Question

considering that the hearts intrinsic (natural) rate is 100 beats per min (bpm), a normal resting heart rate of 70 bpm suggests which of the following?

a.) somatic reflex tone

b.) sympathetic and parasympathetic tone

c.) sympathetic tone

d.) parasympathetic tone

Explanation:

The parasympathetic nervous system (PNS) slows the heart rate. Since the intrinsic heart rate (100 bpm) is higher than the resting heart rate (70 bpm), the PNS is actively reducing the heart rate. The somatic nervous system controls voluntary movements, not heart rate. Sympathetic nervous system (SNS) increases heart rate. If both SNS and PNS (sympathetic and parasympathetic tone) were acting, it's less likely to have such a clear - cut decrease as the intrinsic rate is 100 and resting is 70. Parasympathetic tone alone (as it has a dominant effect at rest for heart rate regulation) is the best explanation.

Answer:

d. Parasympathetic Tone