The stomach is a storage tank for digesting food. Its walls have a lot of muscle in them so it can stretch if you eat a lot of food. It can hold up to a gallon of food. When it is empty, it shrinks back down and its walls fold up into wrinkles called rugae. The lining of the stomach has lots of goblet cells that make a slimy mucous that protects the stomach from the powerful acids it uses to digest food. There are also gastric pits that make the gastric juice. Gastric juice is a mixture of chemicals that digest food. It includes; hydrochloric acid (HCL) that kills bacteria on the foods you eat and helps the other chemicals work. Another chemical in gastric juice is pepsin, the chemical that digests proteins. The stomach is where protein digestion begins. The stomach does both mechanical and chemical digestion. It churns the food and mixes it with the gastric juices. By the time it leaves the stomach, the food is broken down into a creamy paste called chyme. Now it is ready to move on to the small intestine.
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!