By the end of this section you
should be able to:
1. State that the heart is a pump made of
muscle
2. State the function of heart valves
3. Measure your pulse rate to know your
heart rate
4. Know the normal range of resting heart
rates
5. Know that the heart has 4 chambers
The heart is made of
muscle.
When the heart
contracts, blood is
pumped into blood
vessels.
Arteries, called
coronary arteries,
supply the heart
muscle with blood and
oxygen
The heart has 4 chambers,
or spaces inside it.
It has 2 at the top (atria)
and 2 at the bottom
(ventricles).
Right
Atrium
Right
Ventricle
Left
Atrium
Left
Ventricle
During each heart beat, the muscle contracts
and pumps blood out of the chambers.
It contracts twice:
First one is the systole which is the
contraction of atria in order to pump
blood to the ventricles.
Second one is the diastole which is the
contraction of ventricles in order to pump
blood out of the heart (through arteries)
Valves in the heart keep the
blood flowing in one
direction only. When they
open and close you can
hear heart sounds using a
stethoscope.
One heartbeat
sounds like
“LUBB DUPP”
So!
LUBB DUPP, LUBB DUPP, LUBB DUPP
would be 3 heartbeats
The first sound “Lubb” is the sound of the
valves, that separate atria and ventricles,
closing down
That happens just
after the “systole”,
the contraction of the
atria, which allows
blood to flow to the
ventricles
Those are the valves responsible for the sound
The second sound “Dupp” is the sound of the
valves that avoid blood to flow down to the
ventricles closing down
That happens just after
the “diastole”, the
contraction of the
ventricles, which allows
blood to flow to the
arteries
Those are the valves responsible for the sound
Move your body and
try to hear your heart