(SNC2D, SBI3U)

Wendy ChuiJuly 22nd , 2010

Some Food for Thought…Some Food for Thought…

1. What are the key structures and processes that aid in the digestion of the food that you just ingested?

2. How long do you think it will take for the food to travel through your body and be digested?

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!

Section of Digestive Tract

Time

Mouth 7 sec.

Esophagus 3 sec.

Stomach 10 min.

Small Intestine 7 hrs

Large Intestine 17 hrs

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

Outline of Presentation

1. Background information2. Curriculum expectations3. Student Misconceptions and Solutions4. Placement of concept within unit5. Lesson Sequence 6. Applications7. Assessment and Evaluation8. References

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.

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.

Expectations in Grade 10 and 11 Expectations in Grade 10 and 11

Student MisconceptionsStudent MisconceptionsMisconceptions

1. Gravity causes food to move through our digestive tract.

2. We can extract nutrients from our food because it is broken down mechanically by the mouth.

3. The small intestine is shorter than the large intestine.

4. Confusion between the esophagus and the trachea

5. Food travels quickly through our digestive system.

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.

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

1. Gravity causes food to move through our digestive tract.

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)

Video on astronauts living in space

(Bill Nye pt.2, 3:26-4:15)

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)

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)

2. We can extract nutrients from our food because it is broken down

mechanically by the mouth.

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?

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?

Saltine Cracker Challenge

• How many soda crackers can you eat in 60 seconds?

Digestive System Animation

• http://www.youtube.com/watch?v=Z7xKYNz9AS0

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

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

3. The small intestine is shorter than the large intestine.

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)

Solution:• Pig dissection: anatomical differences

– Esophagus: white muscular tube beneath trachea– Trachea: has cartilaginous rings that provide

strength and structure

4. Esophagus vs. Trachea

Placement of Digestion in SBI3U

Lesson Sequence

Lesson Plan- Day 1Lesson Plan- Day 1Topic. Expecta-

tions Teaching Strategies Learning

stylesAssessment

Types of Feeding • Feeding devices• Evolution of the digestive tract

E3.2 • Discussion: Do all organisms obtain food the same way?

• Individual work: Fill out chart on different feeding types using textbook

• Activity: Determine the feeding types of different organisms(independent and group inquiry)

• Direct instruction of concept via handout

VisualVerbalAuditory

Diagnostic: What do students already know about digestion?

Formative: Ability to apply concept to new organisms

Day 2Day 2Topic. Expecta-

tions Teaching Strategies Learning

stylesAssessment

Human Digestion

E3.2 • Video clip: Digestion intro (Bill Nye)

• Direct instruction of structures using PPT and handouts

• Demo: Peristalsis (pantyhose/sock and ball)

• Label diagrams

VisualAuditory

Formative:Homework questions, labeling diagrams

Day 3Day 3Topic. Expecta-

tions Teaching Strategies Learning

stylesAssessment

Methods of Digestion• chemical and mechanical digestion

E3.2 • Mini-Lab: Breakdown of Carbohydrates

• Direct instruction of types of digestion using PPT and handouts

• Class activity: Digestive System Simulation (Caitlin’s Best Practice)

• Graphic organizer: Chemical vs. Mechanical Digestion

Visual AuditoryKinesthetic

Formative:Class discussion, Ability to connect activity with function of structures

Exit pass: What is an example of chemical and mechanical digestion?

Day 4Day 4Topic. Expecta-

tions Teaching Strategies Learning

stylesAssessment

Health and Nutrition

E1.2E3.2

• Introductory Question: Which essential nutrients do we need to obtain from our food?

• Articles on healthy eating

• Direct Instruction on essential nutrients, diets, drugs and toxins, fitness

VerbalVisualAuditory

Formative: What do students already know about nutrition?

Class discussion, Homework questions

Day 5 Day 5 Topic. Expecta-

tions Teaching Strategies Learning

stylesAssessment

Pig Dissection(at the end of this Unit)

E2.2 • In pairs, students follow dissection guide and identify anatomical structures

• students analyze the relationship between the respiratory, circulatory and digestive systems

KinestheticVisual

Summative:Bell ringer, quality of dissection, ability to identify structures

Addressing Different Learning NeedsLearning Needs Teaching Strategies

Visual learners • Label diagrams, graphic organizers, word webs, animations, • Virtual body (http://www.medtropolis.com/VBody.asp)

Logical-mathematical learners

• Flowchart of a meal• Length of each section

ELL and Special Needs

• Preview vocabulary, label diagrams• More teacher guidance and scaffolding •Extra time

Applications

• Development of dietary products and fitness equipment (E1.2)

• Investigate disorders related to digestive system (E3.4)

– Medical Detectives assignment– Student sample

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?

Medical Detectives

• ER: A Webquest (from STAO)http://virtuallibrary.stao.ca/cruciblearticles/

07Jan6ERwebquest.pdf

• Thyna’s PPT Presentation

Digestive Amusement Park

• A Day at Destination Digestion (STAO)http://virtuallibrary.stao.ca/cruciblearticles/

08Jan6cdigestionpark.pdf

Activity: Create an amusement park ride for

one of the following structures:

1. Mouth2. Esophagus3. Stomach4. Small intestines5. Large intestines6. Anus

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.

Thanks for being a great audience!

…and special thanks to my mentor, Iris!

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

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.

Solution:Table displaying the time it takes for food to pass through each section of the digestive tract in an average adult human:

5. Food travels quickly through our digestive system.

Section of Digestive Tract

Time

Mouth 7 sec.

Esophagus 3 sec.

Stomach 10 min.

Small Intestine 7 hrs

Large Intestine 17 hrs

Other Activities

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

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

Materials Needed

• Socks• Ball• Crackers

• Lab activitieshttp://www.docstoc.com/docs/34097157/The-

Digestive-System

• Activities:http://mypages.iit.edu/~smile/bi9706.html