The Digestive System

1. The Digestive System Mr. Fox’s 7th Grade Science Class

3. Functions • Digestive System serves 3 main functions: • It breaks down food into molecules that can be used. • It allows those molecules into the blood to be carried to all parts of the body • Solid wastes are eliminated from the body.

4. The Gestions • Ingestion – getting food into the digestive system. • Digestion – breaking down the food. • Egestion – removal of solid wastes.

5. Types of Digestion • Mechanical digestion - food particles are broken down into smaller pieces. i.e. chewing your food. • Chemical digestions – chemicals produced by the body chemically alter the food and break it down into molecule later to be absorbed by the blood.

6. The Sugar/Enzyme Puzzle • Sugars have a specific enzyme to break them down. They fit together like a lock and key. • The suffix –ose means sugar • The Suffix –ase means enzyme

7. Glucose - Glucase Sucrose – Sucrase Lactose – Lactase

8. Parts of the Digestive System • Mouth and salivary glands – start the process of mechanical and chemical digestion, saliva starts the chemical digestion process.

9. Epiglottis – a flap of tissue that covers your trachea (wind pipe) when you swallow. • The idea of “wrong pipe” is caused when this doesn’t work right • Esophagus – muscular tube that connects your throat to your stomach, produces mucus to help food move along. Involuntary muscles move food down by peristalsis.

10. Stomach – J shaped organ where most mechanical digestion occurs. • Muscles churn the food, like a washing machine to break it into smaller pieces • Contains a strong acid ( hydrochloric acid ) to kill bacteria • allows an enzyme called pepsin to break down proteins

12. Small intestines – over 15 feet of digestive tubing!!! • Most chemical digestion takes place here • Absorption of food into the blood • Enzymes from the liver, pancreas and the small intestine continue to break down food. • Villi cover the inside of the intestines to absorb the nutrients.

14. Liver – the liver produces bile • Bile – a material that breaks fats into smaller pieces • Stored in the gall bladder until needed.

15. Pancreas – produces enzymes to help break down fats, starches and proteins. • Large Intestine – removes water from the waste and stores waste until it is eliminated