1. Human Body Systems Lesson 2 Terms and Definitions

2. Major Organs of the Digestive System 1.Mouth 2.Esophagus 3.Stomach 4.Small intestine 5.Large intestine 6.Rectum 7.Anus http://www.pediatricfeeding.org/images/gi_anatomy/A_digestive_system.png

3. Accessory Organs of the Digestive System 1.Tongue 2.Teeth 3.Salivary glands 4.Liver 5.Gallbladder 6.Pancreas Accessory Organs are important for mechanical and chemical digestion produce or store enzymes

4. What is the purpose of Digestion?

5. Digestion Purpose – break foods down into a form that can be absorbed into the bloodstream and transported to the cells of the body. Digestion is NOT a single activity BUT a series of processes. (Mechanical and Chemical)

6. Mechanical Digestion Mechanical Digestion – The physical breaking down, tearing, and mashing of food from large to small pieces. Example: Teeth tearing, tongue mashing, churning of food by muscles that line the digestive tract.

7. Chemical Digestion Chemical Digestion – Breakdown of the chemical bonds in nutrients so that they can be absorbed into the bloodstream. Example: Enzymes breaking down carbohydrates, fats, and proteins.

8. Fun Facts… Digestive Tract – Single convoluted tube 8-10 meters long

9. Muscle Activity in the digestive tract Peristalsis –wave like motions, caused by the muscles in the digestive tract, that move food slowly through the digestive tract. Crazy! – Peristalsis contractions are so strong that food would continue to move through your digestive system if you stood on your head! http://z.about.com/d/gymnastics/1/0/B/4/-/-/Step7.jpg

10. Muscle Activity in the digestive tract Sphincters – rings of thickened muscle that control the passage of food from one organ to another –Keeps food moving in the same direction (Down! Not back up!) Example – lips and anus, but also between organs.

11. Mucus Mucus – slippery secretion that coats the inner walls of the digestive tract and helps facilitate the movement of food. Also coats the lining of the stomach and small intestine to prevent acidic gastric juices from eating away at the stomach lining. http://www.thethinkingblue.com/pics/Stomachabc.jpg

12. Small Intestine… Small Intestine (SI) –Where most nutrient absorption occurs in duodenum (first 25 cm of SI) –Entire SI – 6-8 meters long http://cache3.asset-cache.net/xc/85824240.jpg?v=1&c=IWSAsset&k=2&d=C82013BE001AABCB31C0B7E4AA7CE1E8

13. Large Intestine Food – all that’s left is waste or Feces! What is a FART?

14. A fart is… Flatus – intestinal gases produced bacteria feeding on undigested wastes.

15. Digestive Timeline! 6 seconds 2 hrs 4 ½ hours 4-12 hours

16. 18 hours 12-24 hours