NA 7- Vestibular system

The vestibule is located in the inner ear, anterior to the cochlea and posterior to the semicircular canals.

The recessus sphæricus is located on the medial wall of the vestibule, anterior to the crista vestibuli.

The fossa cochlearis, located inferior to the recessus sphæricus, is perforated by filaments of the vestibular nerve.

The recessus ellipticus, on the roof of the vestibule, contains an opening for the vestibular aqueduct and openings for nerves to the semicircular canals.

The saccule is situated within the recessus sphæricus and is connected anteriorly to the cochlear duct.

The utricle is continuous with the semicircular ducts and situated within the recessus ellipticus.

The semicircular ducts within the canals are identical in size to the bony canals they are contained within.

The membranous structures within the vestibular apparatus are filled with perilymph and surrounded by endolymph.

The utricle detects movement in the anteroposterior axis.

Ampullary crests are characterized by their location at the $ampulla$ and are covered by an otolithic membrane.

The endolymph movement inside the ampullary crest deflects the central core of the cupula, causing bending of the cilia.

When stereocilia move towards the kinocilium, a hyperpolarization is triggered.

Hair cells in the vestibular apparatus have only one type of receptor.

Maculae in the saccule and utricle differ in their orientation; the saccule is oriented horizontally, and the utricle vertically.

The posterior semicircular canal on one side is parallel to the anterior semicircular canal on the opposite side to form a functional couple.

The vestibular apparatus primarily detects linear acceleration.

The cranial nerve VIII is comprised of the vestibular nerve and the optic nerve.

The inferior branch of the vestibular nerve collects information entirely from the utricle and the superior semicircular canal.

The inner layer of the vestibular apparatus is composed of simple cuboidal epithelium.

The vestibular apparatus is part of the auditory system.

The vestibular apparatus relies solely on hair cells to detect movement.

Type 1 sensory cells are less discriminative due to their smaller afferent fibers.

The vestibular apparatus is solely responsible for detecting gravity.

All type 1 fibers within a macula or crest share the same polarization.

Type II sensory cells, unlike type 1, possess ordinary boutons and receive both afferent and efferent signals.

The vestibular nerve comprises approximately one-fourth of the cochlear nerve's size.

The macula is capable of detecting a constant, continuous acceleration of the head.

Fibers originating from the semicircular canals project exclusively to the superior vestibular nucleus.

The utricle is responsible for detecting vertical accelerations, while the saccule detects horizontal accelerations.

The lateral vestibular nucleus receives input from the utricle and saccule, but not the ampullary crests.

The continuous discharge frequency of maculae sensory cells is altered by the bending of cilia embedded within the otolithic membrane.

When stereocilia tilt in the same direction as the kinocilium, it leads to a hyperpolarization of the sensory cell.

Fibers from the vestibular organs projecting to the cerebellum exclusively form the juxtarestiform body.

The striola within the macula, formed by supporting cells, serves as a landmark for identifying the midline and the orientation of kinocilia in type 1 sensory receptors.

All juxtarestiform body fibers are ipsilateral, meaning they connect to the same side of the cerebellum.

The ampullary crest is responsible for detecting linear acceleration of the head, similar to the macula.

The superior and lateral vestibular nuclei contribute the majority of fibers ascending to the cortex.

Fibers from these nuclei primarily enter the ventral-posterior medial nucleus of the thalamus.

The semicircular ducts can provide a continuous sensation of movement, unlike the macula which only senses the beginning and end of the head tilt.

Vestibulo-ocular reflexes are primarily mediated by connections between vestibular nuclei and cranial nerves III, IV, and VI.

The orientation of the semicircular ducts within the three spatial axes allows for an understanding of head position, even without visual cues.

The medial vestibulospinal tract, originating from the medial vestibular nucleus, is responsible for maintaining posture by descending to the level of the mid-thoracic region.

The information reaching the primary somatosensory cortex regarding head position is solely conveyed via ascending pathways.