THE
CIRCULATO
RY SYSTEM
The role of the heart, blood
and blood vessels
WHAT IS YOUR
PULSE RATE?
To check your pulse, place the tips of your index
and middle finger on your wrist.
Feel your pulse and count the beats for 15 seconds.
Then, multiply that number by four to find out how
many times your heart beats in one minute.
Where does this pulse come from?
TODAY, YOU
WILL...
Name and describe the Describe the role of the
main parts of the human heart, blood and blood
circulatory system. vessels.
THE HUMAN
CIRCULATORY
SYSTEM
Function Main Parts
To transport blood, Has three main parts: the
oxygen and nutrients heart, blood vessels and
to the body blood
THE right atrium
left atrium
HEART
It works as a pump to move the
blood around the body.
It has four chambers—two atria
(upper chambers) and two
ventricles (lower chambers). right ventricle
left ventricle
THE HEART
Let’s examine how blood flows through the heart.
from upper
The right atrium takes in body
1 blood carrying carbon dioxide.
to left
lung
1
Blood is squeezed down into
2 the right ventricle and taken
to the lungs, where oxygen
replaces carbon dioxide. 2
THE
HEART
Let’s examine how blood flows through the heart.
Oxygen-carrying blood
to body 3 from the lungs enters
the left atrium.
3
from left lung Blood is pumped into
the left ventricle and
4 starts its journey again
4 throughout the body.
LESSON
CHECK:
THE HEART
Can you explain how blood flows
through the heart with a partner,
even without the diagram of the
heart?
Try explaining the process to your
peer without referring to your
notes.
SAMPLE ANSWER
LESSON
CHECK: body Right Atrium Left Atrium
lungs
THE HEART
Can you explain how blood flows
through the heart with a partner,
Right
even without the diagram of the Ventricle
Left Ventricle
heart?
Shown is a sample diagram of
how blood flows through the lungs body
heart.
BLOOD
It is a special fluid primarily
contained within the blood
vessels.
It has four main components—
red blood cells, white blood cells,
platelets and plasma.
BLOOD
Our blood has four main components:
Red Blood Cells Platelets
carry oxygen, gather at the site
nutrients and of injury and help
wastes the clotting
process
White Blood Cells Plasma
fight diseases and straw-coloured
protect the body liquid where the
from infection other components
float in
BLOOD
plasma
When someone has a blood test, a white blood cells
small amount of blood is taken and and platelets
kept in a tube for testing. red blood
cells
To closely examine it, blood
undergoes component separation.
One common method involves Blood is divided into its
spinning it at very high speeds in a components, with the heaviest
centrifuge. parts at the bottom.
BLOOD
VESSELS
These are tubes or channels that
carry blood throughout our body.
There are three types of blood
vessels—veins, arteries and
capillaries. Each one differs in
size and structure.
BLOOD
VESSELS
Let’s take a closer look at the three types of blood vessels:
It has the thickest wall of all three, allowing it to
Artery
withstand the high pressure created by the heart.
It has the thinnest wall to allow substances such as
Capillary oxygen and sugars to pass through its wall—into or
out of the blood.
It is less muscular and stretchy than an artery, so
Vein blood moves through it with low pressure. It also
has a special valve that helps blood go only one
way.
BLOOD
VESSELS
Each type of blood vessel has a unique role in the circulatory system.
Artery Capillary Vein
Carries blood Assists in the exchange Carries blood back
away from the of substances between towards the heart
heart the blood and tissues
TIP Remember ‘A’ for ‘artery’ and ‘away’ from the
heart!
LESSON CHECK:
SICKLE CELL
DISEASE
Sickle cell disease (SCD) is an inherited blood
disorder. People with SCD have red blood cells
that become hard and sticky, forming a C-
shaped blood cell instead of the healthy disc-
shaped one.
Considering what you’ve learnt about blood
and blood vessels, how does this shape affect
blood flow in the circulatory system?
SAMPLE ANSWER
LESSON CHECK:
SICKLE CELL
DISEASE
Considering what you’ve learnt about blood
and blood vessels, how does this shape affect
blood flow in the circulatory system?
The irregular shape of the sickle-shaped blood
cell makes it easy to clog and block the blood
flow.
This can cause pain and other serious
infections.
A
RECAP
The circulatory system delivers oxygen and
nutrients to the body, while also removing wastes.
Heart Blood Blood Vessels
Muscular organ that has Has four components: Has three types:
four chambers plasma, red blood cell, arteries, veins and
white blood cell and capillaries
Pumps blood around platelets
the body Serve as channels for
Carries oxygen, nutrients the blood
and wastes
A DAY IN THE LIFE OF A RED
BLOOD CELL
Write a story as though you are a red blood
cell.
Some guide questions you can use are:
• What do you look like?
• What is your job?
• Where are you found?
• Where do you travel from and to?
Try this background for online class.
*Please delete this section before downloading.
PRESS THESE KEYS while on
Present mode!
B for blur C for confetti
D for a drumroll M for mic drop
O for bubbles O for quiet
U for unveil 0-9 Any number from
0-9 for a timer
