The Mouth, Pharynx and Esophagus.
The mouth (oral cavity) is where digestion begins. In the mouth are the teeth, tongue and the salivary glands. The teeth chew the food. This is the beginning of mechanical digestion. The tongue moves the food around to help break it down and mix it with saliva. Saliva is sent out by the salivary glands and begins the chemical break down of starchy foods (like bread). Food is chewed and rolled into a bolus (lump) to be swallowed. When you swallow food, it passes through the pharynx (back of the throat) down into the esophagus. The esophagus is a long, muscular tube about 10 inches long (25 cm). Food passes down it to reach the stomach. The muscles of the esophagus contract to squeeze the food downward. This is called peristalsis.
Everything Kids HUMAN BODY BOOK
Learn about the body's systems: digestive, circulatory, respiratory, skeletal, muscular, nervous, endocrine, reproductive and your protective integument (your skin!) This book breaks down the human body and explains its parts and how it works in language a middle school student can understand -- or anyone who is interested in how our amazing bodies work. Also learn fun facts about the body, important vocabulary, interesting exercises and health tips and even do more than 30 body puzzles. Have fun on this 160-page anatomy adventure!
