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Pages 40-45
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CIRCULATORY
SYSTEM
The Circulatory System
The circulatory system is made up of the heart and blood
vessels.
What is the function of the circulatory system?
It transports substances around the body in the blood.
Which substances are transported by the circulatory system?
examples include:
• oxygen
• carbon dioxide
• water
• hormones
• proteins
• glucose
The Circulatory System R L
The human circulatory system is an example of a double
circulatory system.
This means that it contains two circuits, and the blood
passes through the heart twice.
This prevents oxygenated and deoxygenated blood from
mixing.
The pulmonary circuit carries deoxygenated blood from
the body to the right side of the heart. From here, it is
pumped to the lungs.
The systemic circuit carries oxygenated blood from the
lungs to the left side of the heart. From here, it is pumped
around the rest of the body.
THREE MAJOR PARTS OF THE
CIRCULATORY SYSTEM
1. BLOOD
https://www.youtube.com/watch?v=VSVYgivfs9c
1L 1L
1L 1L
1L 1L
1L 1L
1L 1L
0.5 L
COMPOSITION OF BLOOD
PLASMA
BLOOD CELLS
The Circulatory System
Plasma
The yellow, liquid component of blood that carries red blood cells, white blood
cells and platelets.
It also transports hormones, the soluble products of digestion and waste
products, such as urea and carbon dioxide.
x
L EUCOCYTES E RYTHROCYTES THROMBOCYTES
PARAMETERS RBC WBC
COLOR Red Colorless
SIZE Smaller Larger
Circular, flattened Amorphous
SHAPE
and biconcave disc
NUCLEUS Absent Present
HEMOGLOBIN Present Absent
Bone marrow ; mature
ORIGIN Bone marrow
in lymph organs
LIFE SPAN 120 days Few days
Help defend our body
from diseases
The Circulatory System
White Blood Cell
A specialised cell that forms part
of the immune system which
helps to defend the body against
disease.
They include phagocytes and
lymphocytes.
The Circulatory System
Red Blood Cell
A specialised cell containing
haemoglobin that transports
oxygen around the body.
It has a biconcave disc shape and
no nucleus.
THROMBOCYTES - help the blood to clot
The Circulatory System
Platelets
Small fragments of cells that help
blood to clot at the site of a
wound.
FUNCTIONS OF THE BLOOD
Transports gases, nutrients,
waste products and hormones Maintains water balance and pH Distributes antibodies for immunity
Destroys foreign materials Carries platelets for clotting Regulates body temperature
2. BLOOD VESSELS
https://www.youtube.com/watch?v=5EiDGEJPK70
Blood Vessels
Blood vessels form a major part of the
circulatory system. They transport blood and
other substances around your body.
By the time you are an adult, your body
contains around 60 000 miles of blood vessels.
There are three main types of blood vessels:
1. arteries
2. veins
3. capillaries
Arteries
Arteries carry blood away from the heart under
high pressure.
They have thick, elastic, muscular walls.
The lumen, which is the space in the blood
vessel through which blood is transported, is
narrow.
narrow lumen thick wall
These adaptations allow arteries to carry blood
at a high pressure without becoming damaged.
Veins
Veins carry blood towards the heart
under low pressure.
They have much thinner muscular walls
compared to arteries.
The lumen is wide in veins.
valve
Many veins contain valves. These
prevent the backflow of blood. wide lumen thinner wall
These adaptations allow veins to
passively transport blood back to the
heart without it pooling in your legs.
Capillaries
Capillaries connect arteries and veins. Many capillaries form a capillary network.
The walls of capillaries are only one cell thick.
Many capillaries have a lumen so small that blood cells flow through in single file.
These adaptations make capillaries an efficient exchange surface. Gases and
nutrients can pass through their walls quickly and easily.
artery
vein
capillary
network
What Blood Vessels Do
Arteries – carries oxygenated blood away from the heart
Capillaries – enable exchange of oxygen with body
Veins – carries blood from capillaries back to the heart to be pumped to the lungs to
be re-oxygenated.
capillaries
vein
artery
3. HEART
https://www.youtube.com/watch?v=GMBSU-2GK3E
1 2
3 4
The Function of the Heart
aorta
The heart is a powerful muscle
that is situated between your
pulmonary
lungs, protected by the ribcage. aortic valve
artery (left)
The right side pumps left
pulmonary
deoxygenated blood to the veins
lungs to get oxygen.
right atrium left atrium
The left side pumps the
oxygenated blood to the rest of left ventricle
the body. right ventricle
How the Heart Works
Click to go through each
stage of the process.
right atrium
right ventricle
pulmonic valve
pulmonary artery (left)
left pulmonary veins
left atrium
left ventricle
aortic valve
aorta
The Circulatory System
Atrium
Two of these small chambers
are found at the top of the
heart.
The right chamber receives
deoxygenated blood from the
vena cava. x
The left chamber receives
oxygenated blood from the
pulmonary vein.
The Circulatory System
Vena Cava
This blood vessel carries
deoxygenated blood from the
body to the right atrium in the
heart. x
The Circulatory System
Pulmonary Artery x
This blood vessel carries
deoxygenated blood from the
right ventricle in the heart to
the lungs.
The Circulatory System
Pulmonary Vein
This blood vessel carries
oxygenated blood from the
lungs to the left atrium in the
x
heart.
The Circulatory System
Aorta x
This blood vessel carries oxygenated
blood from the left ventricle in the heart
to the rest of the body.
ATRIA
Right Atrium Left Atrium
SEPTUM
Left Ventricle
Right Ventricle
VENTRICLES
VALVES
BLOOD FLOW
TYPES OF CIRCULATION
Pulmonary
Systemic
Coronary
TYPES OF CIRCULATION
Pulmonary from the heart to the rest of the body,
excluding the lungs
Systemicfrom the heart, to the lungs,
and back to the heart
Coronary through the tissues of the heart
1. What is the function of the circulatory
system?
2. Circulatory system is alco called as
________________.
3. What are the 3 components of the circulatory
system?
4. What are the 3 types of blood vessels and
briefly describe each.
5. List the components of the blood and their
scientific terms.
6. Draw and label the 4 chambers of the heart.
7. Enumerate the 3 blood vessels and give their
functions.
