Student Exploration: Digestive System Vocabulary : absorption, amino acid, carbohydrate, chemical digestion, chyme, complex carbohydrate, digestion, digestive system, elimination, enzyme, fat, fatty acid, fiber, food calorie, mechanical digestion, monoglyceride, nutrient, peristalsis, protein, starch, sugar, villus
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Why do we need to eat food?
2. How do you think our bodies break food down into useful nutrients ? __
Gizmo Warm-up The digestive system is a group of organs that does three things: ● First, the digestive system breaks food down into useful nutrients, a process called digestion . ● Next, the nutrients move into the bloodstream, a process called absorption .
● Finally, the leftover waste is removed from the body, a process called elimination .
With the Digestive System Gizmo™, you can arrange the organs of the digestive system any way you like. To begin, look at the organs on the LARGE ORGANS tab. Place your cursor over each organ to learn more about it.
1. Which organs allow nutrients to be absorbed?
2. Which organ stores and compacts waste before it is eliminated?
3. Which two organs help to break food down mechanically
Goal: Design your own digestive system.
1. Explore : Read the descriptions of the large organs, as well as those of the small organs on the next tab. Fill in the names of the organs that serve the functions listed below:
This organ absorbs water and vitamin K from digested food.
This organ produces enzymes that break down nutrients.
These tiny blood vessels transport absorbed nutrients.
These cells produce hydrochloric acid (HCl).
These cells produce pepsin , which breaks down proteins
2. Build : Now it is time to design and build your own digestive system! Start with the LARGE ORGANS tab to build a basic system, starting with the Mouth/pharynx . Next, attach organs from the SMALL ORGANS tab to the large organs to complete your system. Draw a picture of your system below. (If you like, open the Tools menu and click Screen shot . Right-click the image, choose Copy Image , and paste the image into a blank document.)
3. Predict : How well do you think your system will digest food? Explain your reasoning.
Activity A (continued from previous page) 4. Prepare : Select the FOOD tab. The energy we get from food is measured in food calories (Calories). Each Calorie is equal to 4,184 joules of energy. Calories are found in the three main nutrients in food: carbohydrates ( sugars and starches ), proteins , and fats . Drag the Cheeseburger above the mouth in your digestive system. How many Calories in the cheeseburger come from carbohydrates, proteins, and fats? Carbohydrate Calories: Protein Calories: Fat Calories:
5. Run the Gizmo : Click Play ( ), and observe the food moving through the digestive system. The muscular contractions that push food through the system are called peristalsis . When food has finished passing through the system, you will see a message. A. What percentage of Calories were absorbed by your system?
B. What percentage of water was absorbed?
C. Based on these results, how well do you think this digestive system worked? Explain
6. Revise : Click Reset ( ). Rearrange the organs of your system to try to improve your results. Describe how you changed your system below
7. Test : Click Play . List the results below. Did the system improve
Percentage of Calories absorbed: Percentage of water absorbed:
8. Explain : If your system improved, why do you think this was so?