9

Science
Quarter 1 – Module 1:
Respiratory and Circulatory
Systems, Working with other Organ
Systems
Science – Grade 9
Quarter 1 – Module 1: Respiratory and Circulatory Systems, Working with other Organ
System
First Edition, 2020

Republic Act 8293, section 176 states that: No copyright shall subsist in any work of
the Government of the Philippines. However, prior approval of the government agency or office
wherein the work is created shall be necessary for exploitation of such work for profit. Such
agency or office may, among other things, impose as a condition the payment of royalties.

Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names,
trademarks, etc.) included in this module are owned by their respective copyright holders.
Every effort has been exerted to locate and seek permission to use these materials from their
respective copyright owners. The publisher and authors do not represent nor claim ownership
over them.

Published by the Department of Education

Development Team of the Module

Writers: Queeny F. Coronel
Editors: Jherra Janina G. Gono, Romel S. Villarubia
Reviewers: Honey Lynne A. Boyles, Romel S. Villarubia
Illustrator: Queeny F. Coronels
Management Team: Dr. Josephine L. Fadul - SDS
Dr. Christine C. Bagacay – OIC ASDA
Dr. Maria Fe D. Sibuan – OIC CID Chief, EPS in Mathematics
Dr. Honey Lynne A. Boyles – EPS in Science
Dr. Lorna C. Ragos – LRMDS Supervisor
Jecson L. Oafallas – Project Development Officer II
Romel S. Villarubia – Junior High School Focal Person

Printed in the Philippines by ________________________

Department of Education – Region XI

Office Address: E-Park, Apokon, Tagum City

Telefax: (084)-216-3504

E-mail Address: http://deped.tagumcity.gov.ph

 9

Science
Quarter 1 – Module 1:
Respiratory and Circulatory
Systems, Working with other
Organ Systems
Introductory Message
For the learner:
This Module is designed primarily to help you, learners, continue
learning despite the present situation. This effort of DepEd is a way to cope-
up with its goal in providing the quality education you deserved.
It is easy, user friendly, and interactive. It allows you to give comments
or answers to their parts freely. Icons with labels are provided as your guide
throughout. Words, figures, and tables are made simple for your easy
understanding.
This Module will help you learn Science facts and concepts and develop
your positive attitude, values, and interest in Science.
Explore this Module thoroughly for the best experience. Have fun!

How to learn from this module:

To be guided in using this module, you may do the following:
1. Read and follow the directions and or instructions in the activities and
exercises carefully and diligently.
2. Take your time to read the lessons.
3. Answer all given tests, activities, and exercises honestly.
4. Check your answers in the key answers provided in the last few pages of
the module.
5. Familiarize yourself with the following Icons and Terms:
Let Us Learn! - It has the objectives of the module.

Let Us Try! - Pretest or Preassessment.

Let Us Study - Introduction of a new lesson or the lesson itself.

Let Us Practice – Activities for practicing the concepts.

Let Us Practice More – Additional activities for practicing the concepts.

Let Us Remember – Additional activities for practicing the concepts.

Let Us Assess – Posttest or Post assessment.

Let Us Enhance - Enrichment activities.

Let Us Reflect - Application of the concept to a real-life situation.

Answer key to Activities – Key answers to the activities, exercises, and tests.
References - Useful links for the resources used in this module

ii
 Let Us Learn!

Hello! Good day!

We have some questions here!

Have you ever wondered how our whole body works simultaneously?

Just like when you run fast, you breathe fast too, and your heart beats
fast as well. Have you ever been to a place with less or no ventilation?
Certainly, a choking environment will come into your mind as modern science
proves the concept that almost all life forms on Earth require oxygen to live.

Our respiratory and circulatory systems enable us to sustain life by

facilitating oxygen intake and usage within the body.

In this module we will go along with these questions by exploring the

following competencies:

1. Explain how the respiratory and circulatory systems work together to

transport nutrients, gases, and other molecules to and from the different parts
of the body. (S9LT-la-b-26); and

2. Infer how one’s lifestyle can affect the functioning of respiratory and
circulatory systems. (S9LT-lc-27)

1
 Let Us Try!

Are you ready? Yes, certainly you are!

How well do you know about the respiratory and circulatory systems?

Let us try to find out by answering the following questions. After

honestly answering this, you may check the answers in the last part of this
module.

Multiple Choice
Identify and choose the best answer that completes the statement or the
question. Write the letter of your answer on a separate sheet of paper.

1. Which of the following organ responsible for the pumping of blood and other
materials throughout the body
a. Circulatory system b. Respiratory system c. Lungs d. Heart

2. Which of the following statements is NOT TRUE about the nasal cavity?
a. It warms and humidifies the air reaching the lungs.
b. It contains an abundant blood supply
c. It contains tiny hairs for trapping dust and other foreign materials.
d. All of the above

3. Which of the following arteries does not contain oxygen-rich blood?

a. Aorta b. Renal arteries c. Coronary arteries d. Pulmonary arteries

4. Where do gases exchange in the body occur?

a. Trachea b. Alveoli c. Primary bronchi d. Terminal bronchi

5. A long term smoking habit can destroy the cilia along the lining of the air
passages. How might this affect a smoker’s health?
a. The smoker will have a very limited air.
b. The smoker will have difficulty in breathing.
c. The smoker will not be able to filter pollutants.
d. The smoker’s respiratory tract will be blocked

6. When the ventricles contract, the__________________

a. bicuspid valve opens and the tricuspid valve closes.
b. tricuspid valve opens and the bicuspid valve closes.
c. bicuspid and tricuspid valve opens.
d. bicuspid and tricuspid valve closes.

2
7. In which blood vessel does the exchange of nutrients and wastes happen?
a. arteries b. arterioles c. capillaries d. venules

8. The entrance and exit of air in the human body is accomplished by a

mechanical process called _________.
a. breathing b. ventilation c. excretion d. elimination

9. When you inhale, your lungs ___________.

a. inflates b. deflates c. remove gas d. inflate, then deflate

10. Which of the following is the correct path of blood flow?

a. Left ventricle, aorta, pulmonary artery
b. Pulmonary artery, left atrium, left ventricle
c. Pulmonary vein, pulmonary artery, right atrium
d. Pulmonary artery, pulmonary capillaries, pulmonary vein, left atrium

11. What is the most significant compound in gaseous transport?

a. Hemoglobin b. Adrenaline c. Acetylcholine d. Antihistamine

12. Which of the following statement is NOT TRUE?

a. Oxygen is taken up in the body during inhalation.
b. The heart is divided into 4 chambers.
c. Oxygen is delivered to the tissue by the respiratory system.
d. Alveoli are tiny sacs at the end of bronchioles.

13. A patient experiences the symptoms of sudden numbness and weakness

in the arm, stiffness of the half part of the body, leg and face, slurred speech,
and difficulty in balance. Which of the following diseases is experiencing by
the patient?
a. Asthma b. Tuberculosis c. Stroke d. Hypertension

14. Which of the following activities help to strengthen the cardiovascular

system?
a. Sleeping b. Swimming c. drinking plenty of water d. Planting

15. Arteries have the thickest walls among the blood vessels because ______
a. they are the strongest blood vessel.
b. there are more muscles around them.
c. they receive tremendous pressure while blood passes through them.
d. they are embedded in the muscles.

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 Let Us Study

Way to go! Let us level up!

Observe and compare these two pictures. Which one consumes more
oxygen?

Illustrated by: Queeny F. Coronel

Have you experienced the feeling as if your lungs would burst out of
your chest just to supply your body enough air? In what instances? Certainly,
you feel this after doing an activity that uses a lot of body energy. As we use
energy, our demand for oxygen increases. Normally, the air takes into the
body through the process of breathing. The air that enters the body includes
dust, trace gases, and oxygen. Blood absorbs oxygen in exchange for carbon
dioxide, which is the product of energy production in cells and is released
during exhalation. During an activity, the body breaks down its food source
to produce energy. However, oxygen is required to convert food into energy.
Energy production utilizes oxygen and releases carbon dioxide as a product.
As the body loses supply of oxygen during activity, the person tries to gasp for
air to have enough oxygen in the body.

Rank the following activities according to the degree they require you to
consume oxygen, 5 being the highest and 1 being the lowest. Assume that
each activity is done for 10 minutes.

__ sleeping
__ climbing of trees
__ walking to church
__ playing video games
__ singing

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Human Respiratory System

Respiration is the process of taking in oxygen from the environment and

delivering it to the cells. At the same time, carbon dioxide is removed and
taken out of the body. The human respiratory system, therefore, is responsible
for the exchange of gases between humans and the environment.
This system, which is generally comprised of nose, pharynx, larynx,
trachea, and the lungs, also allows for the filtration, humidification, and
warming of the air when it enters the nostrils and the air passages. This role
of the system minimizes the harmful content of the air reaching the lungs
before the gas exchange takes place in the body.

Human Circulatory System

Alone, can respiratory organs supply every cell in our body with oxygen?
As the respiratory system initiates gas exchanges within the body, another
system supplies our cells with oxygen, the circulatory system.

The rhythmic contraction and relaxation of the heart are what produce
the sound all known as “heartbeat”. The pumping action of the heart and the
network of channels are responsible for carrying and distributing nutrients,
gases, hormones, antibodies, and many other important substances that the
body needs to live. The heart works throughout our lives and never stops to
rest. This system is divided into three major parts: the heart, the blood
vessels, and the blood.

Can you imagine what will happen when the heart rests?

What’s your lifestyle?

How many people do exercise every day? How many people eat healthy
food instead of buying fast foods or instant foods? Are they aware of the
lifestyle that they have?

The risk of people acquiring respiratory and heart diseases is increasing

nowadays, especially that the world is facing a crisis due to the Covid-19
pandemic.

If a person lives with an unhealthy lifestyle such as smoking, an

unbalanced diet, and sleeping too late, what will happen to the body?

Physical and mental changes occur usually if a person lives with an

unhealthy lifestyle and leads with several diseases particularly respiratory
and cardiovascular disease. These diseases claim the lives of people. Living a
healthy lifestyle can prevent the onset of cardiovascular disease.

5
 Let Us Practice

Great! You made it this far! Let us continue learning!

After honestly answering this. You may check your answer in the
Answer Key Section.

Activity 1. The Breathing Mechanism

Objectives:
a. Explore inhalation and exhalation process
b. Explain the process of breathing
c. Illustrate the changes of the physical body during the breathing process

Materials:
• Activity sheet
• Human body

Procedure:
1. Find someone who can be your partner for the activity.
2. Stand facing each other so that you will be able to observe each other.
3. Both of you execute deep inhalation or taking in of air and observe your
partner’s body as well as you observe yours.
4. Now do the exhalation process or taking out of the air and observe.
5. Draw your observations inside the boxes. You may include specific
figures like arrows.
INHALATION EXHALATION

Guide Questions:
1. How will you describe the physical changes of the body during
breathing?
2. Why do you think the chest expands and relaxes during breathing?
3. Is it possible to breathe without these changes or body motions? Why?

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 Activity 2: The Lungs
Objectives:
a. Describe the key parts of the lungs
b. Label the parts of the lungs

Materials:
• Diagram or picture
• Activity sheet

Procedure:
1. Read and analyze the paragraph below.
2. From the given picture identify and label the key parts of the lungs.

Key concept
The lung is the vital organ responsible for breathing particularly gas
exchange. The human body has 1 pair of lungs. Each lung has 2 lobes that
have its pleura-sac. Here are its important parts to work well: the main stem
is the trachea, the large branching stems are the bronchi, and all the little
stems are the bronchioles. The little grapes like are air sacs or alveoli (alveolus
in singular).

a.

c.
b.

d.

Figure 1. Lungs (2020. Upload.Wikimedia.Org. accessed July 13, 2020,

https://upload.wikimedia.org/wikipedia/commons/9/9b/the lungs_clip_art

Guide Questions:
1. What device can you compare to the human lungs? How does it work?
2. How will you describe the feature of the lungs?
3. Would it be possible to work if only one lung is functioning?

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 Activity 3: The flow of the air to the body
Objectives:
a. Describe the functions of each part of the breathing system
b. Explain the flow of the air throughout the body
c. Trace the flow of air to the body
Procedure:
1. After reading and understanding the concept below, illustrate the parts
of the breathing system fitting the diagram below.
2. Trace the flow of the air by illustrating, labeling, and putting arrows on
its parts.
Key concept:
The air we breathe goes through the nose or the nasal opening towards
the nasal cavity, these parts are lined with mucus membrane and cilia or tiny
hairs to filter particles in the air. The pharynx is also known as the throat. It
contains the epiglottis which closes off the opening of the trachea when you
swallow. Right below the epiglottis is the larynx or the voice box. Trachea,
which is also known as the windpipe. It is made up of muscle, elastic fibers,
and rings of cartilage. The trachea is lined with mucus-secreting cells and
cilia to trap foreign materials, from this tube, air moves towards the bronchi
(bronchus for singular), it is the extension of the trachea that divides to the
left and right lungs. Its further branches to for bronchioles or smaller
branches that carry in air or out from the alveoli. Alveoli then are tiny sacs
inside the lungs where gas exchange happens. They are one-cell thick and are
lined with capillary beds. The alveoli increase the surface area for a more
efficient exchange of gases in the lungs.

Figure 2.
Illustrated by: Queeny F. Coronel

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Guide Questions:
1. How will you describe the pathway of the oxygen in the breathing
system?
2. What will happen if one part of the system fails to carry out its
function properly?

Activity 4: The Human Heart

Objectives:
a. Describe the parts of the heart
b. Explain the functions of each part of the heart

Materials:
• activity sheet
• coloring materials
• pen

Procedure:
1. Study the following terms and functions below.
2. Label the parts of the heart base on the information given.
3. Color the key parts of the heart.

Key concept
The chambers
o Two atria – Receiving chambers of the heart. These receive blood
through veins.
a. Right Atrium- It accepts blood from the body.
b. Left Atrium - It accepts blood from the lungs.
o Two ventricles- Pumping chambers of the heart. These forces the blood
out into the arteries.
c. Right Ventricle- It pumps blood towards the lungs.
d. Left Ventricle- It pumps blood towards the body.
The valves- It prevents blood from back flowing.
e. Tricuspid valve- between the right atrium and right ventricle
f. Bicuspid valve- between the left atrium and left ventricle
g. Pulmonary valve- at the base of the pulmonary artery
h. Aortic valve- at the base of the aorta

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The Vena cava- The largest vein. It carries blood towards the heart.
i. Superior vena cava- conveys blood from the upper extremities
towards the heart
j. Inferior vena cava- conveys blood from the lower extremities towards
the heart
Other parts
k. Septum- It divides the right and left chambers.
l. Aorta- The largest artery. It conveys blood from the heart to different
parts of the body.
m. Pulmonary artery- It conveys oxygen-poor blood from the heart to
the lungs.
n. Pulmonary vein- It conveys oxygen-rich blood from the lungs to the
heart.

i l
. . m
.
g. c
a. ..

f.
e.

d.
b.

k
j .
.

Figure 3. Parts of the heart ( The heart, n.d., 2020. Flickr. com/creativecommons accessed July 12, 2020,
https://www.flickr.com/photos/37961306@N05/4074989459/.

10
 Activity 5: The flow of blood
Objectives:
a. Describe the flow of the blood and gas exchange within the heart,
circulatory system, and lungs.
b. Explain the mechanism of how the respiratory and circulatory systems
work together.
c. Trace the flow of the different types of blood into the heart and to
different parts of the body.
Materials.
• Activity sheet
• Colored pens or any coloring materials (red and blue)
Procedure:
1. Read and analyze the concept below.
2. Using the diagram below, trace the path flow of the blood using coloring
materials.
3. Use red color for oxygenated blood (oxygen-rich blood) and use blue
color for deoxygenated blood (oxygen-poor blood).

Key concept:
There are two types of blood that circulates in the whole body. The
oxygen-rich blood or the oxygenated blood and the oxygen-poor blood or the
deoxygenated blood. Deoxygenated blood from the body will start its journey
at the vena cava (superior and inferior vena cava) and will enter the first heart
chamber, the right atrium, the blood will be pumped down to the right
ventricle passing through the tricuspid valve. The right ventricle will pump
the blood out of the heart to the lungs passing through the pulmonary artery.
Before the blood enters the pulmonary artery, it is first prevented by the
semilunar valve from backflowing. From the pulmonary artery, blood enters
the capillaries in the lungs for gas exchange which happens inside the alveoli.
During the gas exchange wherein the carbon dioxide carried by the blood will
be replaced by oxygen, then now this blood will be called as oxygenated blood.
Oxygenated blood from the lungs will go back to the heart passing through
the pulmonary vein. The blood takes into the left atrium and will be pumped
down to the left ventricle passing through the bicuspid valve. The left ventricle
will pump the blood out of the heart passing through the aortic valve and then
to the aorta. Oxygenated blood will be now distributed throughout the
different parts of the body.

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 PULMONARY
CIRCULATION

SYSTEMIC
CIRCULATION

Figure 5. The pathway of the blood

Illustrated by: Queeny F. Coronel

Guide Questions:
1. Base on the diagram, how will you describe pulmonary circulation and
systemic circulation?

2. How will you compare the pathway of deoxygenated blood from the
oxygenated blood?

3. How does circulatory and respiratory work together?

4. Make a simple summary of the pathway of the blood using a flow chart.

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 Let Us Practice More

Activity 6: Effects of Electronic Cigarette or Vape into the body

Direction: Read and understand the text below. You can use a separate sheet
of paper on answering the following questions.
Cigarette use is the leading cause of preventable death and is estimated to
kill more than 5 million persons each year nationwide. And as years go by,
the age of cigarette users became younger. Cigarette use and exposure to
second-hand smoke pose a major public health problem in the Philippines. In
today’s generation, electric cigarettes or “vape” became popular as people were
searching for an alternative to cigarette (tobacco) that has become known to
harm nearly every organ of the body and has caused many diseases.
What is an electric cigarette and what is its effect on the body? Does
vaping is as bad as smoking?

E-cigarettes or vapes are smokable, refillable or replaceable cartridges

or containers that hold liquid that contains nicotine, solvents, and chemical
flavors. When a person inhales ("vaping"), they are putting negative pressure
on the device that triggers a battery to heat the liquid solution, which is
then atomized into an inhalable vapor.

September of 2019, saw a rash of nearly 500 cases of respiratory illness

linked to vaping throughout the US, according to the CDC, which reports
symptoms to include cough, chest pain, nausea, shortness of breath,
vomiting, or diarrhea. The exact component of vape fluid had not been
identified as of that time, but illness seems to affect users of both nicotine
and cannabis e-cigarettes.
Nicotine is very addictive, and that seems to be a cause for concern. Low
doses may cause nausea, vomiting, abdominal pain, and eye irritation. High
doses of nicotine may cause tachycardia, high blood pressure, seizures, coma,
and death.
Moreover, researchers found that 92% of e-cigarettes studied had at least
one of three different compounds known to cause popcorn lung. “Popcorn
lung” (bronchiolitis obliterans) is a lung disease that results in damaging and
tightening of the airways in the lungs.
Questions:
1. What does vaping do to the body?

2. Why does vaping become popular especially to young ones?

13
 Activity 7: The impact of the Novel Coronavirus or Covid-19
Direction: Read and understand the text below. You can use a separate sheet
of paper on answering the following questions.
Coronavirus disease 2019 (COVID-19)
It is defined as an illness caused by a novel coronavirus now called
severe as acute respiratory syndrome coronavirus 2 (SARS-CoV-2; formerly
called 2019-nCoV). On March 11, 2020, WHO declared COVID-19 a global
pandemic.
Common signs and symptoms can include fever, cough, tiredness,
shortness of breath or difficulty of breathing, muscle aches, chills, sore throat,
loss of taste or smell, headache, chest pain. This list is not all-inclusive. Other
less common symptoms have been reported, such as nausea, vomiting, and
diarrhea. Children have similar symptoms to adults and generally have mild
illness.
Aside from the threats by the Covid-19, a broad impact of the pandemic
is felt, from dropping off the economy, healthcare, and social problems,
people’s lifestyle is also interrupted. Our circadian rhythm or our schedule of
sleeping, eating, taking of baths is somehow changed. Our feelings and moods
are affected. Even a simple wearing of the mask has several issues, though it
is one of the main preventive measures to control the spread of virus a long
period of wearing of this may cause to limit the breathing process wherein
lack of oxygen in the body makes you feel difficult to breathe, dizzy and many
more. These things might also affect the functionality of our body system.
Questions:
1. How did the pandemic change your lifestyle?
_____________________________________________________________________
_____________________________________________________________________
2. Give at least three considerable impacts of the pandemic to one’s
lifestyle.
_____________________________________________________________________
_____________________________________________________________________
3. Make a simple routine plan on maintaining a healthy lifestyle.

My Routine Plan

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 Let Us Remember
Splendid! Now, let us gather what we have learned.

I Learned.
Complete the organizational chart below. Use separate sheet of paper
for your answer.

Organ System

Circulatory
Main parts System

Nasal cavity Blood vessels

Responsible
for gas
exchange types
between
human and
environmen
t

lungs

blood function

heart function

parts arranged
according to
blood flow

Superior & inferior

vena cava Tricuspid valve

Pulmonary valve

Left atrium lungs

aorta

15
 Let Us Assess

Very Good! We are almost there! It is time to try the fruit of our journey!

Multiple Choice
Identify and choose the best answer that completes the statement or the
question. Write the letter of your answer on a separate sheet of paper.

1. Which of the following statement is NOT TRUE?

a. Alveoli are tiny sacs at the end of bronchioles.
b. The heart is divided into 4 chambers.
c. Oxygen is delivered to the tissue by respiratory system.
d. Oxygen is taken up in the body during inhalation.

2. Which of the following sequence is correct?

a. nasal cavity → trachea → pharynx → larynx→ bronchi → alveoli
b. nasal cavity → trachea → larynx → pharynx → bronchi → alveoli
c. nasal cavity → pharynx→ larynx → trachea → bronchi→ alveoli
d. nasal cavity → pharynx → trachea → larynx → bronchi → alveoli

3. What kind of blood enters vena cava?

a. Oxygen-rich blood c. Both a and b
b. Oxygen-poor blood d. Neither a nor b

4. Which of the following activities help to strengthen the cardiovascular

system?
a. Sleeping b. Swimming d. Drinking plenty of water d. Planting

5. What happens when the ventricles contract?

a. Bicuspid valve opens and the tricuspid valve closes.
b. Tricuspid valve opens and the bicuspid valve closes.
c. Bicuspid and tricuspid valve opens.
d. Bicuspid and tricuspid valve closes.

6. Which of the following organ system responsible for exchanging of

oxygen and carbon dioxide?
a. Circulatory system b. Respiratory system c. Lungs d. Heart

7. Which structure moves up and down to alter the volume of the chest
cavity?
a. Diaphragm b. Epiglottis c. Larynx d. Trachea

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8. The oxygen-rich blood supply to the lungs is provided by the ________.
a. pulmonary artery b. aorta c. coronary artery d. vena cava

9. Which of the following chambers of heart carries deoxygenated blood?

a. right atrium and right ventricle
b. left atrium and left ventricle
c. right and left ventricles
d. right and left atria

10. What blood vessel exerts the lowest pressure?

a. arteries b. capillaries c. arterioles d.venules

11. What happens to your lungs when you inhale?

a. inflates b. deflates c. remove gas d. inflate, then deflate

12. A patient experiences the symptoms of sudden numbness and

weakness in the arm, stiffness of the half part of the body, leg and face,
slurred speech, and difficulty in balance. Which of the following diseases
is experiencing by the patient?
a. Asthma b. Tuberculosis c. Stroke d. Hypertension

13. The blood from the superior vena cava enters the heart by way of
the__________.
a. left atrium b. right atrium c. left ventricle d. right ventricle

14. What part of the heart prevents blood from backflowing?

a. ventricles b. atria c. valve d. vena cava

15. The entrance and exit of air in the human body is accomplished by a
mechanical process called _________.
a. breathing b. ventilation c. excretion d. elimination

17
 Let Us Enhance

Absolutely incredible! A little bit more!

Search words as many as you can. List down all the words that you can
find. Create a sentence using the words that you can find if it is related to the
lesson.

Let Us Reflect

Congratulations! You made it! Might you want to share your thoughts
and what you have learned from the lesson?

Respiratory and Circulatory System

Why is it among the organ systems, the respiratory and circulatory

system is the most affected or has the most common acquired diseases?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________

18
 19
Let Us Practice! Activity 2.
a. trachea
Let Us Practice! Activity 1. b. bronchi
1. During inhalation; the chest c. bronchioles
expands as the diaphragm and
intercoastal muscles contract. While d. alveoli
during exhalation; the intercoastal
muscles relax bringing the chest back 1. A lung mechanical ventilator. The
to its position and the diaphragm also machine works by bringing oxygen to
relaxes. the lungs and taking carbon dioxide
out of the lungs. This allows a patient
2. As air takes in to the body, the who has trouble breathing to receive
volume of the lungs expands and as the proper amount of oxygen.
we breathe out air lungs relaxes.
2. (Answer may vary) It is a soft organ
3. No containing connected tubes with
different sizes that provides pathway
for the air and for gas exchange.
Let Us Practice! Activity 3. 3. Yes, since each lung contain
separated lobes that has its own
1. (Answer may vary) It is a branching
pleura sac, but it would be difficult for
pathway starts with the nose until it
a single working lung to process gas
enters the lungs and reaches the
exchange for a proper breathing.
alveoli. Similarly, carbon dioxide
passes from the blood into the alveoli
and is then exhaled.
2. (Answer may vary) There will be a
difficulty of breathing or failure of
breathing process if one of the parts
will not work.
Let Us Assess! Let Us Study!
1 Let Us Try!
1. C 6. C 11. A
2. C 7. B 12. C 4 1. D 6. C 11. A
3. B 8. A 13. B 5 2. B 7. C 12. C
4. B 9. A 14. C 2 3. D 8. A 13. C
5. C 10. D 15. A 3 4. B 9. A 14. B
5. C 10. B 15. C
Answer key to Activities
 20
Let Us Practice More! Activity7.
1. (Answer may vary)
2. (Answer may vary) Change of
habits, feeling and emotion.
Let Us Practice! Activity 5.
1. Pulmonary circulation is the
Let Us Practice More! Activity6.
portion of the circulatory system
which carries deoxygenated blood 1. (Answer may vary) It damages the
away from the right ventricle, to the lungs. It tightens the air pathways
lungs, and returns oxygenated blood and may complicate to other severe
to the left atrium and ventricle of the illnesses.
heart. While systemic
circulation carries oxygenated blood 2. (Answer may vary) Young people
from the left ventricle, through the look for an alternative to cigarette
arteries, to the capillaries in the (tobacco). Most of them see it as one of
tissues of the body. It provides the new trend and it contain addictive
functional blood supply to all body substances.
tissue and picks up CO2.
2. Oxygenated blood then leaves from
the lungs to left atrium passing
pulmonary vein, then down to the left
ventricles passing bicuspid valve,
pumped out of the heart passing
aortic valve and aorta then to the Let Us Practice! Activity 4.
different parts of the body.
a. right atrium
Deoxygenated blood from the different
parts of the body enters right atrium b. right ventricle
passing vena cava, then down to right
ventricle passing tricuspid valve, c. left atrium
blood pumped out of the heart going
to the lungs passing pulmonary valve d. left ventricle
and pulmonary arteries. e. tricuspid valve
3. They work together as Respiratory f. bicuspid valve
provides oxygen to the body and
circulatory transport this oxygen g. pulmonary valve
together with other nutrients to the
body. i. superior vena cava
j. inferior vena cava
k. septum
l. aorta
m. pulmonary artery
 20
Let Us Remember!
 References

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atomy-and-physiology-the-relationships-of-the-respiratory-
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