Transcript Digestive system

Digestive system
http://www.mennellmedia.co.uk/VideoProjects/ToiletTales/ToiletTales.html
H&W Outcome
H&W
Throughout this unit, the following
Health and Wellbeing learning outcome
will be covered in great detail:

I am developing my understanding of the
human body and can use this knowledge to
maintain and improve my wellbeing and
health.
HWB 3-15a / HWB 4-15a
Starter – Answer on
boards
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Why do we need food?
Lesson 4 – Learning
outcomes
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Know the main food groups and their
functions
Know how to carry out food tests for
starch, sugar and protein
Examine food labels to identify which
food groups are present in different
foods
Why do we have
to eat?
H&W
 We have to eat to stay alive. Everybody knows
that.
 Food is your body’s fuel. It supplies the energy to
keep your body working.
 But food has other important jobs to do. Can
you think of anything else that your
food is needed for? Think for 1 minute, discuss with a
partner for 1 minute, then share ideas with your
group.
 Copy the heading, and write a sentence to
describe three things that our food is used for.
Chemicals in food
H&W
Our food is a mixture of many different chemicals.
These food chemicals can be split into groups. The
three major groups are:
 Carbohydrates (starch and sugars) which are used
for energy.
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Fats which are also for energy.
Proteins which are used for growth and repair of cells
and tissues.
As well as these, our food also contains very small quantities
of vitamins and minerals for health, fibre to keep
food moving through the gut, and water for chemical reactions.
Food Groups
Food group
H&W
Use in the body
Carbohydrate
Fat
Growth and repair
For chemical reactions
Fibre
Vitamins and minerals
Food tests
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We can test food to find out what food
chemicals it contains.
Your teacher will demonstrate how to
do 3 different food tests.
You will then test some foods to see
what they contain.
Food tests
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TEST FOR GLUCOSE (SUGAR)
1. Add blue Benedict’s solution to the food in a test tube.
2. Heat in a beaker of boiling water for 5 minutes.
3. The solution turns to green or orange if glucose is present.
NEGATIVE RESULT(Blue)
POSITIVE RESULT(Orange)
TEST FOR STARCH
1.
2.
3.
Put a small amount of food in a dimple in a spotting tile.
Add iodine solution.
If the solution turns black, starch is present.
This is a negative
result for starch
This is a positive
result for starch
TEST FOR PROTEIN
1.
2.
3.
Mix the food with water in a test tube.
Add Biuret solution.
If the solution changes to purple, protein is present.
Negative result
for protein
Positive result
for protein
Food tests summary
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2.
3.
COPY
TEST FOR GLUCOSE (SUGAR)
1. Add blue Benedict’s solution to the food in a test
tube.
2. Heat in a beaker of boiling water for 5 minutes.
3. The solution turns from blue to green or orange
if glucose is present.
TEST FOR STARCH
Put a small amount of food in a dimple in a spotting
tile.
Add iodine solution.
If the solution turns from orange to black, starch is
present.
TEST FOR PROTEIN
Mix the food with water in a test tube.
Add Biuret solution.
If the solution changes from blue to purple, protein
is present.
What to do
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Collect a food sample from your
teacher.
Test the food for
- glucose by heating with Benedict’s
- starch by adding iodine in a spotting
tile
- protein by adding water then Biuret
Record your results in the table.
Collect another food and repeat.
COPY
Food tests results
Food
tested
Glucose
test
Starch test Protein
test
if present
x if absent
Food Testing
Food Type
Solution used
Protein
Sugar
(glucose)
Colour Change
Blue to Lilac
Benedict’s
Solution + heat
Iodine
Food tests - conclusion
Write one or two sentences to summarise
what you found out.
 Collect some food labels, and study the
‘Nutritional Information’. Look at the values
for ‘per 100g’.
 Make three lists as shown below and write
the names of foods in the correct list.
Foods high in Foods high in Foods high in
carbohydrates
fat
protein
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‘Food and drugs’ animation and quiz
Food detective game
Test your knowledge 4
1.
2.
3.
4.
5.
6.
7.
Name the food group that is needed for
growth and repair.
Name the two types of carbohydrates.
What are fats used for in the body?
What chemical is used to test for starch?
What colour does Biuret turn if protein is
present?
Name two foods high in protein.
Other than carbohydrate, protein and fat,
name two other components of a healthy
diet.
ANSWERS ON NEXT SLIDE
Answers
1.
2.
3.
4.
5.
6.
7.
Protein
Starch and sugar
Energy
Iodine
Blue to purple
Meat, fish, eggs, nuts, beans.
Vitamins, minerals, fibre, water.
Lesson 5 – Learning
outcomes
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H&W
Know that the energy value of
different foods varies
Carry out an experiment to compare
the energy value of different foods
Know the structure and function of the
digestive system
Energy in foods
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Know that the energy value of
different foods varies
H&W
COPY
Energy content of food
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H&W
It’s a fact! Some people really do need to
eat more food than others. (Why do you
think this is? Discuss with a partner.)
It depends on a number of factors like your
age, your size and how active you are.
Different foods give you different amounts
of energy. The energy value in food is
measured in kilojoules (kJ).
COPY AND COMPLETE
Energy content of food
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H&W
Study the ‘Nutritional information’ on 6 food labels,
and find the energy in ‘kJ per 100g’.
Copy and complete the table.
Name of food
Energy (kJ per 100g)
Typical information that you would see on a food label
H&W
You may see this label
Information is given on food labels to help promote a balanced diet
Comparing energy
content of foods
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You can estimate the energy content
of a food by burning it.
When it burns, the chemical energy in
the food is converted to heat and light
energy.
If we measure how much heat is given
off, we can compare different foods to
find out which has most energy.
Design the experiment
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With a partner, discuss how you could set up an
experiment to compare the energy in sugar, flour
and rice.
Please note - you cannot put a thermometer into a
flame!
Make brief notes of your ideas. Draw a diagram to
show how the apparatus will be set up.
Think about what will need to be kept the same
each time to make it a fair test.
List any safety precautions that will be needed.
Discuss your ideas with your teacher.
Do the experiment
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Here is one method to do this
experiment which you could use.
thermometer
boiling tube
with cold
water
Deflagrating spoon
Clamp stand
Burning food
Set fire to food in a
bunsen burner, then
quickly place spoon
under boiling tube
COPY AND COMPLETE
Results
FOOD
Starting
temperature
( °C)
Final
temperature
( °C)
Rise in
temperature
( °C)
COPY AND COMPLETE
Conclusion
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The food with the highest energy
content was ___________. I knew this
because it released the most
________ energy.
Digestive system
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Food has to get into the bloodstream to be
delivered to all cells of the body
First it has to be broken down or digested
so that the molecules are small enough to
be absorbed through the wall of the
intestine and transported in the blood.
The digestive system is a series of organs
which chemically break down the food into
small soluble molecules.
This chemical breakdown is carried out by
digestive juices released into the mouth,
stomach and small intestine.
Digestive system
mouth
Your teacher will
show you the
organs of the
digestive system on
a ‘Model Body’.
Use this diagram to
help you to label
the handout sheet
on the Human
Digestive System.
Then stick the
sheet into your
notebook.
salivary glands
gullet
liver
gall bladder
pancreas
small intestine
appendix
stomach
large intestine
rectum
anus
http://kidshealth.org/kid/htbw/digestive_system.html
This web site has a digestive diagram click on it .
You can move your cursor over the diagram and
an explanation appears
http://monarchcenters.wikispaces.com/Digestion+Overview
This is a animation of how different foods would be
digested.
Test your knowledge 5
1. Put these organs in the order that food
passes through them :
small intestine, gullet, mouth, large
intestine, anus, rectum, stomach
2. Name two factors which affects how
much energy you need in a day.
ANSWERS ON NEXT SLIDE
Answers
1.
2.
Mouth, gullet, stomach, small
intestine, large intestine, rectum,
anus.
Your age, body size, activity.
Lesson 6 – Learning
outcomes
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Know the role of enzymes in digestion
Carry out an experiment to
demonstrate the action of an enzyme
Digestion video clip
Digestive enzymes
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COPY
Digestive juices released into the
mouth, stomach and intestines contain
enzymes which chemically break down
the food.
There are many different enzymes
each of which breaks down a different
type of food.
One of these enzymes is amylase. It
breaks down starch, a large molecule,
into smaller sugar molecules.
Digestion experiment
COPY
Aim : to find out the effect of amylase on starch
Thermometer
Water at 37°C
10ml starch +
2ml distilled
water
10ml starch +
2ml amylase
Method
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7.
Prepare a beaker of water at 37°C using
kettle and tap water.
Add 10ml starch solution to two boiling
tubes.
Add 2 ml water to one and 2ml amylase to
the other.
Place both test tubes in the beaker of
water.
Immediately stir then remove a drop from
each test tube and put on separate dimples
on a spotting tile.
Add iodine to both samples.
After 10 minutes repeat steps 5 and 6.
Method : Now write a brief outline of the method you
used in your own words. Remember to mention all the
equipment you used and the volumes you measured.
Results
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Copy and complete the table.
Contents of tube
Starch + water
Starch + amylase
Result of
starch test at
start
Result of
starch test
after 10 mins
Conclusion
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COPY AND COMPLETE
amylase
The enzyme _________
breaks
starch into sugar.
down ______
Answers
Test your knowledge 6
Answer these questions in
sentences
1. Why was the test tube with starch and
water used?
2. Why were the test tubes placed in
water at 37°C?
3. Why must starch be broken down in
the digestive system?
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ANSWERS ARE ON THE NEXT SLIDE
Answers
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1. To compare to the experiment / to
prove that amylase is needed to break
down starch / as a control experiment
2. To create the same temperature
conditions found in the human body
3. To produce small molecules that
can be absorbed and transported in
the blood
Lesson 7 – Learning
outcomes
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Know what happens to digested food
and undigested food
Know what is meant by a balanced
diet
Study your own diet to assess whether
it is healthy
What happens to digested
food?
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COPY
After digestion, all the simple food chemicals
are absorbed through the wall of the small
intestine into the blood. The blood then
delivers the digested food to all our cells.
small intestine
What happens to undigested food?
COPY
Food which cannot be digested is passed to the
large intestine.
• Excess water is
Diagram of large intestine
absorbed from the
waste into the blood
by the walls
of the large intestine.
•The solid waste is
now called faeces. It
is stored in the
rectum and passes
out of the body via
the anus.
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Healthy Diet
H&W
To remain healthy, it is important to have a
balanced diet.
 This means eating the right quantities of
each of the food groups.
 Too much of one group, or not enough of
one group, may lead to:
- becoming overweight or underweight
- children not growing properly
- having less resistance to disease
- poor functioning of the body organs and
systems (eg the brain, kidneys, liver etc)
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My Day’s Diet
This is what I had to
eat and drink
yesterday.
H&W
Meal
Breakfast
Your teacher will
hand out this
sheet to be
completed in
class.
Snacks
Lunch
Snacks
Evening meal
Supper
What I ate and drank
How much I had
(e.g. 1 slice or 1 glass)
COPY AND COMPLETE
This is what I think about my day’s diet.
Good points
Bad points
Overall, do you think your diet was good or
bad ? Explain your answer.
H&W
Test your knowledge 7
1.
Which of these statements is true?
A balanced diet is
a. eating equal amounts of all the main food groups
b. eating the right amount of all the main food
groups
c. eating five portions of fruit and vegetables a day
2. State two possible outcomes of someone not eating
a balanced diet.
3. What is absorbed through the wall of the small
intestine?
4. What is absorbed through the wall of the large
intestine?
ANSWERS ON THE NEXT SLIDE
Answers
1.
2.
3.
4.
b
Become overweight, become
underweight, not growing, low
resistance to disease, poor
functioning of body organs, lack of
energy
Digested food
Water
HOMEWORK RESEARCH
TASK - A balanced diet
LITERACY
In order to remain healthy, grow and be
active, we need to eat the right balance of
all the different food groups. We call this a
balanced diet.
Your task
 Prepare a leaflet, made from A4 paper, a
poster or or a powerpoint on the meaning
and importance of a balanced diet.
 Include information on the health risks of an
unbalanced diet.
H&W
Literacy Outcomes
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LITERACY
Throughout the writing process, I can review and edit
my writing independently to ensure that it meets its
purpose and communicates meaning clearly at first
reading.
LIT 4-23a
I can use a range of strategies and resources
independently and ensure that my spelling, including
specialist vocabulary, is accurate.
LIT 4-21a
I enjoy creating texts of my choice and I am
developing my own style. I can regularly select
subject, purpose, format and resources to suit the
needs of my audience.
LIT 4-20a