DRAFT

How Many Burritos Does a Stomach Hold?

Anatomy and Physiology

Grade Level
Standards	Inquiry Skills
		Students will design and conduct scientific investigations
		Students will communicate scientific procedures and explanations
	Human Anatomy and Physiology Content
		Students will understand how the digestive system receives, modifies, and absorbs food, and eliminates solid wastes

Objectives	To explain and perform an inquiry experiment based on the stomach and how gastric juices digest the major nutrients.
Materials and Activities
Engage	Pose the following questions and brainstorm to test for prior knowledge: How much food can the stomach hold? How many burritos will it take to fill your stomach? Show me where your stomach is located. What does the burrito look like in the stomach?
Explore	Perform a quick lab as directed below: Divide students into groups of four. Lab groups should predict how the proteins and fats are broken down in the stomach. Take a small section of a burrito and place it in a test tube and mix with amylase to simulate the breakdown of starches in the oral canal. Add the simulated gastric juice with 0.5% HCl, pepsin, rennin, lipase, or Adolph's meat tenderizer to the burrito. Record observations
Explain	Answer questions from engage. Explain the basic anatomy of the stomach to include the cardiac sphincter, rugae, surface area, mucosa, submucosa, and gastric juices. Include the point that the average human stomach can hold about a gallon of food and that 2-3 liters of gastric juices are produced daily.
Explore	Question-Why doesn't the stomach digest itself and why does acid normally remain in the stomach? Demonstration- Prepare two petri dishes with a small portion of a burrito. Cover one of the petri dishes with a plastic bag and then drop 0.5% HCl on each. Have students make a prediction prior to the actual demo. Provide a brief explanation of mucus protection.
Evaluation	For homework, students should create a concept map with the major points of the last four lessons.

Teacher notes/reminders: This is the fourth lesson in a series of 6 utilizing an inquiry-based model. The lessons are:

1. The Digestive travels of a Burrito
2. Where Does a Burrito Go First?
3. How does Swallowing Effect the Burrito?
4. How Many Burritos Does a Stomach Hold?
5. What If That Burrito Was Bad?
6. Do Cows Eat Burritos?

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Updated 09/01
Last Reviewed 10/2001

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