A&P: Hearing and Equilibrium

Tympanic cavity

Air-filled space in the temporal bone

Opening in the inner ear; stapes held there by ligaments

Auditory ossicles

Three small bones that make up the eardrum

Incus

Anvil

Malleus

Hammer

Stapes

Stirrup

Eustachian tube

Connects middle ear to throat; maintains equal air pressure on both sides of eardrum

Auricle

Funnel-like structure; pinnacle

Osseous labyrinth

A bony canal in the temporal bone; contains a fluid called perilymph

Perilymph

Fluid contained within the osseous labyrinth

Membranous labyrinth

A tube that lies within the osseous labyrinth; contains a fluid called endolymph

Endolymph

Fluid contained within the membranous labyrinth

Cochlea

Functions in hearing; “snail shell”; contains the Organ of Corti

Organ of Corti

Contains hearing receptors and is located on the upper surface of the basilar membrane

Static Equilibrium

These organs sense and maintain position of the head when motionless

Dynamic equilibrium

Equilibrium of motion

Semicircular canals

Lie at right angles to each other and aid in balancing the head and body when they are moved suddenly

Tinnitus

Also called head noise; ear ringing

Vertigo

A whirling sensation; usually due to increased fluid pressure in the inner ear

Macula

Tiny structure on the anterior wall of the utricle; contains numerous hair cells that serve as sensory receptors