Human Digestion

1. Human Digestion Science 7 by: Mr. Rockensies Aim: How does the digestive system break down food into nutrients? Do Now: How many feet does your food travel through the digestive system? HW: Worksheet

2. The Stormy Sea

3. “Then, the valve to the stomach opens and pizza mush lands in your stomach!”

4. “The small intestine looks like a strange underwater world filled with things that resemble small finger-like cactuses.”

5. “A glorious, if slightly stinky, journey, don't you think?”

6. In-class Exercises Name the term used to describe the muscular contraction that pushes your food down the esophagus and into the stomach. peristalsis Describe the role that mucus plays in the stomach. Acts as a liner, protecting the stomach from acid burns Determine the 5 steps that food takes as it travels through the digestive system. • Eat the food • Food enters stomach and is further digested by acid • Nutrients are absorbed by the small intestine • Waste not absorbed has water taken out by large intestine • Waste is removed from the body

7. In-class Exercises What is digestion? The breakdown of food so that it can be absorbed EDDiE Di E Diffusion Eat/Ingest You chew food with your teeth, breaking it down into smaller pieces. Saliva breaks down starch molecules into simple sugars. After the stomach, the food enters the small intestine and is mixed with juices filled with enzymes that further break down food to be absorbed by villi D Digestion E Eliminate/ Egest The esophagus pushes the food down to the stomach using peristalsis. The stomach fills with acid and contracts to mix the food and acid. Food then travels to the colon, or large intestine, where it is dehydrated. The water is removed and the remaining waste is then pushed out of the body by the rectum through the anus

8. In-class Exercises How is food broken down? a) physical changes Food is broken down mechanically – chewing, mixing, grinding Ex: Teeth chewing, stomach churning b)chemical changes Food is mixed with acids and digestive juices containing enzymes to further break down food and release nutrients for absorption

9. In-class Exercises 1) E - eat/ingest Mouth, teeth, salivary glands, tongue, esophagus 2) D - digest Stomach, pancreas, liver, gall bladder, small intestine 3) Di - diffusion Small intestine (villi), large intestine 4) E - eliminate/egest Large intestine, rectum, anus Hypothesize what might happen if H2O was not removed during the final stages of digestion in the large intestine.