Final answer:
The Sinoatrial (SA) Node sets the normal pace of the heart at 80-100 beats per minute. During strenuous exercise with a heart rate of 150 beats per minute, the time per beat is 0.4 seconds.
Step-by-step explanation:
The Sinoatrial (SA) Node is responsible for setting the pace of your heartbeat. Normally, without any extrinsic nervous or endocrine influence, the SA node generates an impulse to initiate a heart contraction 80-100 times per minute. The SA node's inherent rate of depolarization is the highest among the heart's conduction system components, hence it's known as the pacemaker of the heart. During strenuous exercise, a heart rate can increase significantly. If we consider a heart rate of 150 beats per minute during exercise, we can calculate the time per beat in seconds by dividing 60 seconds by the number of beats per minute.
To find the time per beat:
Time per beat (seconds) = 60 seconds / 150 beats per minute = 0.4 seconds per beat.
The Sinoatrial (SA) Node, often referred to as the heart's pacemaker, dictates the rhythmicity of cardiac contractions. In the absence of extrinsic nervous or endocrine influences, the SA node autonomously generates impulses, initiating heart contractions at a baseline rate of 80-100 times per minute. This intrinsic rate of depolarization in the SA node is the highest among the components of the heart's conduction system. During periods of strenuous exercise, the heart rate escalates significantly. For instance, with a heart rate of 150 beats per minute during exercise, the time per beat can be calculated by dividing 60 seconds by the beats per minute. The resulting time per beat is 0.4 seconds. This calculation exemplifies the dynamic responsiveness of the SA node to physiological demands, illustrating how it adjusts the heart rate to meet the increased metabolic requirements during activities such as exercise.