Final answer:
The intrinsic rate of the Purkinje system is B) 15-40 bpm. This rate is part of the heart's conduction system, which can operate independently but is usually modulated by the autonomic nervous system.
Step-by-step explanation:
The intrinsic rate of the Purkinje system is B) 15-40 bpm.
Each component of the heart's conduction system is capable of generating its own impulse, and the rate progressively slows as you proceed from the SA node to the Purkinje fibers. Without the higher pacemaker activity, the atrioventricular (AV) node would set a heart rate of 40-60 beats per minute. If the AV node were blocked, the atrioventricular bundle would fire at a rate of approximately 30-40 impulses per minute.
The intrinsic firing rates are influenced by the autonomic nervous system, where sympathetic activation can increase the heart rate, while parasympathetic activity usually slows it down.