hearing & equilibrium

What type of sensory information are hearing and equilibrium?

Somatic sensory information.

What type of cells are responsible for detecting hearing and equilibrium?

Hair cells, which are specialized receptor cells.

Where are hair cells located in the inner ear?

Maculae of the vestibule, ampullae of the semicircular ducts, and cochlea.

What type of receptors are hair cells?

Mechanoreceptors.

What structure is responsible for hearing?

The cochlea.

What causes the tympanic membrane to vibrate?

Incoming sound waves.

What happens when the tympanic membrane vibrates?

It causes the auditory ossicles to vibrate.

What is the order of the auditory ossicles?

Malleus → Incus → Stapes.

What structure does the stapes transmit vibrations to?

The oval window.

What happens when the stapes vibrates against the oval window?

It creates pressure waves in the perilymph.

What do different sound frequencies cause in the cochlea?

Different frequencies cause different-sized waves.

What do the pressure waves in the cochlea move against?

The vestibular or basilar membrane.

What happens when the basilar membrane moves?

It bends the stereocilia on the hair cells.

What happens when the stereocilia bend?

The bending stimulates the hair cells and causes nerve impulses to fire.

Which structures are responsible for equilibrium?

The vestibule and semicircular ducts.

What type of equilibrium does the vestibule detect?

Static equilibrium (head position).

What type of equilibrium do the semicircular ducts detect?

Dynamic equilibrium (changes in direction or acceleration).

What covers the hair cells in the vestibule?

A gelatinous membrane containing otoliths.

What happens when head position changes in the vestibule?

Gravity acts on the otoliths, causing the gelatinous membrane to move.

What happens when the gelatinous membrane moves in the vestibule?

It bends the cilia on the hair cells, causing nerve impulses to fire.

What specific changes do the semicircular ducts monitor during dynamic equilibrium?

Changes in direction and rotational acceleration.

What causes endolymph to move in the semicircular ducts?

Directional or rotational acceleration of the head.

What does moving endolymph push against in the semicircular ducts?

The gelatinous cupula covering the hair cells.

What happens when the gelatinous cupula bends in the semicircular ducts?

It bends the cilia on the hair cells, causing nerve impulses to fire.

What two sensory functions are classified as somatic sensory?

Hearing and equilibrium.

Hair cells

Specialized receptor cells that detect mechanical movement.

Which inner ear regions contain hair cells?

Maculae of the vestibule, ampullae of the semicircular ducts, and cochlea.

What functional class of receptors do hair cells belong to?

Mechanoreceptors.

What causes different-sized waves in the cochlea?

Different sound frequencies.

What happens when pressure waves reach the vestibular or basilar membrane?

They cause membrane movement, which bends the cilia on hair cells and triggers nerve impulses.

What covers the vestibular hair cells?

A gelatinous layer containing otoliths.

What causes the otoliths to move when head position changes?

Gravity acts on the otoliths, shifting the gelatinous layer.

What happens when the gelatinous layer moves over vestibular hair cells?

It bends their cilia, causing sensory neurons to fire.

What causes endolymph to flow in the semicircular ducts?

Directional and acceleration forces caused by head movement.

What covers the hair cells in the semicircular ducts?

A gelatinous structure called the cupula.

What happens when endolymph moves against the gelatinous cupula?

It bends the gelatinous structure, which bends the cilia on hair cells and triggers nerve impulses.