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Body Systems
Digestion
Digestion
• Digestion is the breakdown of large
insoluble molecules into small soluble
molecules to allow absorption into the
blood stream through the small intestine.
Organs of the Digestive System
/Gullet
The Role of the Mouth
• Digestion starts in the
mouth
• Teeth are responsible
for the mechanical
breakdown of food.
• When we chew food it is
physically broken up
into smaller pieces
Oesophagus
• Oesophagus (gullet)
is a muscular tube
that connects the
back of the mouth to
the stomach.
Starter
• Define digestion.
• Name the different parts of the digestion
system.
Role of the Stomach
• Food is churned in the stomach
by the contraction of muscles to
mix the food with the stomach
acid.
• Food is churned for several
hours before being passed into
the small intestine
Role of the Small Intestine
• When food leaves the stomach and
passes into the small intestine, digestion is
completed.
• The soluble molecules produced by
digestion then pass across the small
intestine wall (absorbed) and enter the
bloodstream.
The Large Intestine
• Water & salts are
absorbed here.
• Indigestible
material stored in
the rectum.
• Then semi-solid
faeces eliminated
through the anus.
Model Gut Experiment
Aim:
To investigate if glucose or starch molecules are
able to pass through the wall of the small intestine
(gut) using a model.
Method:
1. Soften the Visking tubing with hot water.
2. Tie 2 knots at end of the piece of tubing.
3. Pour glucose and starch solution into tubing .
4. Tie 2 knots at the top of the tubing.
5. Half fill a boiling tube with water.
6. Place the tubing into the test tube of warm water.
7. Test the water for presence of glucose (using
Clinistix strips) and for starch (using the iodine test),
leave for 10 minutes. Test again.
Starter
• Define digestion.
• Name the different parts of the digestion
system.
• What is the function of the large intestine?
Results:
The water was tested for the presence of glucose and
starch, the results were as follows…
Result of test
Food stuff
Glucose
Starch
Conclusion:
0 minutes
10 minutes
Results:
The water was tested for the presence of glucose and
starch, the results were as follows…
Result of test
Food stuff
0 minutes
Glucose
Clinistix
No change
Starch
Iodine test – no change
Conclusion:
10 minutes
Conclusion
• Glucose was found to have passed through the
visking tubing into the water.
• Since only starch and amylase enzyme were in
the bag at the beginning, then we must conclude
that the starch was broken down into glucose by
the amylase enzyme.
• The starch molecules are too large and insoluble
to pass through the walls of the tubing but the
glucose molecules are small and soluble and can
squeeze through.
• This demonstrates how digestion works,
enzymes break down large insoluble food
molecules into small soluble molecules that can
be absorbed into the bloodstream.
Digestion In Action
Aim:
To discover what must happen to starch in order
for it to pass through the small intestine (gut) wall.
Method:
1. Soften the Visking tubing with hot water.
2. Tie 2 knots at end of the piece of tubing.
3. Pour starch solution into tubing and add digestive juice.
4. Tie 2 knots at the top of the tubing - rinse with water.
5. Half fill a test tube with warm water.
6. Place the tubing into the test tube of water.
7. Immediately test for the water for the presence of
glucose (using Clinistix strips) and for starch (using the
iodine test), leave for 10 minutes. Test again.
Results:
The water was tested for the presence of glucose
and starch, the results were as follows…
Food stuff
Result of test
0 minutes
Glucose
strip:
Starch
Iodine test –
10 minutes
Conclusion:
• Can starch pass through tubing?
• What has the digestive juice (enzyme) done to the starch to
allow it to pass through the tubing?
• What do you think must happen to the starch to let it pass
through the wall of the small intestine into the blood?
Starter
• Name the different parts of the digestive
system.
• What is the function of the small intestine?
• How do enzymes work?
ENZYMES!
• Enzymes breakdown the food
during digestion.
• What are they?
• But how do they do it?
• What else do they do?
What is an enzyme?
• An enzyme is a biological catalyst.
• That means it speeds up reactions in living
things.
• So food would eventually break down by itself,
but it would take so long, we'd run out of
energy to do it!
• Enzymes are found in our digestive juices.
Starter
• Enzymes in the digestive system _____
_____ food so it can be absorbed across
the lining of the _____ ______ into the
bloodstream.
• Enzymes are biological _________ , they
________ up reactions in living things.
• Enzymes are found in our _______ juices.
• Different enzymes are needed to break
down ________ kinds of _____.
Some common body enzymes
Enzyme
Substrate
End product
Starch
Maltose
Amylase
Pepsin
Protein
Lipase
Fat
Amino acids
Fatty acids
& glycerol
ENZYMES- how do they work?
How do enzymes work?
• An enzyme works
on only one
reaction
• This is because of
its shape
Note: How Enzymes work
• Enzymes work by ______ and ______,
this means they only work on one reaction.
• Copy and complete the diagram of an
enzyme reaction
Enzyme activity and temperature
Experiment
Aim
To find out at which temperature the enzyme
pepsin breaks down albumen (a large
protein molecule) best.
Pepsin Experiment
Instructions
Add 5ml albumen and 3ml pepsin to 3 test tubes.
1) test tube 1 goes into water bath at 37oC.
2) test tube 2 goes into water bath 70oC.
3) test tube 3 goes into the ice bath.
MAKE UP YOUR SOLUTIONS QUICKLY AND PLACE IN ALLOCATED
BATH.
Leave for 15m at the different temperatures.
Examine the contents of the test tubes for
clearing.
Results
Draw a table of results.
What's going on in the test tube?
• Enzyme is BREAKING DOWN the protein
Conclusions
• The enzyme pepsin breaks down the
albumen protein best at ________.
• This is it's optimum (best) temperature,
because it is _____________.
Enzyme activity and pH
• As well as having an optimum
temperature, enzymes will also work best
at a certain pH.
• Different enzymes will work best at
different pH’s, although many body
enzymes work best at pH7.
• Can you think of anywhere in the body
where the optimum pH of an enzyme
might be different?
Activity:
• Investigating Enzymes – The effect of pH
on enzyme activity.
• Read the info sheet then work through the
notes box on the activity sheet.
• (remember the rules for drawing graphs)
Body Systems
Breathing
Breathing System
• The _____ are the organs involved in breathing.
• Breathing is the way in which ______ is taken into our
body cells and ____ ____ is removed from our body cells.
• When we breath ___ we take fresh air into our lungs.
• Our body gets rid of carbon dioxide when we breath ___.
Breathing System
• The lungs are the organs involved in breathing.
• Breathing is the way in which oxygen is taken into our
body cells and carbon dioxide is removed from our body
cells.
• When we breath in we take fresh air into our lungs.
• Our body gets rid of carbon dioxide when we breath out.
Breathing In and Out
Draw the table and headings ‘Breathing In’ and ‘Breathing Out’.
Rearrange the correct phrases in the correct order under the
correct headings.
Breathing In
Breathing Out
Contraction of Rib
Muscles
Contraction of
Diaphragm
Chest gets bigger
Air moves in
Chest gets smaller
Air moves out
Relaxation of
Diaphragm
Relaxation of Rib
Muscles
Breathing In and Out
Your table should look like this
Breathing In
Breathing Out
Contraction of Rib
Muscles
Contraction of
Diaphragm
Chest gets bigger
Relaxation of Rib
Muscles
Relaxation of Diaphragm
Air moves in
Air moves out
Chest gets smaller
Structure of lungs
Pathway of air
Trachea
Bronchi
Bronchioles
Air sacs
(alveoli)
Gas exchange in air sacs
• Oxygen moves into the bloodstream
from air sacs, to be carried round the
body.
• Carbon Dioxide moves out of the blood
into the air sacs, to be breathed out.
Breathing
Task: ‘Air Changes When Breathing In and Out’
•
Complete the table showing the air changes when
you breathe in and out P39 S Sc Book 2.
Gas
Quantity in the
air breathed in
Oxygen
21%
Carbon
dioxide
0.04%
nitrogen
79%
Water vapour
Quantity in the
air breathed out
varies
Air breathed in is also __________ in temperature than air breathed
out.
Transporting gases around the body
• The two gases involved in breathing
are _______________ and
____________ _______________.
• They are transported around the body
to and from cells by the body’s
transport system – The Bloodstream.
• The next set of lessons looks at how
blood circulates around the body.
The Circulatory System
in the Human Body
• Heart:
Pumps blood around
body
• Blood vessels:
Tubes that carry
blood to all parts of
body
Heart
• Made of:
muscle
• Job:
Pumps blood around
body
Structure of heart
Valves in the Heart
• 4 valves inside heart
• Each valve opens to
allow blood to pass in
correct direction
• Valve then closes to
prevent the blood
flowing backwards
in wrong direction
Heart beat sounds
• The sounds of valves
opening & closing
• Are heard using a
stethoscope
Write- The heart
• The heart is made of muscle and pumps blood
around the body.
• The heart muscle contracts and relaxes and blood is
pumped through the blood vessels around the
body.
• There are valves in your heart which make sure that
the blood always flows in the right direction.
• The closing and opening of these valves can be
heard as heart beats when you listen to someone’s
chest.
Quiz
• 1. What is the function (job) of the heart?
• 2. What type of tissue is the heart made
of?
• 3. How many chambers are in the heart?
• 4. How many valves are in the heart?
• 5. What is the job of the valves in the
heart?
Blood vesselsCarry blood around body
• 3 main types:
• Arteries
carry blood away from the
heart
• Veins:
carry blood towards the
heart.
• Capillaries: link up arteries with veins.
Blood vessels
• Artery divides into smaller
microscopic vessels called
capillaries
• Capillaries join up to make
larger vessel called a vein
• This linking between the blood
vessels can be viewed here:
http://www.bbc.co.uk/bitesize/s
tandard/biology/the_body_in_a
ction/the_need_for_energy/revi
sion/7/
Quiz
• What is the function of the heart?
• What type of tissue is the heart mainly made of?
• What type of blood vessel a) carries blood away
from the heart b) carries blood towards the heart
c) links arteries and veins?
• Name 2 substances that are carried by the blood
to the tissues.
• Name a substance that is carried by the blood
away from the heart.
Blood - 2 main jobs.
1 – Transport useful substances
2 – Protection from infection.
– Blood carries Nutrients such as oxygen and glucose,
these are transported to our organs and tissues;
– Blood carries Waste products such as carbon dioxide
and urea, these are taken away from our organs and
tissues.
– Blood is made up of different types of cells all floating in a
watery fluid called plasma.
– Watch the clip from Glow about blood
– https://www.twigonglow.com/films/blood-971/
Red Blood Cells
Platelets
White Blood Cells
Blood is composed of:
1. Plasma – watery, yellow fluid which carries cells and
dissolved substances e.g. food, hormones
2. Blood cells
a) Platelets - involved in protecting the body against
infection by clotting (clumping together) to seal up
cuts and wounds and prevent further blood loss and
to allow new skin to grow underneath (scab)
b) Red blood cells - carry oxygen
c) White blood cells - fight infection
(Stick in the diagram)
Red cells
platelets
White cells
Components of Blood
• Blood provides us with the means to get
_______ and ________to cells and to remove
__________ ________.
• Blood also plays a vital role in protecting the
body and fighting ___________.
• Blood is composed of _____ blood cells,
________ blood cells and _________that are
contained in a watery yellowish fluid called
_________.
• Each part of blood has its own specific role the
ensure the body functions effectively.
Role of Red Blood Cells (RBC)
• Their main function is to
carry oxygen around the
body.
• They are small and flexible
and can squeeze through the
tiniest capillaries to deliver
oxygen to your cells.
• Look at the tip of your little
finger, how small and
narrows will the capillaries
be?
Starter
• What type of blood vessel a) carries blood
away from the heart b) carries blood
towards the heart c) links arteries and
veins?
• What does blood comprise of?
• What is the function of white blood cells?
White Blood cells (WBC)
•White blood cells are part
of our Immune System.
•Their main function is to
fight infection and defend
against disease from
microorganisms like
Bacteria or Viruses
•There are two types of
WBC –
•1 -Those which eat
invaders.
•2 -those which produce
special antibodies to fight
invaders.
White blood cell soldiers!
• These WBC’s patrol
the body in the
bloodstream looking
out for invaders such
as bacteria and virus
particles.
• They wander
throughout the entire
body engulfing
bacteria & dead cells
breaking them down .
• Watch glow clip on
immune defence 1
• https://www.twigonglow.
com/films/immunedefence-part-1-1072/
Antibodies –
Special Immune Response!
•
Some WBC’s produce special cells
called antibodies. There are
thousands of different types of
antibodies because each one is
specific to deal with a certain type
of bacteria or virus.
•
These antibodies are special
chemicals that stick to the surface
of bacteria and viruses.
•
This causes the invaders to clump
together and so stop them moving
around the body.
•
Bacterial cells
clumping together
The clump of cells can then be
eaten up by other patrolling WBC’s.
Watch the glow clip
https://www.twigonglow.com/films/i
mmune-defence-part-2-1085/
Antibiotics – a helping hand for your immune system
https://www.twigonglow.com/films/antibiotics-1635/
Tonsils are badly swollen and infected.
Yellow, pus is visible.
This is bacterial tonsillitis
• Sometimes it can take a
while for your body to
produce enough antibodies
to fight off the infection.
• This can mean that you get
sick for a few days.
• Sometimes certain types of
bacterial infections need
special medicines called
antibiotics to help the
immune system get rid of
the invading bacterial cells.
• Some common bacterial
infections are:
• Tuberculosis, Urine
Infections, conjuctivitis,
infected throat – tonsillitis.
Viral Infections –
• Some types of infections
are caused by viruses.eg chicken pox, measles,
cold and flu.
• These CANNOT be
treated with antibiotics.
• The bodies immune
system must try to deal
with viruses on its own.
• Sometimes it is possible
to protect against viral
infection using an
injection called a
Vaccine.
Vaccine
• A vaccine contains a harmless copy of
certain types of viruses.
• It is injected into the body to and can
“fool” the body into the production of
antibodies without the symptoms of the
disease.
• This means if this type of virus does then
invade the body, the body already has
some specific antibodies to deal with it
quickly and so prevent you getting sick.
• The “flu jab” and some injections you get
as a baby like the MMR(measles, mumps
and ruebella), Polio drops, or as
https://www.twigonglow.com/f
teenagers the HPV vaccine (cervical
ilms/eradication-of-poliocancer) can help to protect against
1638/
certain types of viral infections.
Controlling Growth of Bacteria
• You already know that antibiotics can be
given to patients to help control the growth
of bacterial infections in the body.
• There are other ways of controlling the
growth of bacteria outside the body.
Investigation
• To examine the effect of alcohol hand
wash on the growth of bacteria.
Method
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Ensure all work surfaces have been wiped clean with disinfectant.
Collect 2 Petri dishes containing nutrient agar (DO NOT OPEN).
Label the base of one with your Name, Date and ‘bacteria swab
before washing’ and the second with Name, Date and ‘bacteria
swab after washing’ .
Use a cotton bud to swab across the palm of your hand.
Open the lid of your Petri dish labelled ‘bacteria before washing’
and rub the swab across the surface of the agar.
Replace lid and cellotape the plate closed at either end.
Wash your hands using the alcohol hand wash.
Swab your hands again with a clean cotton bud, open Petri dish
labelled ‘bacteria after washing’ and rub the swab across the
surface of the agar.
Replace the lid and cellotape the plate closed at either end.
Incubate your plates for 48 hours at 30oc.
Results
• Draw a diagram of the two plates,
remember to label ‘before’ and ‘after’
washing.
Conclusion
• Alcohol hand wash _____________ the
growth of bacteria.
Yeast - another microorganism
Yeast is a single celled fungus.
Cell Wall
Cell Membrane
Cytoplasm
Nucleus
Yeast cells budding
Yeast cells reproduce by budding:
Yeast Growth Rate
• Yeast can grow very quickly if they are
under the right conditions.
• Every 30 minutes, yeast cells will double
in number
• E.g. 2, 4, 8, 16, 32, 64, 128...
Yeast
• Yeast cells need ideal conditions to grow.
• A few of these conditions are:
• 1. Suitable temperature
• 2. Neutral pH
• 3. Supply of sugar
• Yeast cells can be grown in huge numbers in
large vessels called fermenters.
Fermentation Vessels
Investigation
Aim: To find out the best temperature for the
growth of yeast cells.
Growing Yeast on Agar
• Today you will carry out
a microbiology technique
to grow your own
cultures of yeast in a
Petri dish containing
nutrient agar.
• You will then incubate
them at 3 different
temperatures for 48
hours before checking to
see what the best
temperature for yeast
growth was.
Method
• Ensure all work surfaces have been wiped clean with disinfectant.
• Collect 3 Petri dishes containing nutrient agar (DO NOT OPEN)
• Label the bases with your Name, Date, Yeast Cells and the
temperature to be incubated (5oC, 25oC and 55oC).
• Use a syringe to measure 0.2ml of yeast solution, carefully open a
plate and add the yeast solution.
• Use a spreader to spread the yeast out evenly over the surface of
the agar.
• Replace lid and cellotape the plate closed at either end.
• Repeat the process with the other plates and then incubate at the
required temperature.
Results
Temperature of
Incubation (degrees
Celsius)
5 oC
25oC
55oC
Growth level of yeast
(low, medium, high)
Conclusion
• The best temperature for the growth of
yeast cells is ____________.
• At _______ and ________ temperatures
the growth of yeast cells is ___________.