UNIT 12 :Respiratory System
1. Look at the picture below.
2. Is it right or wrong to smoke inside the house where people are?
3. How does smoke affect the health of people?
4. What would you advise people who smoke in public places?5. Predict what you are going to learn in this unit.
12.1 The human respiratory system and its function
Find out
1. The main function of human respiratory system .2. The various organs of the human respiratory system.
Activity 12.1 Investigating the main function of the
respiratory system
1. Take a deep breathe and note the time on the clock or wrist
watch.
2. Close your mouth and nose tightly and hold onto your breathe.
How long can you stay without breathing? What does this tell
you about breathing?
The main function of respiratory system is to transport fresh air(
oxygen) into the lungs and remove waste air (carbondioxide) out of the lungs.
Identification of organs of the respiratory system
Activity 12.2 Identifying organs of the respiratory system
1. Look at the picture below.2. Draw and label the human respiratory system in your notebook.
The main parts of the human respiratory system are the nose,trachea lungs (windpipe), bronchi and the diaphragm.
Table 12.1: Parts of respiratory system and their functions
12.2 Mechanism of respiration (Breathing in and out)
Find out
1. How the human respiratory system operates.2. The process of breathing in and breathing out in human beings.
Activity 12.3 Investigating the mechanism of the
respiratory system
1. Place your hands on both sides of your chest. Take a deep breath.
What happens to your chest?
2. Repeat this several times and note what happens.3. Interpret your findings about breathing process.
Activity 12.4 Experiment to demonstrate how
respiratory system works
What you will need
Bell jar, two balloons, rubber stopper, Y-shaped glass tube, rubber sheet,
string.1. Set up the things above as shown in the picture below.
2. What do you think the following parts represent in the respiratory
system?
a) Bell jar
b) Balloons
c) Rubber sheet
d) Y-shaped tube
3. Pull down the string tied on the rubber sheet. What happens to
the balloons?
4. Release the string. What happens to the balloons?
5. Repeat steps 3 and 4 several times as you note what happens.
6. How do you think the findings in this experiment relate to theworking of the breathing system?
Mechanisms of breathing
Respiration refers to the act of breathing in / inhalation / inspirationand breathing out/ exhalation / expression.
• The bell jar represents chest cavity, Y-shaped tube represents the
trachea and bronchi, the balloons represents the lungs and the rubber
sheet represents the diaphragm.
Breathing in ( inhalation/ inspiration)
• When the rubber sheet is pulled downwards, the volume inside the
bell jar increases.
• The balloons become inflated( air rushes into the ballons). This issimilar to what happens during breathing in.
• When the sheet is released, the volume inside the bell jar reduces.
Air is pushed out of the balloons and they become deflated. This is similar to what happens during breathing out.
Table 12.2: What happens during (inhalation) and breathing out(exhalation)
12.3 Good health practices and behaviours for a
healthy respiratory system
Find out1. Care of the respiratory system.
Activity 12.5 Experiment to demonstrate the
danger of smoking cigarette
What you will need
• Transparent plastic bottle with cap
• Tissue paper • Rubber band
• Cigarette • Match box
• Nail • Biro-pen casing with cap
• Water
1. Make a hole at the bottom of the plastic bottle. Insert the biropen casing as shown below. Ensure that the bottle top is on.
2. Fill the bottle almost three-quarter way with water.
3. Take the cap off the bottle, make a hole then insert the piece ofcigarette.
4. Screw the bottle cap into the bottle with the cigarette filter inside
the bottle.
5. Light the cigarette using the match stick and match box.
6. Remove the cap of the biro pen casing to let the water out asshown below and observe what happens.
7. Once all the water is drained out of the bottle, remove the bottle
cap and wrap the tissue paper round the mouth of the bottle. Tie
it using the rubber band.
8. Blow air through the biro pen using the bottom of the bottle asshown below.
Why do you think this is important?
9. Unwrap the tissue paper and observe it carefully. What can you
see?
10. Discuss the results of this experiment with your friends. Relate
your findings here to what happens to the lungs when you smoke.
11. Based on the results of this experiment, do you think smoking is good or bad for our health?
Ways of taking care of the respiratory system include:
• Avoiding smoking or excessive driving of alcohol to
ensure healthy lungs.
• Eating a vitamin- rich diet
• Seeking immediate medical care in case of a respiratory problem.
• Exercising regularly to strengthen respiratory muscles.
• Drinking plenty of water.
• Avoid refined sugar, pasta or dairy products.
• Avoiding inhaling unknown or dangerous substances or
chemicals.
• When spraying chemicals in the house or any other place,
always wear protective clothing, for example, a gas mask.• Developing good eating habits
12.4 Diseases of the respiratory system
Find out
1. The various diseases that affect the respiratory system.2. What are their signs and symptoms?
Activity 12.6 Investigating the diseases of the
respiratory system
1. Using search engine, find out about diseases of the respiratory
system.
2. Write down your findings in your exercise book.
Common diseases of the respiratory system include:
• Tuberculosis (TB)
• Whooping cough
• Asthma
• Bronchitis• Pneumonia
Table 12.3 Signs and symptoms of the respiratory diseases and theircontrol measures
12.5 Suffocation
Find out
1. What suffocation is.
2. The cause of suffocation.3. First aid for suffocation.
Activity 12.7 Investigating the causes and
first aid suffocation1. Look at the picture below.
2. Discuss what happened to the people in the picture above.
If a person does not get enough air into the lungs, he/she suffocates.
Note: Suffocation may lead to death.
a) Causes of suffocation
• Choking - this is the blocking of the windpipe by food or other
materials. It prevents smooth flow of air into the lungs.
• Drowning – when we drown, the water prevents air from
reaching our lungs. We therefore suffocate.
• Carbondioxide inhalation.
• When a place is so hot that you cannot breathe easily you maysuffocate.
b) First aid for suffocation
In case of suffocation, you should do the following:
• For all the victims, loosen the clothing surrounding the neck, move
the victim to an open place with plenty of fresh air.
• Gently slap between the shoulder blades in case of chocking.• Perform abdominal thrusts.
• If the person is unconscious, lie them on a flat floor, clear the airways
and perform chest compressions.
• In case of drowning, tilt the victim towards one side with the head
down.
• If breathing has stopped, mouth to mouth resuscitation should begiven.
Self –Test 12.1
1. Which four practices would help to prevent respiratory problems
in human beings?
2. Name four respiratory diseases.
3. What causes suffocation?4. Describe the procedure you will use to help a suffocated person.
UNIT TEST 12
1. A human being without a respiratory system is as good as a car
without fuel. Explain this statement.
2. Explain the following observations:
a) Your heart rate increases when you do exercise such as running.
b) You cannot hold your breathe for more than five minutes.
3. Describe what happens to the chest and lungs during:
a) breathing in.
b) breathing out.
4. Dust particles and germs are trapped by the _______ and
___________ in the nostrils. Why is this important?
5. The _______________ is a sheet of muscles that separates the
chest cavity from the abdomen.
6. What do the parts shown in the breathing model below representin human respiratory system?
7. During breathing out, the waste gas called _____________
moves from the blood into the air sacs, after which it is breathed
out. On the other hand ______________ gas moves from the air
inside the air sacs into the blood.
8. Inspiration is to _________ as expiration is to __________
9. Which one of the following organs is not involved in breathing?
A. Diaphragm B. Bronchioles
C. Oesophagus D. Wind pipe
10. Describe an experiment you would use to show dangers of
smoking to members of your class.
11. How would you ensure that your respiratory system remainshealthy.