Final answer:
The spinal accessory nerve is responsible for controlling neck muscles but does not innervate the muscles of the soft palate, pharynx, or taste buds.
Step-by-step explanation:
The spinal accessory nerve, or eleventh cranial nerve, is primarily responsible for the contraction of the neck muscles such as the sternocleidomastoid and trapezius muscles. It is not responsible for innervating the skeletal muscles of the soft palate, pharynx, nor for sensory impulses from taste buds. Instead, the glossopharyngeal nerve (ninth cranial nerve) and the vagus nerve play key roles in these functions. The glossopharyngeal nerve is involved in taste and sensation from the pharyngeal walls and can stimulate the gag reflex. The vagus nerve, which is part of the autonomic nervous system, directly stimulates the contraction of skeletal muscles in the pharynx and larynx, contributing to swallowing and speech functions. Testing for the function of these nerves involves specific maneuvers like introducing taste stimuli, checking the gag reflex, and asking a patient to repeat consonant sounds to observe muscle movements.