Question

The split up of time cycle of cardiac cycle

• A. VS-0.3 sec VD-0.5 sec AS-0.1sec AD-0.7 sec
• B. VS-0.5 sec VD-0.3 sec AS-0.7 sec AD-0.1 sec
• C. VS-0.3 sec VD-0.5 sec AS-0.5 sec AD-0.3 sec
• D. VS-0.5 sec AD-0.3 sec AS-0.3 sec AD-0.5 sec

Answer 1

The Correct Option is A

The cardiac cycle consists of systole (contraction) and diastole (relaxation) phases of the atria and ventricles. Here, we break down the time each phase occupies during a single cardiac cycle, lasting approximately 0.8 seconds in humans: 

• Ventricular Systole (VS): This is when the ventricles contract to pump blood into the pulmonary artery and aorta. The typical duration is 0.3 seconds.
• Ventricular Diastole (VD): This phase involves the ventricles relaxing and filling with blood. It lasts around 0.5 seconds.
• Atrial Systole (AS): During this phase, the atria contract to push blood into the ventricles and lasts for about 0.1 seconds.
• Atrial Diastole (AD): In this phase, the atria relax and fill with blood; it lasts approximately 0.7 seconds.

The correct option from the provided choices is: VS-0.3 sec VD-0.5 sec AS-0.1 sec AD-0.7 sec. Here is why this option is correct:

1. \(AS = 0.1 \, \text{sec}\) and \(AD = 0.7 \, \text{sec}\): The atrial systole and diastole last 0.1 and 0.7 seconds respectively, aligning with the typical phases of an atrial cycle.
2. \(VS = 0.3 \, \text{sec}\) and \(VD = 0.5 \, \text{sec}\): Ventricular systole typically lasts 0.3 seconds followed by diastole lasting 0.5 seconds, completing the ventricular cycle.

Other options do not match the typical physiological timing of a human cardiac cycle. Here is a basic breakdown of the phases:

Phase	Duration (seconds)
Atrial Systole (AS)	0.1 sec
Atrial Diastole (AD)	0.7 sec
Ventricular Systole (VS)	0.3 sec
Ventricular Diastole (VD)	0.5 sec
Total Cycle Duration	0.8 sec

Understanding the durations of each phase helps in accurately analyzing heart function and diagnosing related pathologies.