Structures and Functions of the Eye and Ear

Vocabulary review covering the key anatomical structures and their specific physiological functions for both the human eye and human ear.

Blind Spot

The area where the optic nerve leaves the eye; contains no receptor cells, and the brain fills in the missing information.

Optic Nerve

Structure that carries visual stimulus to the visual cortex of the brain.

Fovea

Known as "FoFo," this is the point of central focus in the eye.

Retina

Tissue that lines the back inner surface of the eye, containing 130 million photoreceptor cells (rods and cones).

Cornea

Protective covering that bends light to help with focus ("accommodation").

Lens

A biconcave structure located behind the iris that focuses light onto the retina.

Pupil

The opening that dilates and constricts to control the amount of light entering the eye.

Iris

The colored muscular part of the eye that controls the size of the pupil.

Auditory Canal

Canal that directs sound waves to the eardrum and traps debris.

Eardrum

Membrane of the middle ear that vibrates in response to sound waves and transfers vibrations to the malleus.

Stapes (Stirrup)

Transfers vibration from the incus to the oval window and then to fluid in the cochlea.

Auditory Nerve

Transmits impulses for hearing and balance to the thalamus, and then to auditory centers in the temporal lobe.

Cochlea

A snail-shaped tube filled with fluid and ~16,000 hair cells that bend with vibrations, stimulating the basilar membrane to nerve fibers to the auditory nerve.

Semicircular Canals

Three fluid-filled tubes that help maintain balance (vestibular).

Incus (Anvil)

Transfers vibrations from the malleus to the stapes.

Malleus (Hammer)

Transfers vibrations from the eardrum to the incus.

Pinna (Auricle)

The external part of the ear that funnels sound into the auditory canal.