Final answer:
The nerve responsible for sympathetic control of the arrector pili smooth muscle is the postganglionic sympathetic nerve fibers. These fibers are part of the autonomic nervous system's fight-or-flight response, which leads to physiological changes such as goosebumps. The correct answer to the question is therefore (D) Postganglionic sympathetic nerve fibers.
Step-by-step explanation:
The nerve that has sympathetic control of the arrector pili smooth muscle, which is responsible for causing goosebumps, is part of the postganglionic sympathetic nerve fibers. These fibers are part of the sympathetic nervous system, originating from the spinal cord and relaying in sympathetic ganglia before reaching the target organ, such as the arrector pili muscle in the skin. The arrector pili are small muscles attached to hair follicles which contract in response to emotional states and cold, creating the appearance of goosebumps as a part of the body's sympathetic 'fight-or-flight' response. The correct answer to the question is therefore (D) Postganglionic sympathetic nerve fibers.
The sympathetic branch of the autonomic nervous system is designed for rapid response to stress, characterized by the release of neurotransmitters like norepinephrine, leading to the activation of various physiological responses. Although sympathetic preganglionic fibers do exist, they are involved in innervating sympathetic ganglia. Postganglionic fibers are the ones that actually reach and control the effector organs, such as the arrector pili muscles. The vagus nerve (A) is largely parasympathetic, the phrenic nerve (B) controls the diaphragm, and the sciatic nerve (C) is a sensory and motor nerve associated with the lower limb.