AP Psych Unit 1 - Eye/Ear Parts

Cornea

The eye’s clear, protective outer layer, covering the pupil and iris. Also bends light to help provide focus.

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

Lens

The transparent structure behind the pupil that changes shape to help focus light rays into images on the retina - accomodation

Accomodation

The process by which the eye’s lens changes shape to focus images of near or far objects on the retina

Retina

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

• Rods: retinal receptors that detect black, white, and gray, and are sensitive to movement; necessary for peripheral and twilight vision

• Cones: retinal recpetors that detect fine detail and give rise to color sensations; are concentrated near the center of the retina and function in daylight/well-lit conditions

Optic Nerve

The nerve that carries neural impluses from the eye to the brain

Blind Spot

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

Fovea

The central focus point in the retina, around which the eye’s cones cluster

Middle Ear

The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and 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 thorugh the cochlear fluid trigger nerve impulses

Inner Ear

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

Auditory 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

The Bones of the Middle Ear/Ossicles

Hammer (Malleus), Anvil (Incus), & Stirrup (Stapes)

→ 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

Auditory Nerve

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