(SNC2D, SBI3U)
Wendy Chui
July 22nd , 2010
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!
It takes food from 12 hours – 2 days
to go through our body.
Section of Digestive
Tract
Time
Mouth
7 sec.
Esophagus
3 sec.
Stomach
10 min.
Small Intestine
7 hrs
Large Intestine
17 hrs
Outline of Presentation
1.
2.
3.
4.
5.
6.
7.
8.
Background information
Curriculum expectations
Student Misconceptions and Solutions
Placement of concept within unit
Lesson Sequence
Applications
Assessment and Evaluation
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.
SNC2D
SBI3U
• B3.5- Explain the interaction of different
systems within an organism and why such
interactions are necessary for the
organism’s survival
• E3.2- Explain the anatomy of the digestive
system and the importance of digestion in
providing nutrients needed for energy and
growth (ex. mechanical and chemical
processes, essential nutrients)
• E3.4- Describe some disorders related to the
respiratory, digestive, and circulatory systems
Expectations in Grade 10 and 11
• B3.4- Explain the primary functions of a
variety of systems in animals
Student Misconceptions
Misconceptions
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.
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
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)
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=Z7xKYNz9
AS0)
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=Z7xKYNz9
AS0
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
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
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)
4. Esophagus vs. Trachea
Solution:
• Pig dissection: anatomical differences
– Esophagus: white muscular tube beneath trachea
– Trachea: has cartilaginous rings that provide
strength and structure
Placement of Digestion in SBI3U
Genetics
Diversity of
Life
Evolution
Respiratory
System
Animal
Structure
and Function
Circulatory
System
Plants
Digestive
System
Lesson Sequence
Types of Feeding
Human digestion
Methods of Digestion
Health and Nutrition
Lesson Plan- Day 1
Topic.
Types of
Feeding
• Feeding
devices
• Evolution of
the digestive
tract
Expectations
E3.2
Teaching Strategies
• 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
Learning
styles
Visual
Verbal
Auditory
Assessment
Diagnostic:
What do
students already
know about
digestion?
Formative:
Ability to apply
concept to new
organisms
Day 2
Topic.
Human
Digestion
Expectations
E3.2
Teaching Strategies
• Video clip: Digestion intro
(Bill Nye)
• Direct instruction of
structures using PPT and
handouts
• Demo: Peristalsis
(pantyhose/sock and ball)
• Label diagrams
Learning
styles
Visual
Auditory
Assessment
Formative:
Homework
questions,
labeling
diagrams
Day 3
Topic.
Methods of
Digestion
• chemical and
mechanical
digestion
Expectations
E3.2
Teaching Strategies
• 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
Learning
styles
Visual
Auditory
Kinesthetic
Assessment
Formative:
Class discussion,
Ability to
connect activity
with function of
structures
Exit pass: What
is an example of
chemical and
mechanical
digestion?
Day 4
Topic.
Health and
Nutrition
Expectations
E1.2
E3.2
Teaching Strategies
• Introductory Question:
Which essential nutrients
do we need to obtain from
our food?
Learning
styles
Verbal
Visual
Auditory
Assessment
Formative:
What do
students already
know about
nutrition?
• Articles on healthy eating
• Direct Instruction on
essential nutrients, diets,
drugs and toxins, fitness
Class discussion,
Homework
questions
Day 5
Topic.
Pig Dissection
(at the end of
this Unit)
Expectations
E2.2
Teaching Strategies
• In pairs, students follow
dissection guide and
identify anatomical
structures
• students analyze the
relationship between the
respiratory, circulatory and
digestive systems
Learning
styles
Kinesthetic
Visual
Assessment
Summative:
Bell ringer,
quality of
dissection,
ability to
identify
structures
Addressing Different Learning Needs
Learning Needs
Teaching Strategies
Visual learners
• Label diagrams, graphic organizers, word webs,
animations,
• Virtual body
(http://www.medtropolis.com/VBody.asp)
Logicalmathematical
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 Evaluation
Possible 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/07Ja
n6ERwebquest.pdf
• Thyna’s PPT Presentation
Digestive Amusement Park
• A Day at Destination Digestion (STAO)
http://virtuallibrary.stao.ca/cruciblearticles/08Ja
n6cdigestionpark.pdf
Activity:
Create an amusement park ride for
one of the following structures:
1.
2.
3.
4.
5.
6.
Mouth
Esophagus
Stomach
Small intestines
Large intestines
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.
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:
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 activities
http://www.docstoc.com/docs/34097157/TheDigestive-System
• Activities:
http://mypages.iit.edu/~smile/bi9706.html