THE RESPIRATORY
SYSTEM
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THE RESPIRATORY SYSTEM -- TEACHER
TEACHER NOTES
NOTES
What it does:
• Obtains oxygen from the air and makes it available to the rest of the body.
• Removes the waste product carbon dioxide from the body.
What body parts are involved:
•
•
•
•
•
•
mouth
nose
trachea
bronchus
bronchiole
alveoli
• lungs
What it looks like:
nose
mouth
trachea
bronchiole
left lung
alveoli
diaphragm
Alveoli showing direction
of blood circulation
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How it works:
• The cells in our bodies need oxygen to break down food that becomes energy. When cells break
down the food, the waste product is carbon dioxide. So, our bodies need a way of obtaining
oxygen and getting rid of carbon dioxide. The respiratory system is the way our bodies do this.
• Air enters the body through the mouth or nose by inhalation. The nose is best to inhale through
as there are hairs which help to trap dust particles. As the air enters the body it is warmed up
through the nasal cavity.
• Once air is inhaled, it moves through the trachea to the lungs. The trachea is a tube with cartilage
rings which help it to remain open at all times (unlike the oesophagus).
• The lungs are a pair of spongy bags inside the chest. At the lungs, the trachea splits into two
bronchi (single is bronchus), which splits into smaller bronchioli (single is bronchiole). The
bronchioli eventually lead to tiny air sacs called alveoli (single is alveolus).
• The alveoli look like tiny bunches of grapes. The outside of the alveoli are covered with capillaries.
It is here that the oxygen passes through the thin wall (one cell layer thick) of the alveoli to the
red blood cells within the capillaries.
• This blood, which is now loaded with oxygen (or, oxygenated), makes its way to the heart, which
pumps the oxygenated blood around to the rest of the body.
• When the blood ‘drops off’ the oxygen to the cells in the rest of the body, it also picks up carbon
dioxide. This carbon dioxide gets pumped through the heart and back to the lungs. The carbon
dioxide passes from the blood to the alveoli through the thin wall and is released from the body when
we exhale.
Other facts to know:
• The surface area of our lungs is about 35 times larger than the surface area of our skin. The huge
surface area allows the body to absorb oxygen and expel carbon dioxide efficiently.
• Without oxygen our cells die. This is why we need to breathe to survive.
• When we exercise our bodies require more energy. As a result our cells need more oxygen so
that they can produce enough energy. Hence, when we exercise, we breathe more rapidly.
• On average, we breathe around 13-17 times a minute. When we exercise, we breathe as many as
80 times per minute.
• To draw air in, lungs need to expand. Muscles around the ribs pull the chest up and out and a
domed sheet of muscle called the diaphragm pulls the lungs down.
• Every minute, we breathe in around 6 litres of air.
• There are around 300 million alveoli in a pair of lungs.
• The surfaces of the airways are protected by a slimy liquid called mucus. When we have colds, the
airways fill up with mucus and cause us to cough.
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• Smoking has the effect of irritating the airways and they fill up with mucus. The smoke also
weakens the tiny hairs (cilia) that waft the mucus out. This leaves lungs prone to infection
• Hiccups are caused by a sudden contraction of the diaphragm, dragging air into the lungs so quickly
that the vocal chords snap shut.
• The lungs are protected by the ribcage. The left lung is slightly smaller than the right lung to make
room for the heart.
• During breathing, dust, pollen, and other particles are swept into the respiratory tract. Most of
these are trapped by mucus or hairs, but the smallest ones find their ways into the lungs. They are
dealt with here by wandering cells called dust cells. Dust cells engulf these foreign invaders and
break them down to prevent them from clogging up the lungs.
• Hay fever is caused by an allergy to pollen (the most common form of hay fever is an allergy to
grass pollen) which enters the lungs.
• Asthmatics have oversensitive airways. An asthma attack is caused by the muscles surrounding the
bronchioles spasming and the tubes becoming swollen. Breathing through these narrow passages causes
wheezing and coughing as the asthmatic person gasps for breath.
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RESPIRATION ACTIVITIES
ACTIVITIES
Activity Title:
Level:
Resources Required:
Specific learning outcome:
Curriculum links:
Creating a model lung
Y5-Y6
Sticky tape
Plastic lemonade bottle with the bottom cut off
Balloons
Strong rubber bands
Students will understand how human lungs work
Health and Physical Education
Personal health and physical development
Science
Living world
Technology
Technological knowledge and understanding
Essential Skills
Communication, information, problem solving skills, social and
co-operative skills
Description:
1 Poke a balloon into the neck of the bottle. Catch the balloon neck and open around the neck of
the bottle. Attach securely with a rubber band.
2 Make a rubber sheet to attach to the bottom of the bottle by cutting the neck off the top of
another balloon. Cover the bottom of the bottle with this rubber sheet and attach securely with a
rubber band.
3 Explain that the bottle represents the diaphragm, and the balloon inside the bottle represents
the lungs.
4 Watch what happens when the diaphragm moves up and down (‘lungs’ will inflate and deflate).
NB this can be done as a demonstration, in groups, or as individuals depending on the level of
the students
rubber band
balloon
plastic bottle
rubber band
balloon
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Activity Title:
Level:
Building a spirometer
Y5-Y6
Resources/Apparatus Required: Large bowl of water
Large plastic bottle
Length of rubber tubing
Specific learning outcome:
Curriculum links:
Students will measure lung capacity
Health and Physical Education
Personal health and physical development
Science
Living world
Technology
Technological knowledge and understanding
Mathematics
Number, Measurement
Essential Skills
Communication, numeracy, information, social and
co-operative skills
Description:
1 Mark litres (in 250ml stages) on the large plastic bottle.
2 Fill it with water and place it upside down in the large bowl of water.
3 Insert the piece of rubber tubing so that one end is outside the water, and one goes through into
the inside of the bottle (see illustration below).
4 Breathe deeply and blow as much air as possible through the tube and into the container.
5 Pinch the tube and measure the lung capacity by reading the litres marked on the plastic bottle.
Plastic bottle
rubber tubing
Plastic container
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Activity Title:
Level:
Resources/Apparatus Required:
Specific learning outcome:
Curriculum links:
Ordering the air passages
Revision/reinforcement activity
Y3-Y6
Laminated pieces of cardboard with each of the following
words on them (alveoli, bronchiole, bronchus, nose, trachea)
Students will know the passage of air through the
respiratory system
Health and Physical Education
Personal health and physical development
Science
Living world
Essential Skills
Communication, information, problem solving, work and study
Description:
1 Hand the laminated cards with the words on them out to the students (working in groups or
as individuals).
2 Students’ job is to list the air passages and lung structures in the order in which air will pass
through them when it is being breathed in.
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Activity Title:
Level:
Resources/Apparatus Required:
Specific learning outcome:
Curriculum links:
Breathing and exercise
Starter activity
Y3-Y6
Stop watches
Students will discover the effect that exercise has on breathing
Health and Physical Education
Personal health and physical development
Science
Living world
Mathematics
Measurement
Essential Skills
Communication, information, problem solving, work and study
Directions:
1
2
3
4
Have the students measure how many breaths they breathe per minute.
Get the students to carry out exercise (eg running on the spot for 1 minute, running 100m, etc).
Get the students to remeasure their breathing rates.
Follow with class discussion about why we breathe more when we exercise.
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Activity Title:
Level:
Breathing in and Breathing out
Revision activity
Y4-Y6
Resources/Apparatus Required: Laminated cards with phrases on them
Specific learning outcome:
Curriculum links:
Students will know the process of breathing in and
breathing out
Health and Physical Education
Personal health and physical development
Science
Living world
Essential Skills
Communication, information, problem solving, work and study
Directions:
Get the students to put two headings on their page: ‘Breathing in’ and ‘Breathing out’. Then, get
them to put the following phrases under the appropriate heading:
• Ribs move up and out
• Ribs move down and in
• Diaphragm is domed
• Diaphragm is flat
• Volume is bigger
• Volume is smaller
• Pressure increases
• Pressure decreases
• Air is drawn in
• Air is forced out
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Activity Title:
Level:
A closer look at pollen
Y4-Y6
Resources/Apparatus Required: Microscopes
Pollen from flowers (irises are good to use)
Specific learning outcome:
Curriculum links:
Students will discover why pollen affects the way we breathe
Health and Physical Education
Personal health and physical development
Science
Living world
Technology
Technological knowledge and understanding
Essential Skills
Communication, information, problem solving, social and
co-operative skills, physical skills
Directions:
1 Ask how many of the students have hay fever. Ask them if they know what causes hay fever
(why it is called hay fever? is there any particular time of the year it gets worse? etc.). Establish that
the cause of the allergic reaction is pollen when it is breathed into the lungs.
2 Get the students to collect pollen from the flowers and examine them under a microscope.
3 Get them to draw what they see and then discuss the different shapes.
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Activity Title:
Dust in the air
Resources/Apparatus Required: White ceramic tiles (1 between 2 students)
Petroleum jelly
Specific learning outcome:
Curriculum links:
Students will discover how much dust is in the air that
they breathe
Health and Physical Education
Personal health and physical development
Science
Living world
Essential Skills
Communication, information, work and study
Directions:
1 Get the students to cover the ceramic tiles with a thin layer of petroleum jelly and leave them in
various places.
2 Get the students to check the tiles at 2 day intervals and write down their observations.
3 Compare the state of the tiles at the end of 10 days and discuss how much dust is in the air and
how it differs from place to place. Discuss possible reasons why.
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Activity Title:
Level:
Building a respiratory system
Revision activity
Y5-Y6
Resources/Apparatus Required: A variety of everyday objects eg different shaped boxes, plastic
bags, plastic containers, cardboard tubes, empty bottles,
cardboard, etc
Specific learning outcome:
Curriculum links:
Students will build their own respiratory system
Health and Physical Education
Personal health and physical development
Science
Living world
Essential Skills
Communication, information, problem solving,
self-management and competitive skills, social and co-operative
skills, work and study
Directions:
1 Organise the class into groups of 3-4 and instruct them that they are going to build their own
respiratory system using the items that are in front of them.
2 Get the students to work as fast as they can to produce the most detailed and complete
respiratory system possible. Ensure that each group is able to explain what each part is and
what it does.
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