3.1.5 Pressure and Volume Changes
in the Heart
L.O: to interpret graphs on the cardiac cycle
Starter: What animal has the highest blood
pressure in the whole wide world?
What’s the keyword?
Activity
1) Place your whiteboard on the table, use the
rulers as axes around the whiteboard
2) Divide the whiteboard into the three stages
of the cardiac cycle (start with atrial systole)
3) Use one piece of wool to show the pressure
changes in the atria
4) Use a different coloured piece of wool to
show the pressure changes in the ventricles
Extension: Can you redo step 2 to think about
how long each stage roughly lasts for?
Pressure Changes in the Heart
Atrial
Systole
Ventricular
Systole
Diastole
Pressure Changes in the Heart
Atrial
Systole
Ventricular
Systole
Atria pressure
increases due
to contraction
Diastole
Pressure Changes in the Heart
Atrial
Systole
Ventricular
Systole
Atria pressure
increases due
to contraction
Atria pressure
decreases as
atria relax
Diastole
Pressure Changes in the Heart
Atrial
Systole
Ventricular
Systole
Atria pressure
increases due
to contraction
Atria pressure
decreases as
atria relax
Diastole
Atria pressure
increases as
atria fill
Atrial
Systole
Ventricular
Systole
Diastole
Atrial
Systole
Ventricular
pressure
increases
slightly due
to passive
filling
Ventricular
Systole
Diastole
Atrial
Systole
Ventricular
Systole
Ventricular
pressure
increases
due to
contraction
Ventricular
pressure
increases
slightly due
to passive
filling
Diastole
Atrial
Systole
Ventricular
Systole
Ventricular
pressure
increases
due to
contraction
Ventricular
pressure
increases
slightly due
to passive
filling
Diastole
Ventricular
pressure
decreases
as ventricles
relax
Atrial
Systole
Ventricular
Systole
Ventricular
pressure
increases
due to
contraction
Ventricular
pressure
increases
slightly due
to passive
filling
Diastole
Ventricular
pressure
decreases
as ventricles
relax
Ventricular
pressure
increases
slightly due
to passive
filling
Volume Changes
150
Volume of
left
ventricle
100
(cm3)
0
0
0.1
0.2
0.3
0.4
0.5
Time (secs)
Atrial
Ventricular
Systole Systole
Ventricular
Diastole
0.6
0.7
0.8
Volume Changes
150
Thinking task!
What do you think
the line would look
like?
Volume of
left
ventricle
100
(cm3)
0
0
0.1
0.2
0.3
0.4
0.5
Time (secs)
Atrial
Ventricular
Systole Systole
Ventricular
Diastole
0.6
0.7
0.8
Volume Changes
150
Volume of
left
ventricle
100
(cm3)
0
0
0.1
0.2
0.3
0.4
0.5
Time (secs)
Atrial
Ventricular
Systole Systole
Ventricular
Diastole
0.6
0.7
0.8
Pressure Changes in the Heart
Match the letter on the graph to the following events
Semi-lunar valves open
Atrio-ventricular valves close,
Semi-lunar valves close
Atrio-ventricular valves open
atrio-ventricular valves close
semi-lunar valves open
atrio-ventricular valves close
semi-lunar valves open
semi-lunar valves close
atrio-ventricular valves close
semi-lunar valves open
semi-lunar valves close
atrio-ventricular valves close
atrio-ventricular valves open
I can describe the
three main stages of
the cardiac cycle
No
No
Yes
I can explain the how
the heart is controlled
by electrical impulses
Use the AS revision guide
page 40 and 41
to make notes
Can you see where you
went wrong? Ask me for help
Complete sheet B.
What was your score?
Yes
I can interpret
pressure and volume
graphs on the cardiac
cycle
Yes
No
Yes
Complete sheet A.
Did you score over 85% ?