Cardiac Cycle Poster

The Cardiac Cycl
Semilunar valves




R Vena cava
Aorta




Pulmonary artery



PQRST = 1 cardiac cycle
P = atrial systole
caused by the depolarisation of the atria,
resulting in atrial contraction (systole)

QRS = ventricular systole
caused by the depolarisation of the ventricles,
which results in ventricular contraction Sino-atrial node
(systole). This is the largest wave because the
ventricles have the largest muscle mass (SAN)
T = diastole
caused by the repolarisation of the ventricles,
which results in ventricular relaxation (diastole) Right atrium


Tricuspid valve
(atrioventricular valve)



Ventricular
systole
Blood forced
out of
Aortic
Blood forced
ventricles
into aorta
pressure
Ventricular
pressure
Right
Ventricles
empty ventricle B
All blood
forced into
ia l
Atrioventricular node
ventricles Atr re
ssu (AVN) Apex
pre Diastole
Atrial Atrium begins
systole filling with blood




Stages of the Cardiac Cycle: Initiation
1. The sino-atria
1. The atria and ventricles relax at the same time
the wall of the
(diastole) wave of depol
2. The internal volume of the heart increases as contract.
blood flows in 2. An area of non
depolarisation
3. Blood flows into the atria from the vena cava and

ventricles.