Cardio Respiratory - Week 2 Mechanical Events of the Cardiac cycle Flashcards
Draw and label a Wigger’s diagram, ECG for the left side of the heart and volume changes for the left ventricle (5)
Check notes week 2 cardio respiratory pre work
Draw and describe Wigger’s diagram for Ventricular diastole (7)
Check notes week 2 cardio respiratory pre work
Heart is at rest
LA pressure > LV pressure
Therefore AV valve is open
Blood going into ventricle
Aortic pressure > LV pressure
Therefore semilunar valve is shut
Draw and describe Wigger’s diagram for atrial systole (7)
Check notes week 2 cardio respiratory pre work
Draw and describe earlier stages of ventricular systole (7)
Check notes week 2 cardio respiratory pre work
ECG – QRS complex
Q-R rapid depolarisation through
the bundle of His – bundle
branches toward the apex
R-S depolarisation spreads up the
wall of the heart
Ventricular depolarisation (leads to
ventricular contraction)
Ventricular pressure becomes
greater than atrial pressure
Mitral valve closes
First heart sound “lub”
(tricuspid valve also closes)
What happens during earlier stages of ventricular systole (5)
Aortic valve – Shut
Mitral Valve – Shut
Ventricles contract – left ventricular
pressure goes up
Ventricle is sealed so the volume
does not change ‘isovolumic’
Draw and describe ventricular systole (7)
Check notes week 2 cardio respiratory pre work
Ventricular contraction continues
Therefore, ventricular pressure
continues to rise.
When it exceeds the aortic pressure
the aortic (semilunar) valve opens
(i.e. pressure exceeds the
‘afterload’)
Blood can be ejected from the
ventricles into the aorta
Draw and describe latter stages ventricular systole (7)
Check notes week 2 cardio respiratory pre work
ECG – T wave
Ventricles repolarising
Therefore ventricles relax
Blood ‘attempts’ to flow back from
aorta into the ventricle
Ventricular pressure < aortic
pressure
Aortic valve closes
Draw and describe end of ventricular systole (7)
Check notes week 2 cardio respiratory pre work
Draw and describe early stages of ventricular diastole (7)
Check notes week 2 cardio respiratory pre work
Aortic valve – Shut
Mitral Valve – Shut
Ventricles relax– left ventricular
pressure goes down
Ventricle is sealed so the volume
does not change ‘isovolumic’
When does the metal valve open and where can this be seen on Wigger’s diagram? (3)
Check notes week 2 cardio respiratory pre work
When atrial pressure exceeds
ventricular pressure, mitral valve
opens
Draw and describe ventricular diastole (7)
Check notes week 2 cardio respiratory pre work
The valve opening allows blood
that has accumulated in the atria to
enter the ventricle
Both the atria and ventricle are
relaxed but…
Atrial pressure > ventricular
pressure
This begins a passive filling of the
ventricle during ventricular
diastole
