93 P pacemakers 131 pancreas 25 papillae 49 pee 82–3, 106, 111 penicillin 120–1 periosteum 28 personality 19, 102 photosynthesis 40 pineal gland 11, 24 pins and needles 51 pituitary gland 24 placenta 79 plants 40–1 plasma 14 platelets 14, 15, 125 poop 23, 73, 93, 122 potty training 83 prefrontal cortex 42 pregnancy 78–9 premolars 46, 47 pressure sensors 65 procedural memory 70–1 prosthetic body parts 130–1 proteins 92 pulmonary artery 35 pulmonary vein 35 pupils 62–3, 110 pyramid of needs 98 R radiation 114 radio waves 118, 119 receptors 48, 54, 55, 61, 62, 63, 65, 67, 82 red blood cells 14, 15, 29, 125 reflexes 42 relationships 96, 102 remote control 128 respiration 40–1, 93 respiratory system 8, ribosomes 23 ribs/rib cage 36–7, 57 robotic arms 128, 129 robotic surgery 128–9 Röntgen, Wilhelm 114 roots (teeth) 47 143 S sadness 97, 98–9 saliva 49, 72, 106 scanners 118–19 semantic memory 70 sensors 49, 50, 54, 61, 62, 65 sensory organs 64 shivering 67 skeletal muscles 31 skeleton 36–9, 58–9 skin 10–11, 105 body temperature 66 goose bumps 84–5 making new 80–1 nails 44, 45 sun protection 126–7 touch 50, 54–5, 65, 66 skin cancer 127 skin cells 80–1 skull 29, 32–3 sleep 97, 105, 108–9 smallpox 117 smell 49 smooth muscles 31 soap 100–1 soft tissue 8, 114, 115 soles 55, 80 sound waves 60 sperm 9, 78 sphincter muscles 72, 76, 83, 111 spinal cord 32, 33, 38 spinal nerves 39 spine 36, 38–9, 68, 69 spirella 22 spleen 11 spongy bone 29 standing 65 stapes 60, 61 stem cells 105, 124–5 sternum 37 stethoscopes 123 stomach 25, 72, 76, 77, 110 stomata 40 sugar 40–1, 49, 92 sunburn 127 sunglasses 126 sunlight 40 sunscreen 126–7 superbugs 120 swabs 122 swallowing 72, 88 sweat 106, 110 sweat glands 81, 86, 110 sweating 67, 87 synovial fluid 59 T taste 48–9 teeth 21, 46–7, 115 temperature 24, 25, 42, 65, 66–7, 84–5, 87, 109, 121, 122 tendons 30, 31, 58 tests 122–3 thirst 106 thymine 19 thymus gland 24 thyroid gland 24, 67 thyroxine 67 tissues 8, 78, 115 tongues 48–9 touch 54–5, 65 trachea 41, 57 transient paresthesia 51 transplant operations 130–1 triceps 31 twins, identical 18–19 twins, nonidentical 18 U ultrasound 119 ultraviolet (UV) light 100, 126, 127 umbilical cord 78, 79, 125 unhappiness 97 urethra 83 urine 82–3, 106, 111, 122 urobilin 83 V vaccinations 116–17 vacuoles 13 valves 34 veins 14, 35 vena cava, inferior and superior 34 ventricles 33, 35 vertebrae 38, 39, 69 vestibulocochlear nerve 61 vibrations 60, 61, 77 viruses 23, 100, 116–17 vision 62–3, 105 vitamin D 126 vitamins 93 W walls, cell 22 walls, heart 34 washing 100–1 waste 72, 73, 78, 82–3, 93 water 32, 72, 73, 93, 106–7 breathing under 74–5 white blood cells 14, 24, 33, 116, 125 womb 78, 79 working memory 70 wrinkles 105 XY X-rays 114–15 yawning 88 Acknowledgments DORLING KINDERSLEY would like to thank: Polly Goodman for proofreading; Helen Peters for the index; Sally Beets, Jolyon Goddard, Marie Greenwood, and Dawn Sirett for editorial assistance; and Niharika Prabhakar and Roohi Sehgal for editorial support Consultant Darrin Lunde, National Museum of Natural History, Smithsonian Institution Smithsonian Enterprises Kealy Gordon Product Development Manager Janet Archer DMM Ecom and D-to-C Jill Corcoran Director, Licensed Publishing Carol LeBlanc President The publisher would like to thank the following for their kind permission to reproduce their photographs: (Key: a-above; b-below/bottom; c-center; f-far; l-left; r-right; t-top) Getty Images / iStock: akesak (br) Alamy Stock Photo: Alexandr Mitiuc (cr) Dreamstime.com: Igor Zakharevich (tr) Dreamstime.com: Okea (cb) Robert Steiner MRI Unit, Imperial College London: (tr) Science Photo Library: Dr Torsten Wittmann 6–7 Getty Images / iStock: kali9 (tc) Science Photo Library: Dr Torsten Wittmann (b) Dreamstime.com: Sebastian Kaulitzki (clb); Mopic (cb) 10 Dreamstime.com: Srckomkrit (clb) 11 Dreamstime.com: Rajcreationzs (cb); 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Zakharevich tc; Spine: Dreamstime.com: Igor Zakharevich b All other images © Dorling Kindersley For further information see: www.dkimages.com ... and pulls your body into a different shape If you lift up your leg, you use your gluteus maximus to pull your leg back into a straight position Gluteus maximus How muscles move my body? Tricep... instructions that make you who you are Each organ in your body has an important job to do, and your blood helps to supply them with everything they need to work 8 BODY BASICS What’s my body made of?... the body Do genes control who I am? Genes control many things, even parts of your personality, but your life experiences also shape your thoughts and who you are What you eat and the exercise you