DK - 1,000 Amazing Human Body Facts

Senior editor Ben Morgan Senior art editor Jacqui Swan Editors To m Booth, Joly on Goddard, Steve Setfor d US editor Jennette ElNaggar Designers Sunita Gahir , Laura Gar dner , Lauren Quinn, Peter Radclie, S amantha Richiardi, Mary Sandber g Illustrato rs Adam Benton, P eter Bull, Stuart Jackson-Carter , Arran Lewis Creative retouching Steve Crozier Picture re search co ordinator Sumita Khatwani Jacket design Stephanie Cheng Hui T an Jacket design dev elopment manager Sophia MTT Producer , p re-produc tion George Nimmo Senior produce r Meskerem Berh ane Managing art editor Owen Peyton Jones Managing editor Rachel Fo x Publisher Andrew Macintyr e Art director Karen Self Associate publishing director Liz Wheeler Publishing director Jonathan Metcalf Writers Jolyon Goddard , Dere k Harvey , To m Jackson, Andrea Mills, Ben Mor gan, Ginny Smith, Nicola T em ple First American Edition, 2021 Published in the United States by DK Publishing 1450 Broadway , S uite 801, New Yor k, NY 10018 Copyright 2021 Dorling Kindersley Limited DK, a Division of Pe nguin Random House LLC 21 22 23 24 25 10 9 8 7 6 5 4 3 2 1 001319151Aug/2021 All rights reserved. Without limiting the rights under the copyright reserved above, no part of this public ation may be reprod uced, stored in or intr oduced into a retrieval system, or transmitted, in any for m, or by an y means (electronic, mechanic al, p hotocopying, record ing, or otherwise), without the prior written permission of the copyright owner . Published in Great Britain by Dorling Kinder sley Limited A catalog re cord for this book is available from t he Library o f Congress. ISBN 978-0-7440-2884-3 DK books are available at special discounts when purchased in bulk for sales pr omotions, prem iums, fund-raisi ng, or educ ational use. Fo r details, c ontact: DK Publishing Special Markets, 1450 Broadway , S uite 801, New Yor k, NY 10018 SpecialSales@dk.com Printed and bound in China www. dk.com

TRANSPORT NETWORK How Long Are You r Blood V es sels? ............. How Small Are Blood Cells? .. How Much Blood Does You r Heart Pump? .......... How Big Are Y ou r Lungs? ... How Much Air Do You Breathe? .............. Heart, Blood, and Lungs Fa cts ................ BODY BASICS Whats Y ou r Body Made Of? ..................... How Many Cells Do Yo u Have? ................ Human Cells ................. How Many Organs Do Yo u Have? ................ Body Fa cts ................... OUTER BARRIER How Much Skin Do You Grow? ................... Skin Flakes .................. How Fa st Do Nails Grow? ..... How Many Hairs Do Yo u Have? ................ How Much Hair Do You Grow? ................... Eyelashes .................... Skin, Nail, and Hair F ac ts ..... MAKE A MOVE How Many Bones Do Yo u Have? ............... How Strong Ar e You r Bones? ............... Bone Cells ................ How Many Bones Are in Yo ur Skull? .............. How Many Bones Are in Yo ur Hands and Fe et? ...... How Do Y ou r Bones Heal? .... How Do Y ou r Joints W ork? .... How Many Muscles Are in Yo ur Fingers? ............. Muscle Cells ................ Skeleton and Muscle F ac ts ...

FUELING THE BODY How Much Fo od Do You Eat? ..................... How Many T ee th Do You Have? .................... Inside Y ou r T ee th ............. How Much Saliva Do You Make? ................... How Big Is Y ou r Stomach? .................. Gastric Pits .................. Where Does F ood Go? ........ Intestinal V illi ............... How Much Pee Do Yo u Pee? ................... Whats Y ou r Pee Made Of? .................... How Much W ater Is in Yo ur Body? ................ F ood and Digestion F acts .... SELF-DEFENSE How Many Microbes Live in Y ou r Body? .......... How Small Is a Bacterium? ................ How Fa r Does a Sneeze Tra vel? ........... Fol licle Mite .............. How Small Is a V irus? ...... Viruses ................... Why Do Fe et Smell? ........ Macrophage ............... Immune System F act s ..... THE CYCLE OF LIFE How Big Is a Baby? ......... Ultrasound Sc an ........... How Much DNA Do Yo u Have? .............. Reproduction F ac ts ......... YOUR OPERA TING SYSTEMS Skeleton ................... Muscles ................... Blood Circulation ........... Lymphatic Syste m ......... Digestion .................. Respira tion ................ Kidneys and Bladder ....... Reproduction .............. Nerves ..................... Endocrine System .......... Glossary ................... Index ...................... IN CONTROL How Fa st Is a Nerve Signal? ................ How Much Information Can Y ou r Brain Stor e? ...... Growth Hormone ........... Brain and Nerv e Fa cts ...... SUPER SENSES How Many Senses Do Yo u Have? .............. How Many Colors Can Y ou See? .............. Cones and Rods ............ How Do Illusions W ork? .... Otolith ..................... How Many Things Can Y ou Ta ste? ............. Whats the Smallest Bone in the Body? .......... Stereocilia ................. Senses Fa cts ..............

You r body is a giant jigsaw made of 30 trillion tiny pieces called cells. Neatly organized into tissues and organs, they work nonstop day and night to keep every part of you working. The inside of your body is normally hidden, but an X-ray camera can see right through you to create ghostly images of your bones and teeth.

YOUR BODY CONTA INS ABOUT 50 TEASPOONS OF SAL T. The human body is made of exactly the same chemical substances as all other living things, from eas to whales. The bu ilding blocks of all substances are elementspure chemica ls that cant be bro ken down into simpler ones. There are 118 chemical elements, but a mere six of these make up 99 perc ent of your body . The most abundant is oxygen, which make s up about 66 perce nt of your weight, and the second most abundant is carbon, which makes up 18.5 perc ent of your weight. WHAT S Y OUR THERES ENOUGH PHOSPHORUS IN THE HUMAN BODY TO MAKE 220 MA TC HES FAST F ACTS You r body contains a tiny amount of gold, but youd need 40,000 people (about one full football stadium) to make a single gold ring. Theres enough iron in your body to make a 3 in (7 cm) nail. Iron is needed to carry oxygen in your blood. Most of the elements in your body formed in the cores of dying stars. You r body contains enough carbon to make a diamond as big as a socc er ball.