Transcript File

What is this sound?
http://www.youtube.com/watch?v=7eFn8Cgcx8
g
Blood and the Heart
Learning Objective:
• To label and describe the roles of the
main parts of the heart (C)
• To explain the route of blood through
the transport system. (B)
• To describe double circulation (A)
The Circulatory System
The circulatory system is made up of:
• Blood
• Arteries
• Veins
• Capillaries
• The Heart
Why Does Our Heart
beat?
• To pump blood around the
body.
Why do we need to pump
blood around the body?
•To get oxygen to all the
organs and tissues in our
bodies.
What happens when we
run out of oxygen?
•We need to get more
How do we get more?
• The blood is pumped back to
our lungs.
• Where it is oxygenated again.
Where does it go from
here?
• Back to the heart.
Where does it go from
here?
• To the rest of the body.
Double circulatory system
lungs
body’s
cells
This is often
shown in a
diagram like
this
What happens at
each section?
See animation in
Go Science 2
p14/15
Double Circulation
• So we have two things going on in the heart,
this is known as double circulation.
• The blood is being pumped to the body to give
it oxygen AND the blood is being pumped to
the lungs to get more oxygen.
• So we say that the heart is spilt into two
sections, the left and the right.
4 Chambers
• Each side has two
chambers:
1. Atria at the top,
2. Ventricles are the
bottom.
What are their functions?
• Atria – Let blood pour into
heart and down into
ventricles.
• Ventricles - Blood from
ventricles pumped out of heat
when muscle contracts.
How do we stop the blood
from flowing backward?
• Valves stop the flow of blood once it
has entered the ventricles.
• And also once the blood has been
pumped out the valves stop it from
coming back into the heart.
TASK
•TASK : Label the diagram
of the heart with all the
key words.
In the Boxes:
•From Body
•To Lungs
•To Body
•From Lungs
Other:
•Right Atrium
•Right Ventricle
•Left Atrium
•Left Ventricle
•Valves
A real
heart
The Heart
•The heart is made of very special
muscle, CARDIAC muscle. It must
keep beating all the time for the
rest of a persons life! If you tried
to do the same action repeatedly
(like the heart) your muscles
would get tired and, after a while,
they would stop working.
•For example if you clench and
unclench your hand continuously,
it will get tired, and may even start
to cramp.
Structures of the heart
What are the stages in the cardiac
cycle?
The blood system
This is the
system which
carries the
dissolved food
and oxygen
around the
body. This
includes the
heart and the
lungs.
Blood cells provide oxygen and the plasma in the
blood carries dissolved food to ALL the cells in the
body.
Role of Blood
•Transport gases around the
body (oxygen and carbon
dioxide)
•Transport nutrients (i.e.
Glucose) around the body
Red Blood
Cells
Description
Diagram
Function
White Blood
Cells
Platelets
Plasma
Red Blood Cell
• Red blood cells have a perfect biconcave shape
for absorbing and releasing oxygen.
• Red blood cells are red only because they
contain a protein chemical called haemoglobin
which is bright red in colour.
• Haemoglobin contains the element Iron,
making it an excellent vehicle for transporting
oxygen.
• They also have no nucleus so they can transport
as much oxygen as possible.
There are approximately
five million red blood cells
per cubic millimetre of
blood, slightly more in
men and less in women.
The number of red
blood cells is higher in
people who live at high
altitudes.
Red blood cells do not
have nuclei.
Haemoglobin
• Haemoglobin is an amazing chemical
because if you warm it slightly and add
a bit of acid, it will give up all its
oxygen.
• As blood passes through the lungs,
oxygen molecules attach to the
haemoglobin.
• As the blood passes through the body's
tissue, the haemoglobin releases the
oxygen to the cells.
White Blood Cells
• There are usually a few thousand white blood
cells per cubic millimetre of blood.
• Their jobs are to produce antibodies and to
engulf bacteria, i.e. they fight disease.
Plasma
• Plasma is the liquid part of blood. It
contains many important substances
which must be carried around the body.




Products of Digestion (Glucose)
Carbon Dioxide
Hormones
Vitamins
• The plasma is a slightly yellowish in
colour.
Platelets
• To stop the loss of blood from
wounds
• Platelets form a clot which dries up
into a scab.
• This is quite a good thing because it
prevents any more blood from
getting out and it prevents germs
from getting in
Components of Blood
• red blood cells -transport of oxygen
• white blood cells -defence
• plasma -transport of food/waste
• platelets -blood clotting