Question

1. Compare atrial and ventricular systole and diastole

Answer 1

Contraction of atria is known as atrial systole; while the contraction of ventricles is known as ventricular systole.

During atrial systole, The atria contracts- the heart beat starts. Both left and right contract together. The contraction creates small increase in pressure, helps to push blood into ventricles.  In an ECG, atrial systole is associated with atrial depolarization, or the P wave deflection

During ventricular systole, pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle. In this for short period of time all four valves closed.  In an ECG  the beginning of ventricular systole is marked by the deflections of the QRS complex.

Relaxation of atria is known as atrial diastole and relaxation of ventricles is known ventricle diastole

Atrial diastole is the very first event of the cardiac cycle, During atrial diastole, blood enters the right atrium through the superior and inferior vena cava and the left atrium via the pulmonary veins.During this stage Atrioventricular valves open

Ventricular diastole is the period during which the two ventricles are relaxing,it follows repolarization of the ventricles and is represented by the T wave of the ECG. During the early stages of ventricular diastole, both the atrioventricular and semilunar valves are closed. During this phase, there is no change in the amount of blood in the ventricle, but there is a precipitous fall in the intraventricular pressure. This is known as isovolumetric relaxation.