The Best Goes On (Pathfinder Edition)

PLSAiTfcHeieFInNDcEeR EDITION

ON YOUR OWN

The BeaT Goes on

By Nancy Finton

PATHFINDSEcRieLnicfee
EDITION

It’s Time to
Explore on Your Own!

Good readers use multiple strategies as they
read on their own. Use the four key reading
comprehension strategies below:

1 Preview and
predict
• Look over the text.
• Form ideas about how the text is organized and what it says.
• C onfirm ideas about how the text is organized and what it says.

2 monitor and
fix up
• T hink about whether the text is making sense and how it relates to
what you know.
• I dentify comprehension problems and clear up the problems.

3 make
inferences
• Use what you know to figure out what is not said or shown directly.

4 sum
up
• Pull together the text’s big ideas.

Remember that you can choose different strategies at different
times to help you understand what you are reading.

The BeaT Goes on

PAthFinder edition

By Nancy Finton

Contents
2 the Beat Goes on
8 Getting Around
10 All Pumped Up
12 Concept Check

The BeaT

Your heart beats
100,000 times a daY.
each beat gives Your

bodY the oxYgen it

needs to survive.
but what happens
when the heart’s not
up to the job?

By Nancy Finton

Breathe. Within

seconds,the oxygen
you took in is cruising
throughout your body.

oxygen is carried by fast-
flowing rivers of blood. What
powers that bloodstream?
Feel the answer for yourself.
Just put your hand on your
chest. Beneath the skin and
bone lies a thumping,
pumping muscle—your heart.

2

Goes on

3

mightY muscle something’s missing!

Hearts work hard. Your heart beats about 90 Healthy hearts have four chambers, or sections.
times a minute. Each minute, in fact, this The two upper chambers, called atria, receive
powerhouse pumps your body’s entire supply blood from veins. The ventricles, or lower
of blood. That’s roughly 100,000 beats a day sections, pump blood into arteries.
and 2.5 billion over a lifetime. Each beat sends
oxygen and disease-fighting cells throughout That’s the plan, anyway. But Brian Whitlow’s
your body. life began differently. “I was born with only one
ventricle,” he says. Brian’s heart couldn’t pump
How does it happen? Next time you’re in blood to his lungs to get oxygen.
a pool, squeeze your hands together. Watch
the water shoot up. The heart does basically But Whitlow’s mother didn’t give up. Nor
the same thing. Each time it contracts, or did his doctors. When Brian was just a few
squeezes, blood squirts through tubes called weeks old, surgeons operated on him.
blood vessels.
“We can’t rebuild chambers that haven’t
Blood vessels come in three main types. grown,” says Dr. Daniel Bernstein, one of
Arteries carry blood away from the heart. They Whitlow’s childhood doctors. Instead, the
branch off into smaller and smaller tubes. The surgeons rearranged his blood vessels to bypass
smallest are called capillaries. Capillaries have the missing chamber.
thin walls. So oxygen and other materials can
travel from the blood into the cells where After the operation, Whitlow’s blood ran
they’re needed. Veins bring “used” blood back straight to his lungs. There it got oxygen, then
to the heart. flowed back to his heart. Whitlow’s single
ventricle then sent oxygen-rich blood gushing
broken hearts throughout his body.

Most kids have healthy hearts. Trouble usually That worked pretty well, Whitlow says. “I
comes years later, when parts of this pumping did all the normal things, including playing
“machine” wear out or get clogged with fat. Little League baseball.” Then things changed.

But there are hearts that need help sooner.
Some babies are born with heart problems.
Sometimes there’s a hole that blood leaks
through. At other times, parts of the heart
are incorrectly formed—or missing. Like
lifesaving mechanics, doctors step in to tune
up, repair, and even replace failing hearts.

take heart. ten years after his heart
transplant, Brian Whitlow plays goalie on his
college lacrosse team. He is a health major at
Chico state University in California. He plans
to work with kids in a teaching hospital.

4

Lifesavers. New devices, procedures, and
medicines have greatly reduced the risks of
heart surgery.

The Gift of Life The Waiting Game

By the time Whitlow turned 14, his patched-up Jessica Melore knows just how Brian Whitlow
heart was pretty tired. It was too weak to keep felt. She had a heart attack at 16. Her left
his body strong. “I had trouble running and ventricle was destroyed. Melore needed a new
had to nap all the time,” he remembers. heart. But would she get one in time?

Doctors recommended a heart transplant. Luckily, scientists have invented machines
That’s when a damaged body part gets replaced. that can help patients like Melore lead normal
“New” hearts come from people who agreed to lives during the long wait. Surgeons attached
donate them after death. “It’s a difficult thing a doughnut-size device to Melore’s heart.
when someone has to die in order for you to Powered by batteries, it did the pumping her
live,” says Whitlow. “But giving someone the left ventricle would have done.
gift of life is just plain wonderful.”
The artificial pump allowed Melore to finish
That gift took a while to arrive. Each year high school and get into college. Four days
about 35,000 people in this country need heart before graduation, she got word that doctors
transplants. There are only a small number of had found a new heart for her. Melore missed
replacements available. So Whitlow waited a graduating with her class but says, “The heart
month, then another, then another. was a good graduation gift.”

5

theY’ve got heart Second Chance. After her heart
transplant, Jessica Melore is an active
Back to Brian Whitlow. Altogether he waited student at Princeton University in new
13 months for a new heart. Finally doctors Jersey. she’s making the most of her
called with good news. There was a heart second chance at life.
available for him. Because hearts can’t live
long outside the body, Whitlow hurried to telling their stories
the hospital.
Today Brian Whitlow and Jessica Melore are
In the operating room, doctors hooked healthy college students. They have received
Whitlow to a machine that adds oxygen to a lot of attention. They’ve appeared on talk
blood while the heart isn’t working. Then shows and given interviews. Newspapers and
surgeons removed his damaged heart and magazines have written about them.
put the new heart in its place.
Both students hope their extraordinary
Whitlow recovered quickly. “I had my stories will inspire others. They’d like to see
surgery and started practice for high school more people arrange to have their organs
basketball the following October,” he says. But donated to others after death. “We really need
the recovery wasn’t easy. more organ donors,” Melore says. “It’s a little-
known issue.”
“I moved to a new high school after the
transplant,” Whitlow recalls. “I was taking Whitlow and Melore also want to help
medicine and gained 70 pounds. Kids made other kids who face obstacles. “Focus on the
fun of me, and that was hard. I had to keep positive things in your life,” Jessica tells young
telling myself they didn’t know my story.” audiences. “You can’t change what’s in the past,
so make the most of the future.”
Today Whitlow is on his college lacrosse
team. “My teammates tease me that I’m slow, wordWISE
because it takes me a little longer to warm up,”
he says. But now he knows that they’re only artery: tube carrying
teasing. “Last year, they voted me the Most blood away from the heart
Inspirational Player. That felt good.” atrium: upper heart chamber
(plural: atria)
blood vessel: tube that carries blood
capillary: smallest blood vessel in
the body
transplant: replacement of a person’s
damaged body part with a healthy part
from another person
vein: tube carrying blood to the heart
ventricle: lower heart chamber

6

a helpinG hearT

each year, thousands of people wait for heart transplants.
But only about 2,000 donor hearts become available.
so, for many people, machines are a life saver. one
machine helps a person’s own heart pump blood.
Another (below) is meant to replace a human heart.

Pump Tube

this machine has A large tube
two pumps. each carries the blood
has a motor that into and out of
pushes blood out each pump.
of the heart and
into the body.

Valve

Four valves
control the flow
of blood through
the heart and
into the body.

7

Your Circulatory System:

GETTING AROUND
Your body needs oxygen to survive. Getting oxygen to
all parts of your body is the job of the circulatory system.
It includes your heart, several quarts of blood, and more
than 96,561 kilometers (60,000 miles) of blood vessels.

Heart This fist-size muscle pumps nonstop. Each
heartbeat forces two ounces of blood into
the arteries. Some goes to the lungs to
pick up oxygen. The rest transports
oxygen to other parts of the body.

Lungs
These two organs take oxygen from
the air you breathe. Blood pumped to
the lungs then picks up the oxygen.

8

Left Atrium

Receives
oxygen–rich
blood from
the lungs

Left Ventricle

Pumps
oxygen–rich
blood
throughout
the body

Right Atrium Right Ventricle

Gets “used” blood Pumps blood to the lungs
from the body to pick up oxygen

Artery

Blood flows away from the heart through blood
vessels called arteries. They generally carry
oxygen–rich blood, which is bright red.

Vein

Blood flows back to the heart
through blood vessels called veins.
“Used” blood has a dark color.

9

ALL PUMPED UP

Each beat of your heart
pumps blood through
your body. That blood
is packed with oxygen.
When you exercise,
your body needs more
of this oxygen-rich blood
to keep going. So when
you’re active, your heart
really gets pumping.

10

How does exercise affect your heartbeat?
Find out by doing this easy experiment.
You may want to work with a partner.

 Predict

1 Will exercise make your heart beat more or less?

Test

2 Place two fingers on your wrist. Find a spot
where you feel a sort of thumping. That’s your
pulse. Each thump represents a heartbeat.

3 Count how many thumps you feel in 30 seconds.
Write the number down.

4 Now run in place as fast as you can for
two minutes.

5 As soon as you finish, place two fingers on your
wrist and count your pulse again. How many
times does it thump in 30 seconds now?
Conclude

6 Did your heart beat more or less after
you exercised?

7 Why did your heartbeat change when
you exercised?

11

Concept check The Human Heart

It is time to find out what you have
learned about the human heart.

1   How does your heart move
blood through your body?.

2   What is the difference between
arteries and veins?

3   What do the atria and
ventricles do?

4   How does a temporary artificial
heart help people survive?

5   How might stories about
heart transplants inspire
other people?

Index Acknowledgments
Grateful acknowledgment is given to the authors, artists, photographers,
artery  4, 6, 8–9, 12 museums, publishers, and agents for permission to reprint copyrighted material.
artificial heart  5, 7, 12 Every effort has been made to secure the appropriate permission. If any omissions
atrium (atria)  4, 6, 9, 12 have been made or if corrections are required, please contact the Publisher.
bloodstream  2
blood vessel  4, 6, 9 Photographic Credits
capillary  4, 6 Cover Bob Winsett/Corbis; 2-3 Corbis; 4 Tom Angel; 5 Pete Saloutos/Corbis;
chamber  4, 6 6 Jonathan Skow; 7 ABIOMED, Inc.; 10-11 Corbis Images.
heartbeat  8, 11
lung  4, 8–9 Illustrator Credits
oxygen  2, 4, 6, 8–10 8-9 Precision Graphics; 9 Amanda Bereny/Selavy Studios
transplant  4–7, 12
valve  7 Neither the Publisher nor the authors shall be liable for any damage that may
vein  4, 6, 9 be caused or sustained or result from conducting any of the activities in this
ventricle  4–6, 9, 12 publication without specifically following instructions, undertaking the activities
without proper supervision, or failing to comply with the cautions contained
herein.

Program Authors
Randy Bell, Ph.D., Associate Professor of Science Education, University of
Virginia, Charlottesville, Virginia; Malcolm B. Butler, Ph.D., Associate Professor
of Science Education, University of South Florida, St. Petersburg, Florida; Kathy
Cabe Trundle, Ph.D., Associate Professor of Early Childhood Science Education,
The Ohio State University, Columbus, Ohio; Judith Sweeney Lederman, Ph.D.,
Director of Teacher Education and Associate Professor of Science Education,
Department of Mathematics and Science Education, Illinois Institute of Technology,
Chicago, Illinois; David W. Moore, Ph.D., Professor of Education, College of
Teacher Education and Leadership, Arizona State University, Tempe, Arizona

The National Geographic Society
John M. Fahey, Jr., President & Chief Executive Officer
Gilbert M. Grosvenor, Chairman of the Board

Copyright © 2011 The Hampton-Brown Company, Inc., a wholly owned
subsidiary of the National Geographic Society, publishing under the imprints
National Geographic School Publishing and Hampton-Brown.

All rights reserved. No part of this book may be reproduced or transmitted in
any form or by any means, electronic or mechanical, including photocopying,
recording, or by an information storage and retrieval system, without permission
in writing from the Publisher.

National Geographic and the Yellow Border are registered trademarks of the
National Geographic Society.

National Geographic School Publishing
Hampton-Brown
www.NGSP.com

Printed in the USA.
RR Donnelley, Johnson City, TN

ISBN-13: 978-0-7362-7799-0

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Product #4E90219
PATHFINDER