The Vestibular System

Comprehensive vocabulary flashcards covering the anatomy, mechanics, and neural pathways of the vestibular system based on lecture notes.

Vestibular System

A sensory system consisting of three modalities of spatial orientation and five sensory organs that helps maintain balance and stabilize eyes during head motion.

Graviception

The sense of the relative orientation of gravity with respect to the organism.

Afferent

Neural connections that transmit signals from the senses to the brain.

Efferent

Neural connections that transmit signals from the brain to the muscles.

Linear motion

Translational motion or position change sensed by the otolith organ; also referred to as linear acceleration.

Angular motion

Rotational motion or acceleration sensed by the semicircular canals.

Tilt

The angle of the head tilt, sensed through gravity by the otolith organ.

Roll

Rotation around the x-axis.

Pitch

Rotation around the y-axis, such as when shaking the head to signal 'yes'.

Yaw

Rotation around the z-axis, such as when shaking the head to signal 'no'.

Hair cells

Mechanoreceptors for the vestibular system that code for amplitude and direction through depolarization and hyperpolarization.

Semicircular canals

Three membranous canals (anterior, posterior, and horizontal) attached to the cochlea that respond to angular acceleration.

Ampulla

A structure within the semicircular canals containing the cupula, crista, and hair cells where fluid movement bends hair cells.

Push-pull response

A coding mechanism where the canals in one ear depolarize while the canals in the other ear hyperpolarize.

Otolith organs

Two organs (utricle and saccule) that utilize cilia and otoconia to sense linear acceleration and gravity.

Otoconia

Calcium carbonate crystals embedded in a membrane over hair cell cilia within the otolith organs.

Utricle

An otolith organ primarily responsible for sensing horizontal linear motion.

Saccule

An otolith organ primarily responsible for sensing vertical linear motion.

Vection

The illusory feeling of self-motion when one is actually stationary, often triggered by visual stimuli like a rotating figure.

Sensory reafference

A change in afferent signals caused by self-generated activity.

Sensory exafference

A change in afferent signals caused by external stimuli.

Vestibulo-ocular reflexes (VORs)

Reflexive eye rotations in the opposite direction of head motion to maintain visual stability; part of the Autonomic Nervous System.

Vestibular nuclei of the pons

A neural relay point for the vestibular nerve that facilitates pathways for VORs and spatial orientation perception.

Ventral posterior nucleus (VPN) of the thalamus

A specific area of the thalamus involved in the neural pathway for spatial orientation perception.

Temporo-parieto-insular cortex

A cortical region involved in processing visual and vestibular information for spatial orientation perception.