View
229
Download
6
Category
Preview:
Citation preview
© Boardworks Ltd 20061 of 28
The Respiratory System
© Boardworks Ltd 20061 of 28
These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page.
This icon indicates that the slide contains activities created in Flash. These activities are not editable.
For more detailed instructions, see the Getting Started presentation.
KS4 Physical
Education
© Boardworks Ltd 20062 of 28
Le
arn
ing
ob
jecti
ves
© Boardworks Ltd 20062 of 28
Learning objectives
The structures of the respiratory system and their
functions
The mechanisms of breathing
How gases are exchanged during breathing
The composition of inhaled and exhaled air
The different measurements of lung capacity and
breathing
The effects of exercise on the respiratory system
What is meant by aerobic and anaerobic respiration
The oxygen debt.
What we will learn in this presentation:
© Boardworks Ltd 20063 of 28
The respiratory system
© Boardworks Ltd 20064 of 28
The respiratory system
© Boardworks Ltd 20065 of 28
The nasal passages and lungs
Air is drawn into the body via the nose or mouth.
There are advantages to breathing through your nose:
Air then travels through the larynx, trachea (windpipe),
bronchi (one bronchus to each lung) and bronchioles to
the alveoli, where oxygen passes into the bloodstream.
the air is warmed so that it is closer to
body temperature
tiny hairs and mucus in the nose filter
the air, preventing larger dust and
pollen particles reaching the alveoli
mucus moistens the air, making it
easier for the alveoli to absorb.
© Boardworks Ltd 20066 of 28
When you breathe in:
intercostal muscles between
the ribs contract, pulling the
chest walls up and out
the diaphragm muscle
below the lungs contracts and
flattens, increasing the size of
the chest
the lungs increase in size,
so the pressure inside them
falls. This causes air to rush in
through the nose or mouth.
Mechanisms of breathing – inspiration
Diaphragm
contracts and
moves down
Intercostal
muscles pull ribs
up and out
© Boardworks Ltd 20067 of 28
Mechanisms of breathing – inspiration
© Boardworks Ltd 20068 of 28
Mechanisms of breathing – expiration
When you breathe out:
Intercostal muscles between
the ribs relax so that the chest
walls move in and down.
The diaphragm muscle below
the lungs relaxes and bulges up,
reducing the size of the chest.
The lungs decrease in size, so
the pressure inside increases
and air is pushed up the trachea
and out through the nose or
mouth.Diaphragm
relaxes and
bulges up
Ribs move in
and down
© Boardworks Ltd 20069 of 28
Mechanisms of breathing – expiration
© Boardworks Ltd 200610 of 28
Gas exchange at the alveoli
The alveoli are bunches
of tiny air sacks inside
the lungs.
Each individual sack is
called an alveolus.
When you breathe in,
they fill with air.
The alveoli are covered in tiny capillaries (blood vessels).
Gases can pass through the thin walls of each alveolus and
capillary, and into the blood stream.
Gases can also pass from the blood stream, into the alveolus.
© Boardworks Ltd 200611 of 28
Gas exchange at the alveoli
© Boardworks Ltd 200612 of 28
Composition of inhaled and exhaled air
GasAmount in
inhaled air
Amount in
exhaled air
Oxygen
Carbon dioxide
Nitrogen
Water vapour
17%
3%
79%
Large amount
21%
Very small amount
79%
Small amount
Why does mouth-to-mouth resuscitation work?
What are the main differences between
inhaled and exhaled air?
© Boardworks Ltd 200613 of 28
Measuring breathing
Tidal volume is the amount you breathe
in and out in one normal breath.
Residual volume is the amount of air left in your lungs
after you have breathed out as hard as you can.
Minute volume is the volume of air
you breathe in one minute.
Respiratory rate is how many
breaths you take per minute.
Vital capacity is the maximum volume of air you can
breathe out after breathing in as much as you can.
© Boardworks Ltd 200614 of 28
Measuring breathing
© Boardworks Ltd 200615 of 28
Measuring breathing
© Boardworks Ltd 200616 of 28
Calculating minute volume
Question
If you breathe 14 times in one minute (respiratory rate)
and you breathe 0.5 litres in each breath, what is your
minute volume?
Answer:
Minute volume = 14 × 0.5 litres
= 7.0 litres
Remember:
You can calculate a person’s minute volume by multiplying
the volume of air they breathe in one breath, by their
respiratory (breathing) rate.
Minute volume is the volume of air
you breathe in one minute.
© Boardworks Ltd 200617 of 28
Breathing during exercise
During exercise the muscle cells
use up more oxygen and
produce increased amounts of
carbon dioxide.
Your lungs and heart have to
work harder to supply the extra
oxygen and remove the carbon
dioxide.
Your breathing rate increases and
you breathe more deeply.
Heart rate also increases in order
to transport the oxygenated blood
to the muscles.
© Boardworks Ltd 200618 of 28
Breathing during exercise
Muscle cell respiration increases – more
oxygen is used up and levels of CO2 rise.
The brain detects increasing levels of CO2 – a
signal is sent to the lungs to increase breathing.
Breathing rate and the volume of air in
each breath increase. This means that
more gaseous exchange takes place.
The brain also tells the heart to beat
faster so that more blood is pumped
to the lungs for gaseous exchange.
More oxygenated blood gets to the
muscles and more CO2 is removed.
© Boardworks Ltd 200619 of 28
Breathing changes during exercise
During rest During exercise
Respiratory rate 14 breaths/ minute 32 breaths/ minute
Volume per
breath0.4 litres 2.4 litres
Minute volume ? ?
Look at these statistics for a 16 year-old athlete:
Calculate the athlete’s minute volumes
during rest and exercise.
Rest minute volume = 5.6 litres
Exercise minute volume = 76.8 litres
© Boardworks Ltd 200620 of 28
The effects of exercise on lung structures
The respiratory muscles (the
diaphragm and intercostals) get
stronger, so they can make the
chest cavity larger.
This larger chest cavity means
more air can be inspired, therefore
increasing your vital capacity.
More capillaries form around the alveoli,
so more gaseous exchange can take place.
In the long-term, regular exercise strengthens
the respiratory system.
Gas exchange can now take place more
quickly meaning exercise can be maintained
at a higher intensity for longer.
© Boardworks Ltd 200621 of 28
Respiration
Glucose from food is used to fuel exercise.
Respiration is the process that takes place in living
cells which releases energy from food molecules.
Waste products,
including carbon dioxide,
are produced as a result of
the chemical reactions. These
must be removed and excreted.
glucoseoxygen
energy
respiration
Oxygen is required to ‘break down’
the glucose to produce energy.
This energy is used to make
muscles contract.
© Boardworks Ltd 200622 of 28
Aerobic respiration
Aerobic exercise can be maintained for long periods
without the performer getting breathless or suffering
muscle cramps. Moderate activities like walking,
jogging, cycling and swimming use aerobic respiration.
There are two different types of respiration.
When you exercise at a steady, comfortable rate, the
cardiovascular system is able to supply the muscles with
all the oxygen they need.
Under these conditions, aerobic respiration takes place.
glucose + oxygen energycarbon
dioxide+ + water
© Boardworks Ltd 200623 of 28
Aerobic respiration
© Boardworks Ltd 200624 of 28
Anaerobic respiration
When you exercise at a high intensity, the cardiovascular
system cannot supply enough oxygen to the muscles.
Under these conditions, anaerobic respiration takes place.
With no oxygen available, glucose is burned to produce
energy and lactic acid.
Lactic acid is a mild poison. As it builds up, it causes muscle
pain and eventually cramp.
Short, intense activities like sprinting, weightlifting, jumping
and throwing use anaerobic respiration.
glucose energy + lactic acid
© Boardworks Ltd 200625 of 28
Oxygen debt
After anaerobic activity, oxygen is
needed to neutralize the lactic acid.
This is called an oxygen debt. It is
repaid after exercise.
The oxygen reacts with the lactic
acid to form CO2 and water.
Rapid and deep breathing is needed
for a short period after high intensity
exercise in order to repay the debt.
This also helps to remove the
carbon dioxide which accumulates
in the blood during intense exercise.
© Boardworks Ltd 200626 of 28
Anaerobic exercise
© Boardworks Ltd 200627 of 28
Exam-style questions
1. Describe the passage of oxygen from the nasal passages
to the bloodstream.
2. David goes jogging once a week for 45 minutes.
David tries to increase his pace. He finds that he is forced
to stop running and breathe hard for several minutes.
a) List two differences between the air that David
inhales and the air that he exhales while jogging.
b) What two substances are used by David’s body
cells to produce energy? What are the products of
this reaction?
c) Explain why David had to stop.
d) How did breathing hard help him to recover?
© Boardworks Ltd 200628 of 28
Can you remember all these keywords?
Larynx
Trachea
Bronchus / Bronchi
Bronchioles
Alveoli
Diaphragm
Intercostal muscles
Oxygen uptake
Tidal volume
Respiratory rate
Minute volume
Vital capacity
Residual volume
Aerobic respiration
Anaerobic respiration
Oxygen debt
Lactic acid
Recommended