AP Psychology Eye & Ear Parts + Functions

Lens

the transparent structure behind the pupil that changes shape to help focus images on the retina.

Retina

the light-sensitive back inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.

Optic Nerve

the nerve that carries neural impulses from the eye to the brain.

Fovea

the central focal point in the retina, around which the eye’s cones cluster.

Blind Spot

the point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there.

Cornea

the eye’s clear, protective outer layer, covering the pupil and iris.

Pupil

the adjustable opening in the center of the eye through which light enters.

Iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.

Middle Ear

the chamber between the eardrum and cochlea containing three tiny bones (the ossicles: hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window.

Cochlea

a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses.

Inner Ear

the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

Semicircular Canals

detect rotational head movement and provide the sensory foundation for spatial orientation, balance, and motor control.con

Outer Ear

contains pinna and ear canal

Ear Canal

Narrow, tubelike passage in the outer ear, channeling sound waves to the eardrum.

Eardrum

Start of process of transforming sound energy into neural messages - sound waves strike this causing the membrane to vibrate.

Auditory Nerve

Carries neural messages to thalamus and to auditory cortex (temporal lobe)

Ossicles

Hammer (malleus), anvil (incus), and stirrup (Staples)

• amplify and relay eardrum’s vibrations through oval window into cochlea

Oval Window

Where the stirrup attaches; the cochlea’s membrane-covered opening

Basilar Membrane

Membrane of cochlea with protruding hair cells