5
Module 6
Science and Health
THE RESPIRATORY SYSTEM
A DepEd-BEAM Distance Learning Program supported by the Australian Agency for International Development
To the Learner
We need air to live. The air for life is called oxygen. We could not
live without oxygen. In contrast, we do not need carbon dioxide.
Carbon dioxide is a waste produced in our body. It is harmful; hence,
it must be given off.
How does oxygen get into our body? Likewise; how does carbon
dioxide get out from our body? Which body system is responsible for
taking in oxygen and giving out carbon dioxide?
Let’s Learn This
When you finish this module, you will be able to identify the
respiratory system and its major parts.
Let’s Try This
Riddle Time: Who am I?
Inhale these scrambled words. Exhale the answers to the riddles.
1. I warm and clean the air you breathe. SNOE __________
2. There are 300 millions of me in your lungs.
RAI SCAS _________________
(two words)
3. I leave your body when you breathe out. RONBAC DOXEIDI
(two words)
______________________
4. I am a long tube connecting your mouth to your lungs.
RATHCAE ______________
5. I go through the air sacs and into the blood. YXGONE __________
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Let’s Study This
Oxygen and carbon dioxide occur in alveoli of the lungs
Your respiratory system is made of body parts that help you
breathe in oxygen and breathe out carbon dioxide. It includes these
organs: nasal cavity, pharynx, larynx, trachea, bronchitis and lungs.
Each organ has a definite function to perform.
Air enters your body through the two nostrils. The nostrils are
the opening in your nose. There are hair inside your nostrils which
traps dust from the air. Your nostrils lead to a cavity called the nasal
cavity. In the nasal cavity, air gets moistened and warmed. The nasal
cavity is lined by glands that produce sticky mucus. Dust, pollen and
other materials are trapped by the mucus. This trapping of the air
impurities helps in filtering the air you breathe.
Tiny hairlike
structures called cilia are found in the nasal cavity. These cilia move
the mucus and trapped materials to the back of the throat where they
can be swallowed.
The nasal cavity leads to the tube like passageways for both food
and air. The pharynx is found between your nasal cavity and your
esophagus. A flap of tissue is found at the end of the pharynx. This is
called the epiglottis. The epiglottis closes over your larynx when you
SWALLOW. In this way, food or liquid is not allowed to enter your
larynx by accident. Instead, the food or liquid goes to your esophagus.
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Between the pharynx and trachea you can find the larynx. Your
vocal cords are attached to the larynx. Your vocal cords produce
sounds when you speak.
Below the larynx is a tube about 12 cm long. This is the trachea.
The trachea is composed of C-shaped rings of cartilage to keep it open.
Mucous membrane and cilia line the trachea. They trap bacteria, dust
and pollen.
The trachea branches out into two short tubes called the bronchi
(singular: bronchus).The bronchi carry air into the lungs. The bronchus
within each lung branches into a smaller and tubes. The smallest tubes
are called the bronchioles. Tiny-walled sacs called alveoli cluster at the
end bronchiole. The alveoli are arranged in grape-like cluster
surrounded by the capillaries. Between the alveoli and capillaries the
exchange of oxygen and carbon dioxide takes place. As this happens,
oxygen enters your body when you breathe in, or inhale. In contrast,
carbon dioxide leaves your body as you breathe out or exhale.
Let’s Do This
Examine the parts of the respiratory system as shown in the diagram.
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Let’s Do More
Identify the part of the respiratory system which is being referred
to. Write the name of that part before the number.
______________ 1.
Closes over your larynx when you swallow.
______________ 2. Two short branches at the end of the trachea that
carry air into the lungs.
______________ 3.
Cluster of tiny thin walled sacs found at the end of
each bronchioles.
______________ 4.
Substance produced by the lining of the nasal
cavity.
______________ 5.
Tiny hair-like structures that trap bacteria in the
trachea.
______________ 6.
A tube made up of C-shaped rings of the cartilage.
______________ 7.
Opening of the nose that leads to the nasal cavity.
______________ 8.
A tube-like passage for both food and air.
______________ 9.
Produces vocal sounds.
______________ 10. Compose of alveoli arranged in grape-like clusters.
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Let’s Remember This
• The respiratory system is made up of different organs
responsible for making the body take in oxygen and
give off carbon dioxide and moisture.
• The main function of the nose and the nasal cavity is
to filter, warm, and moisten the air that enters the
body.
• The pharynx is a part of the throat located just behind
the mouth which serves as a passageway for both and
air.
• The larynx, also called the voice box, contains the
vocal cords. The vibration of the vocal cords produces
sound.
• The epiglottis is a flexible flap of tissue located at the
opening of the larynx. It closes the larynx. It closes
the larynx when you swallowing causes choking.
• The nose, nasal cavity, pharynx, larynx, and trachea
serve as passageway of air getting into the body.
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Let’s Test Ourselves
Match column A with column B by writing the letter of the correct
answer on the space provided for.
_____ 1.
_____ 2.
_____ 3.
_____ 4.
_____ 5.
_____ 6.
_____ 7.
_____ 8.
_____ 9.
_____10.
A
A muscle that controls breathing.
A smaller extension of the bronchi.
The upper part of the throat that carries
air into the respiratory tract.
Opening in the nose.
A leaf shaped cartilage that covers
the larynx during swallowing.
Air sacs in the lungs.
Upper end of the trachea which
is also known as the voice box.
Two large main branches of the trachea.
A tube that goes down the lungs
and is also known as the windpipe.
Gas given off during exhalation.
d.
e.
B
larynx
trachea
carbon
dioxide
alveoli
epiglottis
f.
g.
pharynx
diaphragm
h.
i.
bronchioles
nostrils
j.
bronchi
a.
b.
c.
Science Fact File
™
Do you know that each adult lung weighs .45 kilograms.
™
A normal person takes in about 11,3000 liters of air each day.
™
Air going into our lungs contains about 21% oxygen and practically
no carbon dioxide.
™
Air leaving our lungs contains about 16% oxygen and over 4%
carbon dioxide.
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Answer Key
Let’s Try This
1.
2.
3.
4.
5.
1. alveoli
2. nostrils
3. mucus
4. pharynx
5. epiglottis
6. trachea
7. larynx
8. cilia
9. bronchioles
10.bronchi
Nose
Air sacs
Carbon dioxide
Trachea
oxygen
Let’s Do This
1.
2.
1.
2.
3.
4.
5.
6.
Let’s Do More
Let’s Test Ourselves
nasal cavity
pharynx
epiglottis
trachea
lungs
bronchioles
diaphragm
bronchial tubes
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
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g
h
f
i
e
d
a
j
b
c