An adrenergic fiber is one that

Question

Quizplus · Accepted Answer

An adrenergic fiber is defined as a nerve fiber that secretes the neurotransmitter norepinephrine (also known as noradrenaline). This means that the correct choice is D, which states that adrenergic fibers secrete norepinephrine as their transmitter. Choices A and B are incorrect, as adrenergic fibers do not necessarily innervate the adrenal medulla, nor are they always preganglionic fibers. Choice C is also incorrect, as there is no specific region of the brain known as the "midbrain" that is solely responsible for adrenergic signaling.

An Adrenergic Fiber Is One That