How Your Body Uses Food

1. How Your Body Uses Food Digestion

2. Digestion • The process of breaking down food into usable nutrients

3. The Mouth • Digestive process begins even before you eat • Just smelling and seeing can start saliva flowing • Saliva is the first of many digestive juices that act on food to break it down

4. The Mouth • Food is broken down physically by teeth • Food mixes with saliva and makes it easier to swallow and digest

5. The Esophagus • A long tube connecting the mouth to the stomach • Muscles contract and relax forcing food into the stomach

6. The Stomach

7. The Stomach • Widest part of the digestive system • Muscular pouch located on the left side of your body inside the rib cage • On average your stomach can hold about 4 cups of food

8. The Stomach • Walls manufacture gastric juices • A combination of acid and enzymes that helps in the chemical breakdown of the food • Food is churned until it turns into a thick liquid called chyme (KIME) • Chyme is released into the small intestine a little at a time

9. The Stomach • Different foods take different amounts of time to break down and leave the stomach • Carbohydrates take the shortest amount of time • Usually 1-2 hours • Proteins take longer • 3-5 hours • Fats take the longest • Up to 7 hours

10. The Small Intestine • Small winding tube between the stomach and the large intestine • Chyme is acted by three types of digestive juices • Bile • Pancreatic Juice • Intestinal Juice

11. Bile • Substance that helps your body digest and absorb fats • Produced in the liver • Stored in the Gall Bladder until needed

12. Pancreatic Juice • Contains enzymes that help break down carbohydrates, proteins, and fats • Produced by the Pancreas • A gland connected to the small intestine

13. Intestinal Juice • Produced in the small intestine • Works with other fluids to break down food

14. The Small Intestine • When broken down, carbohydrates are turned into a simple sugar called glucose • Body’s basic fuel supply • Fats are changed into fatty acids • Proteins are broken down into amino acids • Vitamins, minerals, and water do not need to be broken down • They are ready for action just as they are

15. Digestion Video • The Stages of Digestion • http://www.youtube.com/watch?v=A7jKCfx-0Mo&eurl=http%3A%2F%2Fvideo.google.com%2Fvideosearch%3Fhl%3Den%26source%3Dhp%26q%3DThe%2520stages%2520of%2520digestion%2520%26um%3D1%26ie%3DUTF-8%26sa%3DN%26tab%3Dwv&feature=player_embedded

16. Using Nutrients • Once food has been broken down into nutrients, digestion is complete • You body still has work to do though • It must absorb the nutrients and take them to where they can be used or stored

17. Absorption • Nutrients are absorbed into the bloodstream • Most absorption takes place in your small intestine

18. Processing and Storing Nutrients • After absorption, nutrients are carried through a blood vessel called the portal vein to the liver • One of the livers jobs is to turn nutrients into forms the body can use • Example: • Converts amino acids into different kinds of proteins • The proteins are then carried by the blood to where they are needed

19. Processing and Storing Nutrients • If not needed immediately nutrients are stored • Example: • Extra glucose is converted by the liver into glycogen • Stored in the liver and in muscles • If there is more than can be stored it is converted to body fat • Fats are then deposited throughout the body as and energy reserve

20. Processing and Storing Nutrients • Minerals are stored in various ways • Some examples: • Iron is stored in the liver and bone marrow • Fat-soluble vitamins are stored mainly in the liver and body fat

21. Quiz • How do nutrients get from the digestive system to the bloodstream? • Name two ways in which excess glucose can be stored. • Sketch a design for a poster or bulletin board showing how food is broken down into nutrients and how nutrients travel through the body.