In Uncle Al : In Uncle Al (9780307532572) (7 page)

TO BE CONTINUED IN ANDREW, JUDY, AND THUDD’S
NEXT EXCITING ADVENTURE:
ANDREW LOST
IN THE DESERT!

In stores January 2008

Thudd wanted to tell you more about big-eater cells and bones, but he was busy keeping Andrew and Judy from being munched by a parasite and lost in Uncle Al’s brain. Here’s what he wanted to say:

• There are many things outside of our bodies—bacteria, viruses, poisons, and tiny animals—that could hurt us if they got inside. We have immune systems made up of cells and molecules that patrol our bodies like armies to destroy dangerous things.
  

• All the cells in our bodies are marked with special molecules. This molecule code tells our
  immune system that these cells are part of us and should not be attacked.
  

  Blood cells have markers that say they belong to a group called a blood type. Your blood cells have markers for one of these blood types. If you got into a bad accident and needed blood, you would have to get it from someone with your blood type. If you received a different type of blood, your immune system would attack and destroy the strange cells. The attack would not only destroy the new blood cells, it could kill you, too.
  

• Macrophages have such big appetites, they actually eat until they die! After you scrape your knee or get a cut, do you ever see gooey yellow or white stuff around it? This is called pus. Pus is actually made up of dead white blood cells!
  

• Blood cells are red for the same reason that rusty iron is red. Iron turns red when it combines with the oxygen in the air. Blood cells
  have iron. Iron is what carries oxygen from our lungs to our bodies. When the iron in blood combines with oxygen, blood looks red.
  

• If you look at your wrists, you will probably see veins where your blood looks blue. Inside your veins, this blood is really deep red or purple. But it looks blue because you’re seeing it through your skin.
  

• Are you allergic to cats or pollen or bee stings? Poison ivy or peanuts? None of these things are dangerous all by themselves. Many people are not bothered by them at all.
  

  An allergy means that your immune system is confused about its enemies. It mistakes harmless stuff for dangerous stuff—and attacks. The problem is that the weapons of the immune system can cause lots of damage to your body, too—resulting in sneezing, itching, swelling, fevers, and worse.
  

• When your body is attacked by bacteria or viruses, the temperature of your body may get hotter. You have a fever.
  

  Fevers are one of the ways your body fights infections. For example, higher temperatures help to kill some bacteria. When you have a fever, your body hides some of the food that bacteria need to survive. Your immune system also makes more of the cells needed to attack the invaders.
  

  So making a fever is one of the ways your immune system helps you to get well. Fevers aren’t dangerous unless they get too high.
  

  Aspirin and aspirin-like medicines are often used to lower fevers. But if you’re under nineteen years old, you should never take aspirin or aspirin-like medicines to lower a fever unless a doctor tells you to. Aspirin-like medicines could cause you to develop Reye’s syndrome, a problem worse than a fever or a cold.
  

• Our immune system can turn against our own cells and attack them. When this happens, we actually become allergic to ourselves. Such attacks by our immune system can lead to diseases like asthma and intestinal problems.
  

  Most people think that parasites, such as hookworms, are disgusting and unhealthy. However, scientists have discovered that people who have hookworms aren’t attacked by their own immune systems. These parasites make stuff that controls the immune system and keeps it from attacking.
  

  For some serious diseases, doctors are actually giving people parasites to eat!
  

• When you get a cold or the flu, it takes a while for your immune system to make the special army needed to defeat the “bad guys.” That’s why it takes about ten days for you to get better. However, once your immune-system army has met and defeated the bad guys, it will be instantly ready to wipe them out if the two forces meet again—before you get sick.
  

  That’s how vaccines (vack-SEENZ) work. For example, a shot of flu vaccine prepares your body to recognize and destroy the enemy as soon as they meet. And you don’t get sick!
  

• It’s easy to think of bones as solid and rocky and not really alive. But bones are changing all the time.
  

  If bones didn’t change, you couldn’t grow taller and bigger. And your bones couldn’t heal if they broke. As you get older, the shape of your face will change as the bones in your skull change.
  

  Bones change because they’re made up of two kinds of cells that have opposite jobs. Osteoclasts [AHS-tee-uh-klasts] are constantly breaking down old bone. Osteoblasts [AHS-tee-uh-blasts] are always busy making new bone, mainly from the calcium in your milk and other food.
  

Would you like to find out more about the weird and wonderful stuff that goes on in your body? Here are some books for you:

• Body Warriors: The Immune System
  by Lisa Trumbauer (Chicago: Heinemann-Raintree, 2007). When bad stuff attacks, your body goes into amazing action. See what happens!
  

• The Magic School Bus Inside Ralphie: A Book About Germs
  by Joanna Cole (New York: Scholastic, 1995). It gets pretty crazy inside Ralphie when germs invade.
  

• Uncover the Human Body
  by Luann Colombo (San Diego: Silver Dolphin Press, 2003). Want to see what you look like on the
  inside?
  You’ll
  have fun putting yourself together—and taking yourself apart.
  

• The Brain: Our Nervous System
  by Seymour Simon (New York: Collins, 2006). Learn all about your squishy brain. And with all the great pictures, you’ll feel like you’re crawling into it!
  

Turn the page
for a sneak peek at
Andrew, Judy, and Thudd’s
next exciting adventure—
ANDREW LOST
IN THE DESERT

Available January 2008

Excerpt copyright © 2008 by J. C. Greenburg.
Published by Random House Children’s Books, a division of
Random House, Inc., New York.

“Erf!” said ant-sized Andrew Dubble. He was inside an empty bottle cap, bouncing into his cousin Judy.

Their uncle Al had glued the bottle cap to the dashboard of his jeep. It made a safe perch for Andrew and Judy to see the Australian desert as Uncle Al drove through it.

“Get off of me, Bug-Brain,” said Judy, shoving Andrew away. “It’s
soooo
hot in here!”

“It’s a rough trip through the desert, guys,” said Uncle Al. “The air conditioner isn’t working, so you’d better settle in for a long, hot, bumpy ride.”

meep …
“Desert air hot, hot, hot!” came a squeaky voice from Andrew’s shirt pocket. “Desert sand even hotter. Can fry egg on desert sand.”

It was Andrew’s little silver robot friend, Thudd. Uncle Al had invented him.

The afternoon sun burned through the windshield. The yellow sand stretched on forever. Here and there, patches of tall, prickly grass looked like resting herds of spiny porcupines. Now and then, a scraggly tree poked up like a skeleton.

“The desert is like an empty planet,” said Andrew.

Uncle Al shook his head. “It looks that way now,” he said. “But lots of strange creatures are sleeping or hiding underground during the hottest hours. They’ll come out to hunt when the sun goes down.”

Oinga! Oinga! Oinga!
came a sound from the front of the jeep. The jeep was slowing down.

Plunk … plunk … erk …

The jeep rolled to a stop. A ribbon of steam curled out from under the hood.

Uncle Al shook his head. “I’ll find out what’s wrong,” he said. “And while I’m doing that, I want you guys to stay put. The desert is a dangerous place. Some of the most dangerous animals in the world live here. And not all of them sleep during the day.”

“Okey-dokey, Unkie!” squeaked Thudd.

Uncle Al got out of the jeep and opened the hood. A cloud of steam puffed out.

“We’ve got a leak,” yelled Uncle Al from the front of the car. “I need to check underneath the jeep. This may take a while.”

The heat was making Andrew sleepy. He rested his head against the edge of the bottle cap.

Out of the corner of his eye, Andrew caught a glimpse of something moving. He turned to see a dark cloud whirling near the ground. It was spinning like a top and whipping up the sand. It was heading straight toward the jeep!