Puberty by Jillian Powell Read Free Book Online

E-book published in 2012 by Encyclopædia Britannica, Inc., in association with Arcturus
Publishing Limited, 26/27 Bickels Yard, 151-153 Bermondsey Street, London SE1 3HA.
Britannica, Encyclopædia Britannica, and the Thistle logo are registered trademarks of
Encyclopædia Britannica, Inc.
ISBN 978-1-61535659-1 (e-book)
This edition first published in 2010 by Arcturus Publishing Distributed by Black Rabbit Books
P.O. Box 3263
Mankato, Minnesota 56002
Copyright © 2010 Arcturus Publishing Limited The right of Jillian Powell to be identified as the author of this work has been asserted by
her in accordance with the Copyright, Designs, and Patents Act 1988.
All rights reserved
Planned and produced by Discovery Books Ltd.
www.discoverybooks.net
Managing editor for Discovery Books: Rachel Tisdale
Editors: Amy Bauman and Juliet Mozley
Designer: D. R. ink
Consultant: Xanthe Fry, School Counselor and Educational Consultant
Picture researcher: Tamsin Osler Library of Congress Cataloging-in-Publication Data Powell, Jillian.
Puberty / Jillian Powell.
p. cm. -- (Teen FAQ)
Includes index.
1. Puberty--Juvenile literature. I. Title.
QP84.4.P69 2011
612.6′61--dc22
    2010012715
Picture Credits
Bubbles Photo Library: 6, 37 (Chris Rout). Corbis: cover (Mark Seelen), 11 (James Jeynse), 15 (amanaimages), 16 (Josef Lindau), 17 (Image Source), 21 (Pinto), 42 (Erik Isakson), 43 (Kate Mitchell). Discovery Photo Library: 9 (Chris Fairclough). Getty Images: 19 (Tetra Images), 25 (Datacraft), 26 (David Grossman/Workbook Stock), 30 (John Giustina/Iconica). Istockphoto.com: 23 & 45 (Joselito Briones), 34 (Galina Barskaya), 38 (VMJones), 41 (Linda Kloosterhof). Science Photo Library: 22 (Dr. P. Marazzi). Shutterstock: 7 (Monkey Business Images), 9 right (Lev Olkha), 13 (Magdalena Zurawska), 14 (Monkey Business Images), 29 (Yuri Arcurs), 35 (kojoku), 40 (Martin Novak).
Every attempt has been made to clear copyright. Should there be any inadvertent omission, please apply to the copyright holder for rectification.
SL001460US
Supplier 03, Date 0510

1 What’s puberty about?
    You do your fastest growing during the first year of your life, and then during puberty. About two years before you notice any physical changes, your brain is getting you ready for puberty. Beginning as early as age eight in girls—and two years later, on average, in boys—the brain sends signals for hormonal changes that stimulate puberty. This is the period of physical and sexual development as your body matures into that of an adult.
    The first sign of puberty occurs on average at age 11 in girls, with menstruation following about two years later. Signs in boys generally start about two years later, although in some cases puberty may not begin until about the age of 15.
    WHAT ARE HORMONES?
Hormones are chemicals made by one part of your body (glands) that are carried around in the bloodstream to act on different parts of the body. Hormones work by triggering changes in “target cells,” which have special hormone receptors. For example, the pituitary gland makes growth hormones that stimulate the bones in your feet, arms and legs to grow longer.

The chemical changes that trigger puberty begin happening while you are asleep.
    Night action
    No one knows why, but puberty begins when you are asleep! Cells in the brain begin sending chemical signals in the form of hormones in your bloodstream. They begin the changes we call puberty.
    Growth spurt
    Puberty triggers a “growth spurt,” and you’re suddenly growing bigger and taller. On average, a young person’s height increases by around 10 inches (25 cm) during puberty. Many find their arms and legs grow first, making themlook and feel a bit “gangly” or clumsy until the rest of the body catches up. You may find you quickly outgrow clothes and shoes and you can feel tired and need more sleep as your body uses energy for growing. Girls keep on growing until they are around 17 years old, and some boys continue growing until they