The Breathing System
Chapter 5
Respiration
Respiration is the breakdown of food to give
energy.
Food + Oxygen  Energy + Carbon Dioxide + Water
Vapour
This reaction is called aerobic respiration
because it involves oxygen.
• The breathing system involves taking in the
Oxygen required and giving out Carbon Dioxide
and water vapour.
Experiment To show that
respiration produces energy.
1) Set up apparatus as shown
in diagram.
2) Over a week, record the
temperature in each flask.
Result
• The temp will have risen
in the flask containing the
live seeds but there will be
no change in temp in the
flask containing the boiled
seeds
Experiment. To show that respiration
produces CO2
1) Set up apparatus as shown in
diagram.
2) In test tube A are woodlice.
3) In test tube B are no woodlice.
• Result
The limewater in A will turn
milky
The lime water in B will not turn
milky.
The woodlice released CO2
A
B
Experiment:To show that CO2 is a
product of aerobic respiration in plants
Experiment: To show that respiration
produces water vapour.
1) Dry the surface of a mirror.
2) Breath on to the mirror to
produce condensation.
3) Test this with blue Cobalt
chloride paper.
Result
The blue cobalt chloride paper
turns a pink colour.
Water vapour is released during
respiration.
Experiment:To show that expired air has
more CO2 than inhaled air.
1) Breath in through tube X. Note
how long it takes the limewater
to turn milky
2) Breath out through tube Y Note
how long it takes the limewater
to go milky.
Result
It takes longer for the limewater in
X to go milky. There is more CO2
in the air we breath out than in the
air we breath in.
The Breathing System
The functions of the breathing system are:
• To take in Oxygen
• To excrete Carbon dioxide gas and Water
vapour.
• Inhalation is breathing in.
• Exhalation is breathing out.
Parts of the breathing system
Larynx
Rings of cartilage
Trachea
Right Bronchus
Rib cage
Bronchiole
Intercostal
muscles
Alveoli
Diaphragm
Lungs
Healthy lung
Breathing system
 Larynx (voice box)-allows us to make sounds.
 Trachea-passes air to lungs.
 Rings of Cartilage-keep airways open
 Bronchus-air carried from trachea to lungs
 Bronchioles-tiny tubes taking air to alveoli
 Alveoli-tiny air sacs where gaseous exchange takes
place
 Diaphragm-a sheet of muscle that moves down to
draw air into the lungs and to expel air out of the
lungs.
Taking a breath
When taking a breath:
 The diaphragm pulls downwards
 The rib cage expands
Bell jar model
 The bell jar model
demonstrates how the
diaphragm works.
 If you pull down the
rubber
sheet(diaphragm)
what will happen to
the balloons(lungs)?
Gaseous exchange
 Gaseous exchange
takes place in the
alveoli.
 The walls of the
alveoli are only 1 cell
thick and each
alveolus is
surrounded by tiny
blood vessels called
capillaries.
 Oxygen moves from
the alveolus into the
blood.
 Carbon Dioxide and
water vapour move
from the blood into
the alveoli and then
are breathed out
Gaseous exchange occurs
in the alveolus.
The effects of smoking
Smoking is harmful to the
breathing system.
• It can cause lung cancer,
bronchitis and
emphysema.
• It can also cause heart
attacks and can lead to
stunted growth of a baby.
• It causes bad breath
The cotton wool becomes
discoloured as the cigarette
smoke is drawn through it
Emphysema + Lung cancer
Why Do I Yawn?
When you are sleepy or drowsy the lungs do
not take enough oxygen from the air. This
causes a shortage of oxygen in our bodies.
The brain senses this shortage of oxygen
and sends a message that causes you to take
a deep long breath---a YAWN.
Why Do I Sneeze?
Sneezing is like a cough in the upper
breathing passages. It is the body's way of
removing an irritant from the sensitive
mucous membranes of the nose. Many
things can irritate the mucous membranes.
Dust, pollen, pepper or even a cold blast of
air are just some of the many things that
may cause you to sneeze.
• .
What Causes Hiccups?
Hiccups are the sudden movements of the diaphragm.
It is involuntary --- you have no control over hiccups, as
you well know. There are many causes of hiccups. The
diaphragm may get irritated, you may have eaten to fast,
or maybe some substance in the blood could even have
brought on the hiccups