C10- Vestibular System

When the body is still under gravity, otoliths don't move, causing no stimulation. This tells the brain we are stationary, even when ascending in a lift.

Standing still requires more stiffness to move otoliths, resulting in stronger deformation and stimulation. These movements are parallel to gravity.

Movement not parallel to gravity, like inside a car. The maculae are affected by the resulting vector of gravity, which changes based on movement direction.

Tilting the ground floor is a linear movement at an angle to gravity. Maculae detect all movement and position relative to the ground.

Due to the arrangement of cells in the macula, there are always receptors highly stimulated during any movement. This provides a double validation system for the brain.

The brain uses proprioception from the neck to differentiate between head movement and body movement.

vestibule information and proprioception from the neck are combined to determine the movement of the head alone

Vestibule information alone indicates movement of both the head and body.

The state where the semicircular canals are firing at their baseline rate when no movement is occurring.

The initial rapid change in firing rate of the semicircular canals when movement begins.

A gelatinous structure that sits on top of hair cells in the semicircular canals.

The fluid that fills the semicircular canals.

The bending of hair cells in the semicircular canals caused by the movement of the cupola.

The property of endolymph to resist changes in motion.

Receptors that respond to the onset (start) and offset (stop) of a stimulus.

The way the semicircular canals provide information about movement by detecting both the start and end of movement.

The ability of the brain to know the head's position in space by analyzing the firing rate of the semicircular canals when the head is still.

The semicircular canals monitor changes in head position by detecting the rapid changes in the fluid's movement.

Hair cells bend in one direction, increasing nerve firing rate. Bending in the opposite direction decreases firing rate.

Provides information about head position relative to gravity (static tilt) and linear motion in any direction.

Changes in fluid movement stimulate hair cells, sending signals to the brain.

Different from ON-center/OFF-surround, these cells provide information about light in the surround.

The brain must analyze gravity's force and orientation based on body movement, even when at rest.

Small particles within the otolithic organs that are influenced by gravity.

A gelatinous layer covering hair cells in otolithic organs, contributing to movement detection.

Changes in the fluid's properties (viscosity, stiffness) due to factors like temperature or alcohol can lead to false sensory input.

The brain needs both ON-center/OFF-surround and OFF-center/ON-surround cells to analyze light contrast.

The brain calculates the resulting force of gravity based on movement and its direction.

A gelatinous layer within the inner ear where otoliths are suspended. It moves with the otoliths, triggering hair cells.

Specialized sensory structures in the inner ear that detect linear acceleration and gravity.

The force exerted by the otoliths on the gelatinous layer, caused by movement or gravity.

The bending of hair cells within the maculae, caused by the movement of the gelatinous layer.

The stimulation of sensory receptors within the maculae due to hair cell deflection.

The state of the maculae when the body is standing still, with the utricle parallel to the ground and the saccule orthogonal.

The sensory structure responsible for detecting linear acceleration in vertical directions.

The sensory structure responsible for detecting linear acceleration in horizontal directions.

A type of receptor that is constantly stimulated, providing a steady stream of information to the brain.

The inner ear houses two distinct parts: the cochlea, responsible for hearing, and the labyrinth, dedicated to maintaining balance and spatial awareness.

The utricle and saccule are specialized sensory organs for detecting linear acceleration and head position relative to gravity. Imagine them as tiny gravity sensors.

The three semicircular canals are positioned perpendicular to each other (superior, posterior, lateral), allowing them to detect rotations in any plane of movement. Imagine them like tiny gyroscopes.

The vestibular system integrates with proprioception from the neck to determine if the head is moving independently or together with the body. It's like having two separate GPS systems working together.

The vestibular system works like a sophisticated 'inertial guidance system,' constantly monitoring the head's position and movement in space to maintain balance, stabilize vision, and perceive our environment.