If the vagal nerves to the heart were cut,the result would be that ________.
A) the heart rate would increase by about 25 beats per minute
B) parasympathetic stimulation would increase, causing a decrease in heart rate
C) the atrioventricular (AV) node would become the pacemaker of the heart
D) the heart would stop, since the vagal nerves trigger the heart to contract

Question

Quizplus · Accepted Answer

The vagal nerves (parasympathetic nervous system) provide inhibitory input to the heart, slowing down the heart rate. If the vagal nerves were cut, this inhibitory input would be removed, leading to an increase in heart rate, by about 25 beats per minute. Therefore, choice A is the correct answer. Choice B is incorrect since an increase in parasympathetic stimulation would lead to a decrease in heart rate, not an increase. Choice C is incorrect since the AV node is not capable of becoming the pacemaker of the heart. Choice D is incorrect since the heart does not rely solely on vagal nerves to contract, and there are other mechanisms involved in initiating and maintaining heart contractions.

If the Vagal Nerves to the Heart Were Cut,the Result