1.4 i) Know the cardiac cycle (atrial systole, ventricular systole and cardiac diastole) and relate the structure and operation of the mammalian heart, including the major blood vessels, to its function. ii) Know how the relationship between heart structure and function can be investigated practically.

the heart 



the right side of the heart is shown on the left of the diagram. The left side is on the right side of diagrams.

the left side- oxygen rich blood (thicker walls)
the right side- deoxygenated blood 

tricuspid- right 
bicuspid- left 

both are also known as atrioventricular valves.

atria- collect blood 
ventricles- pump blood

deoxygenated blood enters the body into the right atrium through the superior vena cava. 
oxygenated blood enters the left atrium from the lungs through the left pulmonary veins  

right atrium contracts to pump blood through the tricuspid valve into the right ventricle
left atrium contracts to pump blood through the tricuspid valve into the left ventricle

right ventricle contracts semilunar valve opens and deoxygenated blood travels to the lungs 

cardiac cycle

diastole: the heart ventricles are relaxed and the heart fills with blood. 
systole: ventricles contract and pump blood to the arteries. 

the events that occur in the first and second diastole phases actually happen at the same time. The same is also true for the events of the first and second systole phases

1st diastole phase
heart is relaxed, atrioventricular valves are open
De-oxygenated blood from the superior and inferior vena cava flows into the right atrium. blood to passes through to the ventricles