(SNC2D, SBI3U)

1. Digestion (SNC2D, SBI3U) Wendy Chui July 22nd , 2010

2. Some Food for Thought… • What are the key structures and processes that aid in the digestion of the food that you just ingested? • How long do you think it will take for the food to travel through your body and be digested?

3. How long does it take to digest a donut? • It takes 72 hours for a donut to digest completely in your body! • You usually will pass it within 24 hours but it is the sugar that lingers around… • …so before you eat a sugary donut again, just think how long it’s going to stay within you!

4. It takes food from 12 hours – 2 days to go through our body.

5. Outline of Presentation • Background information • Curriculum expectations • Student Misconceptions and Solutions • Placement of concept within unit • Lesson Sequence • Applications • Assessment and Evaluation • References

6. Background Information • Digestion is briefly introduced in Grade 10 and studied in more detailed in Grade 11 Biology • The Grade 10 Biology unit includes topics such as cell division, cell specialization, organs and systems in animals and plants. • The Grade 11 Animals Functions and Structures unit provides more focus on three organ systems: Respiratory, Circulatory and Digestive.

7. Expectations • In both SNC2D and SBI3U: • Dissections are used to compare the relationships between the organ systems. • The use of technology in medical treatments is discussed.

8. Expectations in Grade 10 and 11

9. Student Misconceptions

10. 1. Gravity causes food to move through our digestive tract. • Many students believe that gravity is primarily responsible for moving food to the stomach. • Although gravity helps, peristaltic motions of the esophageal muscles ensure that food reaches the stomach. • That is why even astronauts are able to swallow and digest food.

11. 1. Gravity causes food to move through our digestive tract. Solutions: • Peristalsis demonstration (sock/pantyhose and tennis ball) • Video on astronauts living in space (Bill Nye on Digestion) • Video on food movement through digestive system

12. Peristalsis Demo Materials: • Long sock or pantyhose • Small ball Squeeze the ball along the length of the sock to simulate peristaltic motion (contraction of circular and longitudinal muscles)

13. Video on astronauts living in space (Bill Nye pt.2, 3:26-4:15)

14. 2. We can extract nutrients from our food because it is broken down mechanically by the mouth. • There are two types of digestion: mechanical and chemical • Mechanical digestion: mouth (teeth and tongue), peristalsis, stomach muscles • Chemical digestion: acids and enzymes in saliva, stomach, intestine, accessory organs (gall bladder, pancreas)

15. 2. We can extract nutrients from our food because it is broken down mechanically by the mouth. Solutions: • Graphic organizer that illustrates the different types of digestion • Breakdown of Carbohydrates Mini-Lab • Digestive System video (http://www.youtube.com/watch?v=Z7xKYNz9AS0)

16. Mini-Lab: Breakdown of Carbohydrates • Place a piece of cracker or bread in your mouth and note the original taste. Chew the cracker several times and allow it to dissolve in your mouth for 3-5 minutes. Discussion: • What did you notice about the taste of the cracker over time? • How can you explain these results, based on what you know about enzymes in the saliva?

17. Explanation: • Starches (a type of carbohydrate) are made up of smaller sugar molecules. • An enzyme found in the saliva, amylase, breaks down starch into simple sugars so that the it can be used as energy for the body. • Q: How could you extend the activity?

18. Saltine Cracker Challenge • How many soda crackers can you eat in 60 seconds?

19. Digestive System Animation • http://www.youtube.com/watch?v=Z7xKYNz9AS0

20. 3. The small intestine is shorter than the large intestine. • A human’s small intestine is 7 metres long, whereas the large intestine is 2 metres long • The large intestine has a bigger diameter

21. 3. The small intestine is shorter than the large intestine. Solutions: • Provide a physical model of the length of the small intestines vs. large intestines (ex. measuring string) • Pig Dissection: unravel the large and small intestines and measure or compare

22. 4. Esophagus vs. Trachea • Students often confuse the esophagus (part of digestive system) with the trachea (part of respiratory system) • Anatomically, they are very close to each other and often linked (ex. choking)

23. 4. Esophagus vs. Trachea Solution: • Pig dissection: anatomical differences • Esophagus: white muscular tube beneath trachea • Trachea: has cartilaginous rings that provide strength and structure

24. Placement of Digestion in SBI3U

25. Lesson Sequence

26. Lesson Plan- Day 1

27. Day 2

28. Day 3

29. Day 4

30. Day 5

31. Addressing Different Learning Needs

32. Applications • Development of dietary products and fitness equipment (E1.2) • Investigate disorders related to digestive system (E3.4) • Medical Detectives assignment • Student sample

33. Assessment and EvaluationPossible ideas for activities and projects in Animal Structures and Functions Unit • Medical Detectives • You are a doctor! Diagnose this patient. • Digestive Amusement Park • How does our digestive system relate to Wonderland?

34. Medical Detectives • ER: A Webquest (from STAO) http://virtuallibrary.stao.ca/cruciblearticles/07Jan6ERwebquest.pdf • Thyna’s PPT Presentation

35. Digestive Amusement Park • A Day at Destination Digestion (STAO) http://virtuallibrary.stao.ca/cruciblearticles/08Jan6cdigestionpark.pdf

36. Activity: Create an amusement park ride for one of the following structures: • Mouth • Esophagus • Stomach • Small intestines • Large intestines • Anus

37. Annotated References Digestive System Animation. Retrieved July 20th, 2010, from <http://www.youtube.com/watch?v=Z7xKYNz9AS0> • This video is great for reinforcing the concepts taught in digestion. Students can visually see the movement of food through the body. Discovery Kids: Yucky Gross and Cool Body. Retrieved July 20th, 2010, from <http://yucky.discovery.com/flash/body/> • This site provides answers to fascinating questions that your students might ask about the human body. Medtropolis: The Virtual Body. Retrieved July 20th, 2010, from <http://www.medtropolis.com/VBody.asp> • This website allows students to highlight certain structures and learn about them in detail. STAO Virtual Library. Retrieved July 20th, 2010, from <http://www.stao.org/VL2/VL2.php> • This site has great resources for different grades and levels. It’s free to access and has many creative ideas for projects and assignments.

38. Thanks for being a great audience! …and special thanks to my mentor, Iris!

40. Activity: • For a College-level Biology class (SBI3C), what would you include and omit from the following handout? Why? • Expectations from this Unit: • E3.3- Describe the anatomy and physiology of the digestive system, the mechanisms of peristalsis, absorption, and mechanical and chemical digestion, and the function of the kidneys

41. 5. Food travels quickly through our digestive system. Q: How long does it take for food to travel through our digestive tract? • It takes food from 12 hours – 2 days to go through our body.

42. 5. Food travels quickly through our digestive system. Solution: Table displaying the time it takes for food to pass through each section of the digestive tract in an average adult human:

43. Other Activities • Labs: Investigating the presence of nutrients in various food items (McGH- BLM 10-7)

44. Stomach Simulation • Place crackers inside a zip loc bag • The bag simulates the stomach, which is a muscle that squeezes food • Pour a little orange juice or coke • Squeeze the contents in the bag for 2 minutes • Observe what happens to the bread

45. Materials Needed • Socks • Ball • Crackers

46. Lab activities http://www.docstoc.com/docs/34097157/The-Digestive-System • Activities: http://mypages.iit.edu/~smile/bi9706.html