Overview of the main chambers of the heart The left side is the thicker side because it has to pump blood all around the body The left side pumps blood that has oxygen in it to the body The right side pumps blood that has carbon dioxide in it to the lungs. The heart pumps by squeezing it’s walls which are thick muscles.
Get some real sheep’s hearts from the butcher for the students to examine. Give them 2 hearts per group: One cut in half to see the inside chambers and one left intact to see the overall size and muscularity of the heart.
red blood cells white blood cells
Functions of Blood System
• Transport: to and from tissue cells
– • Nutrients to cells: amino acids, glucose, vitamins, minerals,
lipids (as lipoproteins).
– • Oxygen: by red blood corpuscles (oxyhaemoglobin - 4 x O2
– • Wastes from cells: urea, CO2 (mainly as HCO3 in solution in
• Temperature Regulation: by altering the blood flow
through the skin.
• Immunity: protection against pathogens — blood
clotting; phagocytes, lymphocytes and antibodies
distributed in blood.
• Communication: hormones distributed to all parts of the
body in the blood.
• Defence: clotting following a wound
red blood cell white blood cell
Red Blood Cells
contain haemoglobin, a
molecule specially designed
to hold oxygen and carry it
to cells that need it.
can change shape to an
amazing extent, without
breaking, as it squeezes
single file through the
a biconcave disc that is
round and flat without a
White Blood Cells
there are many different types and
all contain a big nucleus.
the two main ones are the
lymphocytes and the macrophages.
some lymphocytes fight disease by making antibodies to destroy
invaders by dissolving them.
other lymphocytes make antitoxins to break down poisons.
macrophages ‘eat’ and digest micro-
Platelets are bits of cell
broken off larger cells.
fibres to form a net.
This net traps other
blood cells to form a
cells and the
• carbon dioxide
• amino acids
• waste materials
It also contains useful
The circulatory system carries blood and dissolved
substances to and from different places in the body.
Function of the
The Heart pumps blood and substances around the
body in tubes called blood vessels.
The Heart has the job of pumping these things around
The Heart and blood vessels together make up the
head & arms
How does this system work?
Our circulatory system is a double circulatory system.
This means it has two parts.
the right side of
the left side of
Why do we say we have a double
What is the Pulmonary circuit?
What is the Systemic circuit?
Answer these questions:
blood from the heart gets around
the body through blood vessels
There are 3 types of blood vessels
thick muscle and
Arteries carry blood away from the heart.
the elastic fibres allow
the artery to stretch
the thick muscle can
contract to push the
Veins carry blood towards from the heart.
thin muscle and
veins have valves
which act to stop the
blood from going in
the wrong direction.
body muscles surround the veins
so that when they contract to
move the body, they also squeeze
the veins and push the blood along
Capillaries link Arteries with Veins
the wall of a capillary
is only one cell thick
they exchange materials
between the blood and
other body cells.
The exchange of materials
between the blood and the
body can only occur through
A collection of capillaries is known as a capillary bedcapillary bed.
Complete the following text:
Arteries take blood ______ from the heart. The walls of an artery
are made up of thick _________ walls and elastic fibres. Veins
carry blood ________ the heart and also have valves. The
_________ link arteries and veins, and have a one cell thick wall.
Blood is made up of four main things ______, the liquid part of the
blood; Red Blood Cells to carry ______; White Blood cells to protect
the body from disease and _________ to help blood clot.
Complete the table with the blood vessels differences.
Explanation of Heart
The heart has 4 chambers:
2 on the Right: received blood and 2 on the left: pumps the blood out
How does the heart pump?
Vein from Lungs
Artery to Head and BodyArtery to Lungs
Vein from Head and Body
How does the Heart work?
blood from the
The heart beat begins when the
heart muscles relax and blood
flows into the atria.
The atria then contract and
the valves open to allow blood
into the ventricles.
How does the Heart work?
How does the Heart work?
The valves close to stop blood
The ventricles contract forcing
the blood to leave the heart.
At the same time, the atria are
relaxing and once again filling with
The cycle then repeats itself.
What is DIASTOLE?
What is SYSTOLE?
• The time period when the heart
is in a state of relaxation
• It is a phase of the cardiac cycle
where the myocardium
• Your body has about 5.6 litres of blood.
• This 5.6 litres of blood circulates through the
body three times every minute.
• In one day, the blood travels a total of 19,000
that's four times the distance across the US
from coast to coast.
• The heart pumps around a third of a cup each
time it beats.