人体图文解释 英文彩色高请原版

Eye Wonder Open your eyes to a world of discovery Eye Wonder Open your eyes to a world of discovery Eye Wonder First American Edition, 2003 03 04 05 10 9 8 7 6 5 4 3 2 1 Published in the United States by DK Publishing, Inc 375 Hudson Street New York, New York 10014 Copyright © 2003 Dorling Kindersley Limited All rights reserved under International and Pan-American Copyright Conventions. 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 written permission of the copyright owner. Published in Great Britain by Dorling Kindersley Limited. Library of Congress Cataloguing-in-Publication Data Bingham, Caroline, 1962- Body / by Caroline Bingham ; consultant, Daniel Carter. p. cm. -- (Eye wonder) Includes index. Summary: A brief introduction to the human body, including some facts about sleep ISBN 0-7894-9044-7 1. Body, Human--Juvenile literature. [1. Body, Human. 2. Sleep.] 1. Carter, Daniel. II. Title. III. Series. QM27 .B564 2003 306.4--dc21 2002009547 ISBN 0-7894-9044-7 Color reproduction by Colourscan, Singapore Printed and bound in Italy by L.E.G.O. See our product line at www.dk.com Written and edited by Caroline Bingham Designed by Helen Melville Managing editor Sue Leonard Managing art editor Cathy Chesson Category publisher Mary Ling US editor Christine Heilman Jacket design Chris Drew Picture researcher Marie Osborn Production Shivani Pandey DTP Designer Almudena Díaz Consultant Daniel Carter Thanks to Penny Arlon for editorial assistance 4-5 Everyone looks different... 6-7 ...but we are all alike inside 8-9 Babies and belly buttons 10-11 Life in a bag 12-13 A bag of bones 14-15 Hairy stuff 16-17 Move that body 18-19 Pump that blood! 20-21 A circular tale 22-23 Puff, puff 24-25 Attack of the bugs 26-27 Let’s talk LONDON, NEW YORK, MUNICH, MELBOURNE, and DELHI Contents 28-29 Brainpower 30-31 Touch 32-33 Listen up! 34-35 Eye, eye 36-37 Smelly stuff 38-39 Fun with taste 40-41 Take a bite 42-43 From food to poo 44-45 Sleep tight 46-47 Glossary 48 Index and acknowledgments Tall, short, plump, thin, blond, dark... Even though we have two eyes, a nose, two arms, and so on, we still all look so different that we can recognize each person we know without getting anyone confused. Everyone looks different... Hu man beings are different in all so rts of ways. It is thought 4 There are slight differences between the left- and right- hand sides of your face. •The average human body contains enough iron to make a nail 1 in (2.5 cm) long. •Brown or black skin has more of a pigment called melanin in it than white skin. •You inherit certain features (such as hair color or body shape) from your parents. Body facts that more tha n 6,500 lan guages are spoken througho ut the world. What about twins? Only identical twins look alike, and that is because they develop at the same time, from one egg that has split into two. Identical twins are always the same sex. 5 ...but The lungs make up a part of the respiratory system. Building blocks A number of organs may make up each body system. For example, the stomach, liver, intestines, gallbladder, and pancreas make up your digestive system. 6 Yo ur bo dy is a co lle ct io n of sys tem s, e ach of wh ich has a job to do. Stomach Liver Many of your organs are packed neatly into your torso (the part without the head and limbs). All bodies are made up of organs. Skin is an organ. It is wrapped around a framework of bones and other organs such as the heart, the brain, and the lungs. we are all alike inside It would take about 200 of your cells to cover a period. Cell Nucleus A TALL STORY The tallest man ever recorded, Robert Wadlow, grew to 8’11” (272 cm). He was born in the US in 1918, and died in 1940. He was known as the Gentle Giant. He grew so big because too much growth hormone was released into his body. What does an organ do? Organs work to keep you alive, and each does a different job. Organs work together to make up systems, such as the muscular system and the circulatory system. Made of tissue Organs are made up of tissue, which is made of groups of similar cells. These magnified cells are from the lungs. Different cells Cells are different depending on the organ they are a part of – skin cells, for example, are different from bone cells. Most cells have a nucleus – the control center. 7 Yo ur bod y has about 50,000 billion cells. 8 Babies and belly buttons •At just eight weeks, the fetus can be recognized as human – although it is shorter than your little finger. •Fingernails begin to form when the fetus is about ten weeks old. •A fetus can get hiccups. Baby facts They can hear you! A baby can hear noises from around its mother’s tummy – it can hear you talking or laughing, and it will recognize your voice. A race to the egg Millions of sperm swim toward the mother’s egg to fertilize it, though only about one hundred get near it. Just one sperm fertilizes it. Legs here, arms there... After the egg has been fertilized, it begins to divide, becoming a ball of cells. It is full of instructions for what the baby will look like. We all begin life inside our mother as a tiny egg. This develops after it is joined, or fertilized, by a sperm from the father. Most babies spend about 40 weeks growing in their mother’s tummy. How does it breathe? The fetus cannot eat or breathe until birth, so it gets food and oxygen from its mother through a special cord. At birth this cord is cut, and shrivels away to leave the belly button. The fetus is protected in a sac of fluid. The cord that attaches a baby to its mother is called the umbilical cord. 10 Your skin is a fabulous bag for your body. It’s stretchy and waterproof. It helps to control your body’s temperature, and it protects you from germs. Life in a bag A unique print Everybody has a unique set of fingerprints, but there are three main types: arch, loop, and whorl. Skin facts •About 50,000 tiny flakes of dead skin drop off your body every minute! •Millions of microscopic dust mites live in your bed, gobbling up the skin flakes that fall off you. In m ost places, your skin is about 1⁄1 6 in (2m m) th ick . 11 What’s underneath? Skin contains sweat glands, hair follicles, nerve endings, and tiny blood vessels called capillaries. Underneath, there’s a layer of fat. My feet are wrinkly! Spend a long time swimming and the thicker skin on your feet and hands will begin to wrinkle because water has soaked into it. The extra water makes it pucker up. Sweat it off You sweat to keep cool – but did you know that in a fingernail-sized patch of skin there are between 100 and 600 sweat glands? Skin alert...cure that cut! Cut yourself and a lot of activity in the surrounding skin causes the blood to clot. The resulting scab stops dirt and germs from getting in. Flakes of dead skin fall off your body all the time. Cells lock together to provide a waterproof layer. What’s a bruise? Bruises are caused by damage to the tiny blood capillaries that run just under the skin’s surface. If broken by a heavy knock, they bleed into the surrounding area. A bag of bones Bones protect your internal organs from damage and act as a frame to hold you up. They are linked together by muscles and tendons to make up your skeleton. Bony hands More than a quarter of your bones are in your hands. An adult has 27 bones in each hand. The number of bones in the hands makes them very flexible. Extra bones A baby’s skeleton is largely cartilage, the stuff that holds your nose out and makes it bendy. 12 • Compared to a steel bar of the same weight, a bone is far stronger. • You have the same number of neck bones as a giraffe. • Bones need calcium from foods like milk and cheese to make them hard. Bone facts Hidden support If you cut through a femur, or thigh bone, you’d see that the inside is a spongy honeycomb. This makes it strong, but light. Joints A joint is the place where two bones meet. This is a hip joint, which is a ball-and- socket joint. It gives lots of movement. It’s broken! If you break a bone, an X-ray shows the doctor what is going on beneath the skin. Bones are living tissue, and will usually mend, with rest and support, in about 6–8 weeks. The rounded end of the femur fits snugly into the pelvis. Pelvis Femur Y our bones are fullofblood vessels, nerves, an d cells. This X-ray shows two broken legs. An adult skeleton contains 206 bones. 13 14 Hairy stuff Your hair and nails are made of the same thing. It’s called keratin, and most of it is dead. In fact, your hair and nails are only alive at the roots. That’s why it doesn’t hurt to cut your hair or trim your nails. A hairy tale Hair grows over most of your body. The thickest is on your head, where you have between 100,000 and 150,000 hairs! This close-up of eyelash hairs shows how they grow from follicles in the skin. Each hair is made of overlapping plates of keratin. 15 Are you right-handed? If so, the nails on this hand will grow faster than those on the left. This is controlled by the brain. Head lice Head lice love to cling to hair, suck our blood, and lay their eggs. Get rid of them with special shampoo. Scratchy head? If your head itches, you may have head lice. You can see their eggs as tiny white spots in the hair above your ear. Fi ng er na ils gr ow fou r ti mes faste r than toenails. A female head louse will lay 50–150 eggs. Like hair, your nails are made of millions of overlapping plates of keratin. 16 Step forward and you’ll use about 200 muscles. You have at least 600 muscles, and they are responsible for every movement you make, from jumping to blinking to breathing. Bend your arm Try tensing the muscle in your upper arm, your biceps. Can you feel it getting harder? A closer look A muscle is made up of bundles of tiny fibers. Each fiber is incredibly thin – much thinner than a hair. The biceps has contracted. The triceps has relaxed. MUSCLE MOUSE The word “muscle” comes from the ancient Romans, who thought that muscle movements under the skin looked just like a mouse running around. Their word for mouse was musculus. Move that body 17 How do they work? Muscles can only pull, so they work in pairs. In your arm, the biceps pulls by contracting to bend the arm and the triceps pulls to straighten it. Make a face! Your face is full of muscles. Incredibly, you use 17 of these muscles to smile. However, you use about 40 muscles to frown! The muscles in our face allow us to make about 10,000 different facial expressions! •Your muscles make up 40 percent of your body’s weight. •Help your muscles grow big and strong by eating lots of protein. That means lots of eggs, meat, cheese, and beans. •Muscles can contract to one-third of their size. Muscle factsAll joined up Many muscles are joined to the ends of the bones they control by stringy cords called tendons. A s a m us cl e co nt ra ct s, it ge ts sh or te r an d ha rd er . A s a m us cl e re la xe s, it ge ts lo ng er an d so fte r. Clench your fist and you can see a tendon working under the skin of your wrist. 18 Can you feel your heart beat? This amazing muscle never gets tired, even though it opens and closes about 100,000 times a day, every day, throughout your life. Pump that blood! Where is it? Your heart is protected by your rib cage. It is slightly to the left of your chest. A one-way system Your heart beats to push blood around your body. Four valves ensure that the blood always goes the same way. Speed up! Run and your heart beats faster. This gets more oxygen to your muscles. Held with string Heart strings are tiny cords that stop the valves from turning inside out when they close. A heart has four cham bers. 19 What is blood? Blood is made up of a watery liquid called plasma, red cells, white cells, and fragments of cells called platelets. A tangled web This is what happens when your blood clots because of a cut. The red cells are caught in a mesh of fibers. They die and stop blood from flowing out. Red blood cells Red blood cells make up about 44 percent of your blood. Millions are made and destroyed every second. Fighting infection White blood cells and platelets make up less than one percent of blood. They fight germs. •At rest, a child’s heart beats about 85 times a minute. •A drop of blood contains approximately 250 million red cells, 275,000 white cells, and 16 million platelets. •A blood cell goes around your body and back through your heart more than 1,000 times each day. Heart/blood facts Re d c ells are d oughnut-shaped. Plasma makes up about 55 percent of your blood. The mesh forms very rapidly. Your heart pumps blood around your body through arteries and veins. Arteries carry blood away from the heart. Veins carry blood toward the heart. A change of color As blood travels through the lungs, it picks up oxygen. This makes it brighter in color. As it releases oxygen around the body, it grows darker. A ONE-WAY SYSTEM Almost 400 years ago, an English doctor named William Harvey discovered that blood circulates one way around the body, pumped by the heart. Harvey drew detailed diagrams of arteries and veins to show what he meant and published his results in 1628. A circular tale Most to the brainYour brain needs a constant supply of oxygen-rich blood. It is so important that it gets 20 percent of your body’s blood supply. Smaller and smaller Arteries and veins become a branching network of capillaries. The capillary walls are so thin that gases, nutrients, and waste products pass easily through. A close-up of an artery This cross-section of an artery is magnified so much that the red blood cells can be seen. Arteries usually have thicker walls than veins. Feel the beat You can feel your heart’s beat as it sends a pulse through the artery in your wrist. Hold your index finger against the inside of your wrist. The regular beat is the surge of pressure that occurs when the heart contracts. Oxygen-rich blood Oxygen- poor blood Most veins (shown in blue) carry blood that contains carbon dioxide, a waste gas. A blood cell travels around your body in about 60 seconds. Yo ur fin ge rs an d to es ar e th e co ol es t p ar ts of yo ur bo dy . A n ad ul t’s bl oo d ve ss el s s tr et ch 99 ,4 00 m ile s ( 16 0,0 00 k m) . Your brain is the hottest part of your body. Most arteries (shown in red) carry blood rich with oxygen and food. Blood supply to the brain. Kidney Lung Stomach Lung Brain Liver Kidney 22 Believe it or not, you take about 23,000 breaths each day. With every breath, you take in oxygen, which you need to stay alive, and you breathe out a gas called carbon dioxide, which your body doesn’t need. Puff, puff A wind tunnel Air travels down your windpipe, or trachea, to get to your lungs. In this photograph, you can see the rings of cartilage that hold the trachea open. Taking out the oxygen The air tubes (shown red) get smaller and smaller until they end in millions of tiny air sacs called alveoli. Here, oxygen is taken into your blood. Air passes down your windpipe, or trachea, and into your two lungs. Air tube These spaces are air sacs called alveoli. 23 Blowing bubbles We can only store oxygen for a short time in our lungs. Also, unlike fish, we have no gills to remove oxygen from water. So we cannot stay underwater without an air supply. WHY DO I GET HICCUPS? Hiccups happen when the muscle that helps to move air in and out of your lungs, your diaphragm, jerks uncontrollably. Nobody really knows why they happen, but there are lots of suggestions for stopping them. Try breathing into a paper bag...or ask a friend to scare you...or (yummy!) put sugar under your tongue. •Stethoscopes, which doctors use to check breathing, were invented in 1816. •You breathe faster during and after exercise to draw more oxygen into your body. •Your left lung is smaller than your right lung to allow room for your heart. Lung facts There’s water, too Your breath contains water. If you breathe onto a cold surface, this water condenses into tiny droplets. That means it changes from a vapor into a liquid. The same thing happens on a cold day. 24 Bacteria can double their numbers in 20 minutes! Attack of the bugs Beastly bacteria Bacteria come in lots of funny shapes. Some even have tails! If a cut becomes infected (it will look red and swollen), that’s because bacteria have gotten in. What are germs? Germs fall into two main groups: bacteria and viruses. Your body is good at keeping them out, but they are clever at finding ways in. Vile viruses Have you had chicken pox? It’s caused by a virus. So is the common cold. Viruses are tiny – far smaller than bacteria. Everywhere you go, you are surrounded by nasty germs, and many of them want to live inside your body. After all, it makes a comfy home. The problem is, they can make you ill. 25 Outside help Can you remember having an injection called a vaccination? These are weak or dead germs, or the poisons produced by germs. They won’t harm you, but help your body to fight an illness. Millions of bacteria live on your ski n. Fighting back The good news is that your body makes things called white blood cells that can kill germs. The white blood cell pictured above is gobbling up a germ. EARLY MEDICINE Thousands of years ago, people believed that illness was a punishment from the gods. It was not until the 5th century BC, some 2,400 years ago, that the Greek doctor Hippocrates told people that their surroundings, not magic, caused disease. He is known as “the father of medicine.” There are many ways of “talking,” and not all of them are with your lips. The look on your face and the way you stand tell people a lot about what you are thinking. Let’s talk Making a word You make sounds as you breathe out over your voice box, or larynx. Your tongue, lips, and teeth change the sounds into words. h i d e h u g 26 I need it now! Babies can’t talk, so they cry to let you know that they want something. From early on, they also communicate by eye contact and facial expression. w aa aa aa aaaaaaaa aaa aa aa g i g g l e w h i s p er c r y What do you think? Body language can say a lot about the way you feel. Throw your arms in the air and people know you’re excited. Are these children sad? 27 s h o u tIt is thoughtthat at least 80 percent of communication is through body language. Sign language Signing is one way that people who are deaf can communicate. They use their hands to sign words and to spell letters. Some signed words use one hand, others use two. 28 Nerves in this girl’s fingers “tell” her muscles to grip the glass. •The brain needs oxygen to work properly. In fact, one- fifth of all the oxygen you breathe in goes to the brain. •The brain is 85% water. •The spinal cord stops growing when you are about five years old, having reached about 17 in (43 cm). Brain facts Step forward, touch something, talk, drink a glass of milk…everything you do is controlled by your brain. It’s a bit like a computer, but far more complicated – and it only weighs 2.9 lb (1.3 kg)! Brainpower How does it work? Your brain contains billions of nerve cells called neurons that carry signals to and from different parts of your body through your central nervous system. Use those senses! A simple drink requires a lot of brain power. Your eyes and fingers send messages about what you see and touch, while your nose and tongue help you to smell and taste the contents. To uc h Taste