vestibular nerve

Examples of vestibular nerve in the following topics:

• Vestibulocochlear (VIII) Nerve

  • The vestibulocochlear nerve (also known as the auditory vestibular nerve and cranial nerve VIII) has axons that carry the modalities of hearing and equilibrium.
  • It consists of the cochlear nerve that carries information about hearing, and the vestibular nerve that carries information about balance.
  • The vestibulocochlear nerve consists mostly of bipolar neurons and splits into two large divisions: the cochlear nerve and the vestibular nerve.
  • The vestibular nerve travels from the vestibular system of the inner ear.
  • An illustration of the inner ear showing its semicircular canal, hair cells, ampulla, cupula, vestibular nerve, and fluid.

• Sensory Modalities

  • A message is sent to a neuron called the bipolar cell through the use of a nerve impulse.
  • The organ of equilibrioception is the vestibular labyrinthine system found in both of the inner ears.
  • The vestibular nerve conducts information from sensory receptors in three ampulla, each of which sense fluid motion in three semicircular canals caused by a three-dimensional rotation of the head.
  • The vestibular nerve also conducts information from the utricle and the saccule; these contain hair-like sensory receptors that bend under the weight of otoliths (small crystals of calcium carbonate) that provide the inertia needed to detect head rotation, linear acceleration, and the direction of gravitational force.
  • Nociception (physiological pain) signals nerve or other tissue damage.

• Pons

  • The alar plate produces sensory neuroblasts, which will give rise to the solitary nucleus and its special visceral afferent column, the cochlear and vestibular nuclei (which form the special somatic afferent fibers of the vestibulocochlear nerve), the spinal and principal trigeminal nerve nuclei (which form the general somatic afferent column of the trigeminal nerve), and the pontine nuclei, which is involved in motor activity.
  • Basal plate neuroblasts give rise to the abducens nucleus (forms the general somatic efferent fibers), the facial and motor trigeminal nuclei (form the special visceral efferent column), and the superior salivatory nucleus, which forms the general visceral efferent fibers of the facial nerve.
  • A number of cranial nerve nuclei are present in the pons:
  • The chief or pontine nucleus of the trigeminal nerve sensory nucleus (V)- mid-pons
  • The functions of the four nerves of the pons include sensory roles in hearing, equilibrium, taste, and facial sensations such as touch and pain.

• Functions of the Brain Stem

  • The brainstem gives rise to cranial nerves 3 through 12 and provides the main motor and sensory innervation to the face and neck via the cranial nerves.
  • Though small, it is an extremely important part of the brain, as the nerve connections of the motor and sensory systems from the main part of the brain that communicate with the peripheral nervous system pass through the brainstem.
  • In addition, upper motor neurons originate in the brain stem's vestibular, red, tectal, and reticular nuclei, which also descend and synapse in the spinal cord.
  • Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves, which emerge from segments of the spinal cord.
  • In humans, there are traditionally twelve pairs of cranial nerves.

• Development of Hearing and Balance

  • Critical periods have been identified for the development of the hearing and vestibular system.
  • The vestibular wall will separate the cochlear duct from the perilymphatic scala vestibuli, a cavity inside the cochlea.
  • Critical periods have been identified for the development of hearing and the vestibular system.
  • Animals with abnormal vestibular development tend to have irregular motor skills.
  • Studies have consistently shown that animals with genetic vestibular deficiencies during this critical period have altered vestibular phenotypes, most likely as a result of lack insufficient input from the semicircular canals and dopaminergic abnormalities.

• Parts of the Cerebellum

  • Its primary connections are with the vestibular nuclei, although it also receives visual and other sensory input.
  • It receives proprioception input from the dorsal columns of the spinal cord (including the spinocerebellar tract) and from the trigeminal nerve, as well as from visual and auditory systems.

• Reticular Formation

  • The lateral reticular formation is close to the motor nuclei of the cranial nerves and mostly mediates their function.
  • The nuclei can be differentiated by function, cell type, and projections of efferent or afferent nerves.
  • The reticular formation also relays eye and ear signals to the cerebellum so that visual, auditory, and vestibular stimuli can be integrated in motor coordination.
  • The nerve fibers in these pathways act in the spinal cord to block the transmission of some pain signals to the brain.

• Trochlear (IV) Nerve

  • The trochlear nerve (cranial nerve IV) is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye.
  • The trochlear nerve (cranial nerve IV) is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye.
  • The trochlear nerve is unique among the cranial nerves in several respects.
  • Other than the optic nerve (cranial nerve II), it is the only cranial nerve that decussates (crosses to the other side) before innervating its target.
  • Lesions of all other cranial nuclei affect the ipsilateral side (except of course the optic nerve, cranial nerve II, which innervates both eyes).

• Accessory (XI) Nerve

  • The accessory nerve (cranial nerve XI) controls the muscles of the shoulder and neck.
  • The accessory nerve (cranial nerve XI) controls the sternocleidomastoid and trapezius muscles of the shoulder and neck.
  • Unlike the other 11 cranial nerves, the accessory nerve begins outside the skull.
  • Due to its unusual course, the accessory nerve is the only nerve that enters and exits the skull.
  • However, more modern characterizations of the nerve regard the cranial component as separate and part of the vagus nerve.

• Brief Overview of Cranial Nerves

  • Cranial nerves are the nerves that emerge directly from the brain (including the brainstem).
  • The terminal nerves, olfactory nerves (I) and optic nerves (II) emerge from the cerebrum or forebrain, and the remaining ten pairs arise from the brainstem, which is the lower part of the brain.
  • The optic nerve (II): This nerve carries visual information from the retina of the eye to the brain.
  • The abducens nerve (VI): A motor nerve that innervates the lateral rectus muscle of the eye, which controls lateral movement.
  • The hypoglossal nerve (XII): This nerve controls the tongue movements of speech, food manipulation, and swallowing.