Circulatory System
CIRCULATORY SYSTEM
The circulatory system is a
network consisting of blood,
blood vessels, and the heart.
This network supplies tissues in
the body with oxygen and other
nutrients, transports hormones,
and removes unnecessary waste
products.
FUNCTIONS
● Helps the body maintain a
normal body temperature
● Fights off disease
● Provides the right chemical
balance to provide the body’s
homeostasis, or state of balance,
among all its systems
Oxygen enters the bloodstream
through tiny membranes in the lungs
that absorb oxygen as it is inhaled.
AMAZING FACTS ABOUT THE CIRCULATORY SYSTEM
●
●
●
Capillaries are quite tiny and are about 8
microns
in
diameter,
and
quite
interestingly, red blood cells are almost of
the same size as the capillaries.
Other cells in your body have nuclei, but
your red blood cells are different, because
they contain no nuclei and that's why they
can carry more oxygen.
There is no such thing as A "broken heart"
after an emotional setback. This experience
is known as "broken heart syndrome" which
is characterized by a sudden, temporary
weakening of the muscle of your heart.
Main Circulatory System Organs
1.The Heart
● It is made of specialized cardiac
muscle tissue that allows it to act as a
pump within the circulatory system
● It is divided into four chambers
wherein it is composed of 2 auricles
(top chambers which receives blood
from the veins) and 2 ventricles
(bottom chambers which pump
blood into arteries).
Main Circulatory System Organs
1.The Heart
● As blood leaves each chamber of the heart, it passes through valves
guarded by flaps or cusps.
● Four heart valves, namely the mitral valve, tricuspid valve, aortic
valve, and pulmonary valve, work to prevent blood from flowing in
the wrong direction.
● The valves open in one direction like trapdoors to let blood pass
through. Then they close, so blood cannot flow backwards into
auricles.
Aorta
● The largest artery in the body
● It begins at the top of the left ventricle,
the
heart’s
muscular
pumping
chamber.
● The heart pumps blood from the left
ventricle into the aorta through the
aortic valve.
● Three leaflets on the aortic valve open
and close with each heartbeat to allow
one-way flow of blood.
Pulmonary Trunk
●
●
●
A major vessel of the human heart that originates
from the right ventricle.
It branches into right and left pulmonary arteries
which leads to the lungs.
The function of these vessels is to transmit oxygendepleted, carbon dioxide-rich blood from the right
ventricle to the lungs.
Superior Vena Cava
● The superior of two venae cavae, the great
venous trunks that return deoxygenated
blood from the systemic circulation to the
right atrium of the heart.
● It is a vein that is short and has a large
diameter (24mm) that receives
venous
return from the upper half of the body,
above the diaphragm
● It is located in the anterior right superior
mediastinum
Inferior Vena Cava
● It is also known as the posterior vena cava
● It is a large diameter vein that is located posterior to the abdominal
cavity and runs along the right side (thus making it a
retroperitoneal structure), with the aorta lying laterally on the left of
the IVC.
● It is the result of two major leg veins coming together.
The iliac veins come together at the small of the back, at the fifth
lumbar vertebra. Once the iliac veins have merged, the inferior vena
cava begins to transport blood to the heart.
Atrium
●
●
●
It is the upper chamber through which blood
enters the heart.
It receives blood, and when the heart muscle
contracts they pump blood to the ventricles.
There are two atria in the human heart – the
left atrium connected to the lungs, and the
right atrium connected to the venous
circulation.
Ventricle
●
●
●
It is one of two large chambers toward the bottom
of the heart that collect and expel blood received
from an atrium towards the peripheral beds
within the body and lungs.
Right ventricle: Receives blood from the right
atrium and pumps it to the main pulmonary
artery.
Left ventricle: Receives blood from the left atrium
and pumps it to the aorta. Blood returning to the
heart from the lungs enters the left atrium and
passes through the mitral valve to the left
ventricle.
Pulmonary Veins
●
●
●
●
It is responsible for carrying oxygenated blood from the
lungs back to the left atrium of the heart.
This differentiates the pulmonary veins from other veins
in the body, which are used to carry deoxygenated blood
from the rest of the body back to the heart.
Humans have four pulmonary veins in total, two from
each lung.
Each pulmonary vein is linked to a network of capillaries
(small blood vessels) in the alveoli of each lung.
COMMON MISCONCEPTIONS
Arteries carry oxygenated blood and veins carry deoxygenated blood.
Pulmonary veins carry oxygenated blood towards the heart and the pulmonary
arteries carry deoxygenated blood away from the heart.
Blood is always red.
Veins can appear blue as we see them through our skin, leading some people to
believe that deoxygenated blood is blue. However, Blood only appears blue because
of the way tissues absorb light and our eyes see color. Although oxygen does have an
effect on the brightness of the blood (more oxygen makes a brighter red, less makes
it darker), blood is never actually blue.
Main Circulatory System Organs
2. The Blood and the Blood Vessels
● Blood from the heart is pumped
throughout the body using blood
vessels.
● Blood vessels allow blood to flow
quickly from one region to another
and then allows it to come back to
your heart.
● Blood vessels have a hollow area that
allows for easy flow of blood and it's
called lumen.
Red Blood Cells
These cells take oxygen from your lungs and
transport it to the rest of your body cells. After
delivering the oxygen, it gathers up the carbon
dioxide and delivers it back to your lungs.
White Blood Cells
These blood cells play a role in fighting off germs
and protect you from diseases. Your body
produces more white blood cells to deal with an
infection in your body.
Platelets
When
you
cut
yourself,
platelets start accumulating at
the opening and plug up the
hole brought about by a
wound to stop bleeding.
Once platelets start sticking to
the opening of a damaged
blood
vessel,
they
start
attracting
more
fibers,
platelets and other blood cells
to prevent excessive bleeding.
Plasma
The plasma transports your
blood cells, nutrients,
hormones, and many other
components throughout
your body
Three Basic Types of Blood Vessels
● Arteries take oxygen-rich blood
away from your heart.
● Veins take blood back toward your
heart.
● Capillaries are very tiny blood
vessels that form a connection
between arteries and veins. The
capillary walls facilitate the transfer
of oxygen, nutrients and wastes in
and out of your body.
The Lungs
● The lungs provide oxygen for the
body.
● It sends oxygen-rich blood to the
left side of your heart and your
heart then uses blood vessels and
arteries to transfer it to the rest of
your body.
CIRCULATIONS
The human circulatory system consists
of 3 major circuits:
●
The pulmonary circuit provides
blood flow between the heart and
lungs.
●
The systemic circuit allows blood
to flow to and from the rest of the
body.
●
The
coronary
circuit
provides blood to the heart.
strictly
Pulmonary
Circulation
It carries deoxygenated blood
away from the right ventricle of
the heart, to the lungs and
returns oxygenated blood to the
left atrium and ventricles of the
heart.
Systemic
Circulation
The systemic circulation provides the
functional blood supply to all body tissue. It
carries oxygen and nutrients to the cells
and picks up carbon dioxide and waste
products. Systemic circulation carries
oxygenated blood from the left ventricle,
through the arteries, to the capillaries in the
tissues of the body. From the tissue
capillaries, the deoxygenated blood returns
through a system of veins to the right
atrium of the heart.
Coronary
Circulation
It supplies blood to and
provides drainage from
the tissue of the heart.
Deoxygenated blood is
returned to the chambers
of the heart via coronary
veins.
DISEASES OF THE CIRCULATORY SYSTEM
Arteriosclerosis
● A general term for hardening and suffering
of arteries and arterioles.
● The fatty deposits in the arteries causes the
walls to stiffen and it increases the blood
pressure when the arteries of the kidney are
partially or completely blocked and thicken
the walls.
Hypertension
Commonly called “high blood
pressure”
It causes the heart to work
harder which leads to such
complications:
● Stroke
● Kidney Failure
● Heart Stroke
Aortic
Aneurysm
It occurs when the aorta is
damaged and start to bulge or
tear.
Causes:
● Severe internal bleeding
● Obesity
● High blood pressure
Peripheral
Arterial
Disease (PAD)
➔ It involves areas of narrowing
or blockage within an artery.
➔ It has narrowed arteries that
reduce blood flow to the
limbs.
➔ It build up fatty deposits in
the arteries
➔ It restricts blood supply to
legs
KEY TERMS: A SUMMARY
Cardiac - related to the heart
Pulmonary - related to the lungs
Artery - a blood vessel that moves blood away from the heart
Vein - a blood vessel that moves blood toward the heart
Aorta - major artery that carries blood to the systemic circulatory system
Capillary - small blood vessel that allows nutrient exchange
Atrium - upper chamber of the heart
Ventricle - lower chamber of the heart
3 Types of Circulation
1.
2.
3.
Matching Type
4. Take oxygen-rich blood away from your heart.
5. Take blood back toward your heart.
6. Are very tiny blood vessels that form a connection between arteries and
veins.
7. It prevents excessive bleeding.
Choices: Red Blood Cells, Capillaries, Arteries, Ventricle, Plasma,
White Blood Cells, Veins, Platelets
Matching Type
8. It transports your blood cells, nutrients, hormones, and many other
components throughout your body.
9. These cells take oxygen from your lungs and transport it to the rest of your
body cells.
10. These blood cells play a role in fighting off germs and protect you from
diseases.
Choices: Red Blood Cells, Capillaries, Arteries, Ventricle, Plasma,
White Blood Cells, Veins, Platelets
TRUE or FALSE
11. The circulatory system is a network consisting of blood, blood vessels, and
the heart.
12. Pulmonary Trunk is the major vessel of the human heart that originates
from the left ventricle.
13. Atrium is the lower chamber through which blood enters the heart.
14. Pulmonary Veins is responsible for carrying deoxygenated blood from the
lungs back to the left atrium of the heart.
15. Aorta is the largest artery in the body.
16.Oxygen enters the bloodstream through tiny membranes in the lungs that
absorb oxygen as it is inhaled.
17. It is made of specialized cardiac muscle tissue that allows it to act as a pump
within the circulatory system.
18. Blood vessels have a hollow area that allows for easy flow of blood and it's
called lumen.
19. Peripheral Arterial Disease occurs when the arterial is damaged and start to
bulge or tear.
20. Aortis Aneurysm cause the heart to work harder which leads to such
comlications like Stroke.
ANSWER KEY
3 Types of Circulation
1. Coronary Circulation
2. Pulmonary Circulation
3. Systemic Circulation
4. Take oxygen-rich blood away from your heart. Arteries
5. Take blood back toward your heart. Veins
6. Are very tiny blood vessels that form a connection between arteries and
veins. Capillaries
7. It prevents excessive bleeding. Platelets
8. It transports your blood cells, nutrients, hormones, and many other
components throughout your body. Plasma
9. These cells take oxygen from your lungs and transport it to the rest of your
body cells. Red Blood Cells
10. These blood cells play a role in fighting off germs and protect you from
diseases. White Blood Cells
11. The circulatory system is a network consisting of blood, blood vessels, and
the heart. TRUE
12. Pulmonary Trunk is the major vessel of the human heart that originates
from the left (right) ventricle. FALSE
13. Atrium is the lower (upper) chamber through which blood enters the heart.
FALSE
14. Pulmonary Veins is responsible for carrying deoxygenated (oxygenated) blood
from the lungs back to the left atrium of the heart. FALSE
15. Aorta is the largest artery in the body. TRUE
16.Oxygen enters the bloodstream through tiny membranes in the lungs that
absorb oxygen as it is inhaled. TRUE
17. It is made of specialized cardiac muscle tissue that allows it to act as a pump
within the circulatory system. TRUE
18. Blood vessels have a hollow area that allows for easy flow of blood and it's
called lumen. TRUE
19. Peripheral Arterial Disease (Aortic Aneurysm) occurs when the arterial is
damaged and start to bulge or tear. FALSE
20. Aortis Aneurysm (Hypertension) cause the heart to work harder which leads to
such comlications like Stroke. FALSE
References:
https://www.healthline.com/human-body-maps/circulatory-system#1
https://biologydictionary.net/circulatory-system/
https://www.wisegeek.com/what-are-the-parts-of-the-circulatory-system.htm
https://www.khanacademy.org/science/high-school-biology
https://www.kenhub.com/
https://www.livescience.com/22486-circulatorysystem.html?fbclid=IwAR2_VuyIjWMrUlSYZVkqjV41W9MYXcRl2b4iRu50JpRXpwy0UNUIQ6b9Vg4