Afterword

Thank you for traveling all the way through this book. Together, we followed one breath from the tip of the nose to the deepest corners of the lungs and back out again. On the way, we met hairs and mucus, sneezes and coughs, tonsils and a little door called the epiglottis, a moving carpet of tiny hairs, branching tubes, hundreds of millions of tiny air sacs, cleaner cells, red blood cells and the strong muscle that pulls air in.

The most surprising thing about these guards is how quietly they work. You do not have to tell your nose to warm the air or tell your cleaner cells to eat a germ. They simply do it, every minute of every day, even while you sleep. Most of the time, you never notice them at all.

Now that you know they are there, you can help them. Washing your hands, sleeping well, playing outside, drinking water, covering your coughs and sneezes, and staying away from smoke are small things, but they make the guards' work easier. When you feel a little sick, remember that many of those feelings are signs of your guards hard at work.

The next time you take a deep breath, perhaps you will think of the long journey that air is about to take. And perhaps you will feel a small thank-you for the guards inside every breath.

For Grown-Ups: Reading and Talking Together

Children understand and remember more when they can talk about what they have read. You do not need to be an expert to have a good conversation. Simple questions, a little curiosity and the key words at the end of each chapter are enough. Here are a few ideas.

Read in short sessions. One chapter, or even half a chapter, at a time is plenty. Stopping while your child is still curious makes the next reading something to look forward to.

Use the body. Many chapters invite children to feel their own breathing, put a hand on the chest or notice a sneeze. Gentle moments like these make the ideas real. Never try anything that is uncomfortable or unsafe.

Ask open questions. Questions that begin with "why", "how" or "what do you think" lead to better conversations than questions with a yes or no answer. It is fine to answer "I do not know, let us look it up together."

Keep health talk calm. If your child asks about an illness, it can help to explain what the body is doing to protect itself, as this book does. If your child, or anyone in your family, has symptoms that worry you, please talk to a doctor or another health professional.

Questions to Talk About, Chapter by Chapter

Chapter 1: What do you think would happen if air had no dust or germs at all? Why does the body still need guards?

Chapter 2: Why is it better to breathe in through your nose than through your mouth when you can?

Chapter 3: When was the last time you sneezed? What do you think your body was trying to push out?

Chapter 4: Why do you think the tonsils sit right where food and air both pass?

Chapter 5: Why is it a good idea to sit down and chew slowly while you eat?

Chapter 6: How is the windpipe like an escalator? Where does the mucus go in the end?

Chapter 7: Can you draw the breathing tree? How many times do its branches split?

Chapter 8: Why do you think the lungs need so many tiny air sacs instead of one big balloon?

Chapter 9: If you were a cleaner cell, what would you do when you found a germ?

Chapter 10: Where does the oxygen go after it leaves the lungs?

Chapter 11: Put a hand on your belly and breathe slowly. What do you feel moving?

Chapter 12: Why might a fever be a sign that the body is fighting back?

Chapter 13: When are the most important times to wash your hands?

Chapter 14: What are some ways we can keep the air clean at home?

Chapter 15: Which guard surprised you the most, and why?

Quiz: How Much Do You Remember?

Try these questions on your own or with your family. The answers are below. Do not worry if you need to look back at a chapter. Looking back is a great way to learn.

Question 1: Which gas from the air does your body need to use the energy in food?

Question 2: What two things inside your nose catch dust and germs before they go deeper?

Question 3: What is the name of the little door that closes over the windpipe when you swallow?

Question 4: What do the tiny hairs in the windpipe do with mucus?

Question 5: What are the tiny air sacs at the ends of the smallest breathing tubes called?

Question 6: What is the name of the cleaner cells that eat germs and dust in the lungs?

Question 7: Which part of the blood carries oxygen around the body?

Question 8: Which large muscle under the lungs moves down when you breathe in?

Question 9: What does the body make that remembers a germ so that it can fight it faster next time?

Question 10: Name three everyday things you can do to help your breathing guards.

Answers

1: Oxygen. 2: Nose hairs and sticky mucus. 3: The epiglottis. 4: They sweep it up and out of the lungs, toward the throat. 5: Alveoli. 6: Macrophages. 7: The red blood cells. 8: The diaphragm. 9: Memory cells and antibodies. 10: For example, washing your hands, sleeping well, covering coughs and sneezes, playing outside and staying away from smoke.

About the Information in This Book

This book was written from well-established knowledge of human biology and medicine, as explained in school science, standard reference works and the public health information of official health organizations. Numbers such as the count of air sacs or breaths per minute vary from person to person, so they are given as approximate ranges.

If you are worried about any symptom, please talk to a doctor.