SCIENCE 5 SSES
Quarter 1 – Module 6:
The Circulatory System
(How Blood Flows, Diseases and
Healthy Habits)
What I Need to Know
After going through this module, you will understand how blood flows from
the heart to the rest of the body, the common ailments of the circulatory system
and the healthy habits you could do to maintain it.
What I Know
Identify what is/are asked. Write your answers on a separate sheet of
paper.
_______________1. It is the transport system of the body.
_______________2. It is the liquid part that is constantly flowing throughout
the body.
_______________3. These are the smallest of formed components of blood
that help in blood clotting.
_______________4. It is the movement of deoxygenated blood from the heart
and into the lungs.
_______________5. It is the pumping organ of the body.
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Lesson 1 How Blood Flows (Blood Circulation)
In
mammals,
the
circulation occurs in two circuits,
and blood is circulated through
the heart for two times. This type
of circulation is called the double
circulation.
Pulmonary and systematic
circulation are the two types of
circulations that occur in a double
circulation system.
The difference between
pulmonary
and
systemic
circulation stems from the nature
of the blood and the destination
of the blood. The main difference between pulmonary and systematic circulation is that
Figure 1: Diagram of the Pulmonary and Systemic Circuits
pulmonary
circulation
carries
deoxygenated blood from heart to
lungs and oxygenated blood back to the heart whereas systemic circulation carries
oxygenated blood from the heart throughout the body and deoxygenated blood back to
the heart.
What is Pulmonary Circulation
Pulmonary circulation is the circulation system that carries deoxygenated blood
to the lungs and returns oxygenated blood from the lungs back to the heart. The two
blood vessels involved in the pulmonary circulation are pulmonary artery and the
pulmonary vein. The deoxygenated blood flows into the right ventricle from the right
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atrium. This blood is carried to the alveoli of lungs for the oxygenation by the pulmonary
artery. The pulmonary artery, which immediately originates from the right ventricle, is
called the pulmonary trunk. The pulmonary trunk divides into two; the left pulmonary
artery and the right pulmonary artery. The left pulmonary artery carries blood to the
left lung while the right pulmonary artery carries blood to the right lung.
Figure 2: Pulmonary Circulation
Carbon dioxide is removed from the blood while oxygen is taken into the blood at
the alveolar capillaries. The oxygenated blood is carried to the left atrium of the heart
by four pulmonary veins. A small amount of oxygenated blood is carried to the heart by
the bronchial veins.
What is Systemic Circulation
The systemic circulation is the circulation system that carries oxygenated blood
throughout the body and returns the deoxygenated blood to the heart from the body
tissues. The oxygenated blood from the lungs returns to the left atrium of the heart
through pulmonary veins. This blood flows into the left ventricle and comes out from the
heart through the aorta. The aorta branches into small arteries, which carry blood to
different organs in the body. Within an organ or tissue, these arteries branch to
arterioles, which make blood capillaries. The exchange of oxygen and nutrients with the
metabolizing cells occurs via blood capillaries.
Carbon dioxide and other metabolic wastes are transported back to the blood.
The deoxygenated blood drains back to the venules and returns to the right atrium of
the heart by vena cava. The deoxygenated blood from the upper half of the body above
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the diaphragm drains by the superior vena cava while the deoxygenated blood from the
lower half of the body drains by the inferior vena cava.
Figure 3: Difference Between the Pulmonary and Systemic Circulation
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Study the flow chart below of how blood circulates through the heart:
Figure 4: Circulation of Blood Through the Heart
Lesson 2
Common Ailments of the Circulatory System
The circulatory system is your heart and blood vessels, and it’s essential to
keeping your body functioning. This finely tuned system carries oxygen, nutrients,
electrolytes, and hormones throughout your body. Interruptions, blockage, or diseases
that affect how your heart or blood vessels pump blood can cause complications such as
heart disease or stroke.
These complications can arise due to a variety of factors, from genetics to
lifestyle. Read on to learn more about the types circulatory system diseases and
disorders and what their symptoms are.
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•
High blood pressure
Blood pressure is the measurement of how much force is used to pump
blood through your arteries. If you have high blood pressure, also called
hypertension, it means the force is higher than it should be. High blood pressure
can damage your heart and lead to heart disease, stroke, or kidney disease.
There are no symptoms with high blood pressure, which is why it’s often
called “the silent killer.”
•
Atherosclerosis and coronary artery disease
Atherosclerosis, also known as hardening of the arteries, occurs when
plaque builds up on the walls of your arteries and eventually blocks blood flow.
Plaque is made of cholesterol, fat, and calcium.
Coronary artery disease indicates that the plaque buildup in your arteries
has caused the arteries to narrow and harden. Blood clots can further block the
arteries.
Coronary artery disease develops over time. You can have it but not be
aware of any symptoms. Other times, it may cause chest pain or the sensation of
heaviness in the chest.
•
Heart attacks
A heart attack occurs when not enough blood reaches your heart. This can
happen due to artery blockage. Heart attacks damage the heart muscle and are
medical emergencies.
Call 911 or have someone else call if you have symptoms such as:
-
pain in the center or left side of the chest that feels like mild or severe
discomfort, pressure, fullness, or squeezing
-
pain that radiates from the jaw, shoulder, arm, or across the back
-
shortness of breath
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•
-
sweating
-
nausea
-
irregular heartbeat
-
unconsciousness
Heart failure
Sometimes called congestive heart failure, heart failure occurs when the
heart muscle is weakened or damaged. It can no longer pump the volume of blood
needed through the body. Heart failure normally occurs when you’ve had other heart
problems, such as a heart attack or coronary artery disease.
Early symptoms of heart failure include fatigue, swelling in your ankles, and
increased need to urinate at night. More severe symptoms include rapid breathing,
chest pain, and fainting.
•
Strokes
Strokes often occur when a blood clot blocks an artery in the brain and
reduces the blood supply. They also can happen when a blood vessel in the brain breaks
open. Both events keep blood and oxygen from reaching the brain. As a result, parts
of the brain are likely to be damaged.
•
Abdominal aortic aneurisms
An abdominal aortic aneurism is a bulge in a weakened part of the aorta. The
aorta is the largest blood vessel in your body. It carries blood from your heart to
your abdomen, legs, and pelvis. If the aorta ruptures, it can cause heavy bleeding
that’s life-threatening.
•
Peripheral artery disease
Peripheral artery disease (PAD) is atherosclerosis that occurs in the
extremities, usually in your legs. It reduces blood flow to your legs, as well as to your
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heart and brain. If you have PAD, you’re at greater risk of developing other
circulatory system diseases.
What increases your risk of circulatory system diseases?
Certain factors can increase your risk for circulatory system diseases.
➢ Modifiable risk factors are factors that can be controlled, changed, or treated
with lifestyle changes. These risk factors include:
o
lack of exercise
o
being overweight
o
smoking
o
overuse of alcohol
o
high levels of stress
o
poor diet
o
Managing certain conditions such as high blood pressure and diabetes can
also affect your risk.
➢ Nonmodifiable risk factors are risk factors that can’t be controlled, treated, or
modified include:
o
advanced age
o
maleness
o
family history of heart disease, stroke, high blood pressure, or high
cholesterol
o
certain ethnicities
Lesson 3
Healthy Habits to Keep the Heart, Blood, and Blood vessels
If you’re at risk for a circulatory system disease, work with your doctor to control
conditions such as high blood pressure, high cholesterol, and diabetes. You can also take
steps and make lifestyle changes to prevent these conditions.
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√
Have a balanced diet each meal. A balanced diet gives you the correct food in
proper amount.
√
Watch your weight to prevent obesity. Obesity overworks the heart.
√
Exercise regularly. You need active exercise to make your bones and muscles firm
and strong.
√
Have time to rest to keep your heart from breaking down from fatigue.
√
Avoid stress. Avoid worrying too much.
√
Do not smoke or drink liquor.
√
Stay away from prohibited drugs.
√
Get fresh air every day. The fresh air that you breathe gives quick help to the
muscles of your heart.
√
Stand and sit with good posture so that your lungs and heart have room to work
properly.
√
Visit the doctor at least once a year for a health examination.
√
Reduce or Avoid Fatty Foods
-
Your body produces the right amount of cholesterol to maintain your health.
Cholesterol is a fatty or oily substance that normally forms part of your cell
wall. However, if the cholesterol level of your body gets high, it stays in the
walls of the arteries. It contributes to the condition called arteriosclerosis
or the hardening of the arteries causing heart attacks and strokes. Fatty
diets especially animal fats increase the cholesterol level. It is better to
replace the fats with carbohydrates such as bread, potatoes, and rice. Eat
less meat and more fish and poultry. Bad fats are found in beef, pork, lamb,
processed meats such as hotdogs and meat loaves.
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Assessment
I.
Identify what is/are asked. Write your answers on a separate sheet of paper.
___________________ 1. This is the circulation system that carries deoxygenated
blood to the lungs and returns oxygenated blood from the lungs back to the heart.
___________________ 2. This is the circulation system that carries oxygenated blood
throughout the body and returns the deoxygenated blood to the heart from the body
tissues.
___________________3. It is the measurement of how much force is used to pump
blood through your arteries.
___________________4. This heart ailment is also known as the “silent killer”.
___________________5. It is the fatty or oily substance that is normally forms part
of the cell wall but when consumed in excess contributes to the condition known as
arteriosclerosis.
II.
Using arrows, trace the path of blood from the heart to the rest of the body.
Write your answers on a separate sheet of paper.
The Path of Blood
Tricuspid Valve
Superior/Inferior Vena Cava
Right Atrium
Right Ventricle
Left Atrium
Rest of the Body
Left Ventricle
Pulmonary Valve
Pulmonary Artery
Aorta
Lungs
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ANSWER KEY
I.
1. Pulmonary Circulation
2. Systemic Circulation
3. Blood Pressure
4. High Blood Pressure
5. Cholesterol
II.
The Path of Blood
Tricuspid Valve
Superior/Inferior Vena Cava
Right Atrium
Right Ventricle
Left Atrium
Rest of the Body
Left Ventricle
Pulmonary Valve
Pulmonary Artery
Aorta
Lungs
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