9781422280355

Chapter One

What Is the Digestive System?

I f you or someone you love has a digestive disease or disorder, such as Crohn’s disease, ulcerative colitis, celiac disease, or irritable bowel syndrome (IBS), you probably have a lot of questions about what is happening to your or that person’s body. Before you can understand how disease affects you, it helps to understand how your body works. In this chapter, you’ll learn about how the digestive system functions. Your Body Needs Energy Energy. Your body needs it for everything you do: running, talking, even turning the pages of this book. You also need energy to take care of automatic bodily processes. These are necessary activities your body conducts unconsciously—that is, without thinking about it. Energy is the foundation of all basic life processes. Your cells need energy just to survive. During

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