Transcript KS4_The_Heart_and_Circulatory_System

KS4 Biology
The Heart and
Circulatory System
1 of 53
© Boardworks Ltd 2004
Contents
The heart and circulatory system
How are substances transported?
The heart: structure and function
The valves: structure and function
The action in motion
Multiple choice section
2 of 53
© Boardworks Ltd 2004
How are substances transported in our bodies?
The next organ system we will be considering can be
known by two names…..
Blood system
Circulatory system
The circulatory system is made of two parts:
1. The heart
2. The blood vessels
3 of 53
© Boardworks Ltd 2004
What we use in the air
One of the substances that the circulatory system
transports are respiratory gases.
For example, the oxygen that the body needs, must
be taken to the cells and the carbon dioxide waste
gas must be taken away from the cells.
4 of 53
© Boardworks Ltd 2004
Dissolved gases in blood
As these gases are carried by the blood, it means that in
terms of the presence of gas, we have two types of blood.
blood high in oxygen
blood low in oxygen
oxygenated
deoxygenated
At all times these two types of blood cannot mix.
Why do you think this is?
5 of 53
© Boardworks Ltd 2004
A double circulatory system
Because of this our circulatory system is in two parts.
It is in fact called a double circulatory system.
This section of the system
including the right side of
the heart, deals with the
deoxygenated blood.
Lungs
This section of the
system including the
left side of the heart,
deals with the
oxygenated blood.
Body cells
6 of 53
© Boardworks Ltd 2004
The human circulatory system
7 of 53
© Boardworks Ltd 2004
Contents
The heart and circulatory system
How are substances transported?
The heart: structure and function
The valves: structure and function
The action in motion
Multiple choice section
8 of 53
© Boardworks Ltd 2004
The heart: structure and function
In this unit we are going to
focus on the heart..
The Heart
This is the pump at the centre of the circulatory system.
Not all living organisms have hearts.
Also, the shape of the heart can change, depending on
what species you look at.
9 of 53
© Boardworks Ltd 2004
One big muscle
The heart is made almost entirely of muscle. It is unlike
any other muscle in your body because it never tires.
And even though it is full of blood it still needs it own
blood supply.
Oxygenated blood is carried to the heart by the
coronary arteries.
Each side of the heart has two chambers.
1. An top chamber or atrium and
2. A bottom chamber or ventricle
Each of these chambers has its own function.
Look at the diagram on the next slide to see what that is.
10 of 53
© Boardworks Ltd 2004
Diagrammatical representation
11 of 53
© Boardworks Ltd 2004
Contents
The heart and circulatory system
How are substances transported?
The heart: structure and function
The valves: structure and function
The action in motion
Multiple choice section
12 of 53
© Boardworks Ltd 2004
The valves: structure and function
Besides the chambers there is also another very important part
of the heart – the valves.
These valves are found between the top and bottom chambers
on both sides of the heart.
blood
valve
13 of 53
These valves are
rather like doors
that only open in
one direction.
© Boardworks Ltd 2004
Valves in action
As the atrium fills
with blood, the
valves are closed.
When the atrium
contracts and squeeze
the blood, the valves
are pushed open.
These valves are connected to the side wall of the heart
by tough tendons.
These tendons allow the valves to close but not invert.
14 of 53
© Boardworks Ltd 2004
Tendon holding a valve
valve
tendon
wall of
ventricle
These tendons can be compared to an arm holding
onto the handle of a door.
15 of 53
© Boardworks Ltd 2004
Analogy of a valve
The arm
bends
as the
door is
opened.
When the
door is
closed
the arm is
fully
extended.
It would be impossible for the door to open in the
other direction without the person moving with it.
The tendon (represented by the arm) is held in a fixed
position and therefore the valve (door) can only open
in one direction.
16 of 53
© Boardworks Ltd 2004
Preventing backflow
The blood will
naturally push
against the valve.
However, the
valves remain
firmly shut.
In this way, the blood can be moved from chamber to
chamber quite efficiently.
The valves prevent the blood from moving in the wrong
direction.
17 of 53
© Boardworks Ltd 2004
More valves
we also find
valves here
...and here!
These extra valves stop the blood from re-entering the
heart when it is pumped from the ventricles.
18 of 53
© Boardworks Ltd 2004
Lub - dub
When the blood knocks against the first heart valves, it
makes a ‘lub’ like sound.
When the blood knocks against the second set of
heart valves, it makes a ‘dub’ like sound.
artery
ventricle
The blood ‘slaps’ against
the valve and then passes
along the artery.
valve
These two sounds – lub and dub – are actually what we
hear as our heartbeat. So our heartbeat is in fact the
sound of the valves opening and closing.
19 of 53
© Boardworks Ltd 2004
The heart’s main valves
20 of 53
© Boardworks Ltd 2004
Contents
The heart and circulatory system
How are substances transported?
The heart: structure and function
The valves: structure and function
The action in motion
Multiple choice section
21 of 53
© Boardworks Ltd 2004
The action in motion
Now that we can name all of the parts of the heart it is
time to see how they work to push blood around the body.
The heart pumps blood when its muscle contracts. As
the muscle contracts the chamber gets smaller and
squeeze the blood out.
The two sides of the heart work together. The atria
contract and relax at the same time, as do the ventricles.
The next two slides describe what occurs inside the heart
during one heart cycle.
22 of 53
© Boardworks Ltd 2004
The action in motion
blood from the
body
blood from
the lungs
1. The heart beat begins
when the heart muscles
relax and blood flows into
the atria.
2. The atria then contract and
the valves open to allow
blood into the ventricles.
23 of 53
© Boardworks Ltd 2004
The action in motion
3. The ventricles contract
forcing the blood to leave the
heart. At the same time, the
atria are relaxing and once
again filling with blood.
The staged cycle then repeats itself.
24 of 53
© Boardworks Ltd 2004
Left and right ventricles
Do you notice anything
different about the two
sides of the heart?
Well, the left ventricle wall
is clearly thicker than the
right ventricle wall.
Why is this?
To answer this question, think about where the blood is
going when it leaves the right and left ventricles.
25 of 53
© Boardworks Ltd 2004
Different destinations
lungs
This journey is
far less
demanding. The
right ventricle
only has to pump
blood from the
heart to the
adjacent lungs.
This journey is
enormous.
The left
ventricle has
to pump blood
all over the
body!
body cells
Therefore, the left ventricle needs a thicker wall to
generate a stronger ‘squeeze’ on the blood.
26 of 53
© Boardworks Ltd 2004
Drag the labels to the correct numbered boxes
on the diagram of the blood system.
27 of 53
© Boardworks Ltd 2004
Traffic control
28 of 53
© Boardworks Ltd 2004
Label the heart
29 of 53
© Boardworks Ltd 2004
Answer the questions
30 of 53
© Boardworks Ltd 2004
Oxygenated or deoxygenated?
31 of 53
© Boardworks Ltd 2004
Getting things in order
32 of 53
© Boardworks Ltd 2004
Controlled circulation
33 of 53
© Boardworks Ltd 2004
Contents
The heart and circulatory system
How are substances transported?
The heart: structure and function
The valves: structure and function
The action in motion
Multiple choice section
34 of 53
© Boardworks Ltd 2004
Multiple choice section
Multiple choice questions
35 of 53
© Boardworks Ltd 2004
Q1
What is the alternative name for the blood
system?
A the heart system
B the circulatory system
C the transporting system
D the pumping system
36 of 53
© Boardworks Ltd 2004
Q2
Which of the following organs are found in
system?
the blood
A heart, lungs, brain and bladder
B arteries, heart and stomach
C arteries, veins and heart
D heart, veins and pancreas
37 of 53
© Boardworks Ltd 2004
Q3
The function of the circulatory system is to...
A transport substances, such as oxygen and dissolved
nutrients, around the body.
B support the movement of the body.
C digest large molecules of food.
D carry chemical messages between the brain and the
nerves.
38 of 53
© Boardworks Ltd 2004
Q4
What is the wall of the heart mainly made from?
A fat tissue
B skin tissue
C nerve tissue
D muscle tissue
39 of 53
© Boardworks Ltd 2004
Q5
The blood system is often known as the “double
circulation” system. Why is this?
A The blood carries two vital materials.
B There are actually two parts to the heart.
C The system is divided into two separate circuits.
D The blood flows in two directions.
40 of 53
© Boardworks Ltd 2004
Q6
How many chambers are there in the human heart?
A four
B it varies from human to human
C two
D none of the above
41 of 53
© Boardworks Ltd 2004
Q7
Look at the diagram below.
W
X
Y
Z
Name the chamber that is labelled W (be
careful!).
A the right ventricle
B the left ventricle
C the right atrium
D the left ventricle
42 of 53
© Boardworks Ltd 2004
Q8
If blood entered the chamber X, where would it then
go?
A It would leave the heart.
B It would pass into chamber Z.
W
X
Y
Z
C It would pass across into chamber W.
D It would flow into all the other chambers.
43 of 53
© Boardworks Ltd 2004
Q9
Which chamber is the left ventricle?
A W
W
X
Y
Z
B X
C Y
D Z
44 of 53
© Boardworks Ltd 2004
Q10
Which side of the heart has the thickest wall?
A the left
B the right
W
X
Y
Z
C both sides are the same thickness
D middle is thicker
45 of 53
© Boardworks Ltd 2004
Q11
Into which chambers does blood enter the heart?
A the right and left atrium
B the right and left ventricle
C the right atrium and the left ventricle
D the right ventricle and the left atrium
46 of 53
© Boardworks Ltd 2004
Q12
Through which two chambers does blood leave the
heart?
A the right and left atrium
B the right and left ventricle
C the right atrium and the left ventricle
D the right ventricle and the left atrium
47 of 53
© Boardworks Ltd 2004
Q13
Which of these combinations lists the two circuits
that blood makes through the body?
A Heart - Lungs - Body - Lungs
B Heart - Body - Heart - Body - Lungs
C Body - Lungs - Heart - Body - Heart
D Heart - Lungs - Heart - Body
48 of 53
© Boardworks Ltd 2004
Know what’s in your heart
Look at the diagram below.
P
S
Q
R
T
U
49 of 53
© Boardworks Ltd 2004
Part 1
What is part T?
A an atrium
P
S
B a ventricle
Q
R
C a capillary
T
D a chamber
U
50 of 53
© Boardworks Ltd 2004
Part 2
Part Q shows...
A a heart valve.
P
S
B the atrium.
Q
C a chamber.
D a heart door.
51 of 53
R
T
U
© Boardworks Ltd 2004
Part 3
Arrow R pumps blood to the...
A the ventricles.
P
S
B the body.
Q
R
C the liver.
T
D the lungs.
U
52 of 53
© Boardworks Ltd 2004
Part 4
Arrow P shows the blood coming from the...
A the stomach.
P
S
B the head.
Q
53 of 53
R
C the body.
T
D the lungs.
U
© Boardworks Ltd 2004