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

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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. Coronel
Management Team: Dr. Josephine L. Fadul - SDS
Dr. Honey Lynne A. Boyles – EPS in Science
Lorna C. Ragos – LRMDS Supervisor
Jecson L. Oafallas – Project Development Officer II
Jeffrey E. Santiago- Librarian 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 deserve.
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.

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 in a separate sheet of paper.

1. Which organ is 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 contains an abundant blood supply
b. It warms and humidifies the air reaching the lungs.
c. It contains tiny hairs for trapping dust and other foreign materials.
d. It a large, air-filled space above and behind the nose in the middle of the
face.

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

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?

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. Moreover, the
rhythmic contraction and relaxation of the heart produce the sound of
“heartbeat” - the pumping action of the heart.

Together, 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.

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 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. Perform 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. Inside the boxes, draw the physical body changes you have observed
with your partner. You may include specific figures like arrows.

INHALATION EXHALATION

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Guide Questions:

1. Breathing is the process of inhaling and exhaling. How will you describe
the physical changes of the body when you breathe?
2. Why do you think the chest expands then relaxes during breathing?
3. Is it possible to breathe without these changes or movements in the
body? Why?

Activity 2: The Lungs

Objectives:
a. Describe the key parts of the lungs
b. Label the parts of the lungs

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 own pleura-sac. Here are its important parts to work well: the main
stem is the (a) trachea, the large branching stems are the (b) bronchi, and all
the little stems are the (c) bronchioles. The little grapes like are air sacs or
(d)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. Draw the parts of the respiratory system

b. Label the parts of the respiratory system
c. Explain the flow of the air throughout the body
d. Trace the flow of air in the body
Procedure:

1. After reading and understanding the concept below, draw the parts of
the breathing system fitting the diagram below. Label each part
2. Trace the flow of the air by 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 is made up of muscle,
elastic fibers, and rings of cartilage and is lined with mucus-secreting cells
and cilia to trap foreign materials. from this tube, air moves towards the
bronchi (bronchus for singular), which serve as the extension of the trachea
that divides to the left and right lungs. The bronchi further stem out into tiny
stems called bronchioles that carry the air in 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.

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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 – these are the 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- These chambers force 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- these prevent the backward flow of the blood.

e. Tricuspid valve- found between the right atrium and right ventricle
f. Bicuspid valve- found between the left atrium and left ventricle
g. Pulmonary valve- found 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.

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/.

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.

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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

Guide Questions:

1. Based 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? Is vaping
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 Disease or Covid-19
Direction: Read and understand the text below. You can use a separate sheet
of paper in answering the following questions.

Coronavirus Disease 2019 (COVID-19)

Coronavirus Disease 2019 (COVID-19) is an illness caused by a novel
coronavirus now called severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2; formerly called 2019-nCoV).

On March 11, 2020, WHO declared COVID-19 as 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.

In addition, our circadian rhythm or our schedule of sleeping, eating,

taking of bath 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.

14
 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.

Let Us Assess
Very Good! We are almost there! It is time to try the fruit of our journey!
Choose the best answer that completes the statement or the question.
Write the letter of your answer in 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.

15
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 b. Oxygen-poor blood c. Both a&b d. Neither a nor b

4. Which activity helps 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 organ system is for exchanging oxygen and carbon dioxide?

a. Circulatory system b. Respiratory system c. Lungs d. Heart

7. Which structure moves up and down to alter volume of the chest

cavity?
a. Diaphragm b. Epiglottis c. Larynx d. Trachea

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 c. right and left ventricles
b. left atrium and left ventricle d. right and left atria
10. What blood vessel exerts the lowest pressure?
a. arteries b. capillaries c. arterioles d. ventricles

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 disease has 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

16
 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 as a mechanical process.
a. breathing b. ventilation c. excretion d. elimination

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?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________

17
 18
Let Us Practice! Activity 4. Let Us Practice! Activity 3.
a. right atrium 1. (Answer may vary) It is a
b. tricuspid valve branching pathway starts with the
c. left atrium nose until it enters the lungs and
d. left ventricle reaches the alveoli. Similarly,
e. aorta carbon dioxide passes from the
f. superior vena cava blood into the alveoli and is then
g. pulmonary artery 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 Practice! Activity 2.
a. trachea
b. bronchi
c. bronchioles
d. alveoli
1. A lung mechanical ventilator.
The machine works by bringing
oxygen to the lungs and taking
carbon dioxide out of the lungs. Let Us Practice! Activity 1.
This allows a patient who has 1. During inhalation; the chest
trouble breathing to receive the expands as the diaphragm and
proper amount of oxygen. intercoastal muscles contract.
2. (Answer may vary) It is a soft While during exhalation; the
organ containing connected tubes intercoastal muscles relax bringing
with different sizes that provides the chest back to its position and
pathway for the air and for gas the diaphragm also relaxes.
exchange. 2. As air takes in to the body, the
3. Yes, since each lung contain volume of the lungs expands and
separated lobes that has its own as we breathe out air lungs relaxes.
pleura sac, but it would be difficult 3. No
for a single working lung to process
gas exchange for a proper
breathing.
Let Us Assess! Let Us Study! Let Us Try!
1. C 6. C 11. A 1 1. D 6. C 11. A
2. C 7. B 12. C 4 2. A 7. C 12. D
3. B 8. A 13. B 5 3. D 8. A 13. C
4. B 9. A 14. C 2 4. B 9. A 14. B
5. C 10. D 15. A 3 5. C 10. B 15. C
Answer key to Activities
 19
Let Us Practice More! Activity7. Let Us Practice! Activity 5.
1. (Answer may vary) 1. Pulmonary circulation is the
2. (Answer may vary) Change of portion of the circulatory system
habits, feeling and emotion. which carries deoxygenated blood
3. (Answer may vary) away from the right ventricle, to the
lungs, and returns oxygenated
blood to the left atrium and
ventricle of the heart. While
systemic circulation carries
oxygenated blood from the left
ventricle, through the arteries, to
the capillaries in the tissues of the
body. It provides the functional
blood supply to all body 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
Let Us Practice More! Activity6. bicuspid valve, pumped out of the
1. (Answer may vary) It damages heart passing aortic valve and
the lungs. It tightens the air aorta then to the different parts of
pathways and may complicate to the body. Deoxygenated blood from
other severe illnesses. the different parts of the body
2. (Answer may vary) Young people enters right atrium passing vena
look for an alternative to cigarette cava, then down to right ventricle
(tobacco). Most of them see it as passing tricuspid valve, blood
one of new trend and it contain pumped out of the heart going to
addictive substances. the lungs passing pulmonary valve
3. 1. (Answer may vary) and pulmonary arteries.
3. They work together as
Respiratory provides oxygen to the
body and circulatory transport this
oxygen together with other
nutrients to the body.
21
 References

Resurreccion, Lyn. 2020. "70 Percent Of Filipinos Favor Vaping | Lyn

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For inquiries or feedback, please write or call:

Department of Education – Region XI

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Email Address: http://deped.tagumcity.gov.ph

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