Final answer:
The tensor tympani and stapedius muscles help regulate pressure in the inner ear, with the former innervated by the trigeminal nerve (CN V) and the latter by the facial nerve (CN VII). The Eustachian tube assists in equalizing air pressure. The vestibulocochlear nerve (CN VIII) transmits auditory and equilibrium sensations from the inner ear to the brain.
Step-by-step explanation:
The muscle responsible for releasing pressure in the inner ear is the tensor tympani. It functions by contracting to dampen the vibrations of the eardrum and protect the inner ear from loud sounds. The tensor tympani muscle is innervated by a branch of the trigeminal nerve (CN V), specifically the mandibular branch. Additionally, the stapedius muscle, innervated by the facial nerve (CN VII), helps protect the inner ear by reducing the movement of the stapes bone in response to loud noises, thus regulating the pressure transmitted to the cochlea. The Eustachian tube, which is not a muscle, also plays a significant role in equalizing air pressure in the middle ear with the atmospheric pressure outside, keeping the pressure on both sides of the eardrum equal and allowing for proper vibration and sound transmission.
Conditions such as Ménière's disease can result in increased pressure within the inner ear, affecting hearing and balance. The vestibulocochlear nerve (CN VIII) is responsible for carrying both equilibrium and auditory sensations from the inner ear to the medulla, but it does not supply the muscles that help in pressure regulation; its primary function is in sensory transmission.