Eyes & Ears

Cornea

As light enters the eye, it first passes through a lubricating tear film that coats the cornea. The clear cornea covers the front of the eye and helps to focus incoming light.

Aqueous humor

After light passes through the cornea it travels through a clear, watery fluid called the aqueous humor. The aqueous humor circulates throughout the front part of the eye, maintaining a constant pressure inside the eye.

pupil

the contractile aperture in the center of the iris of the eye; resembles a large black dot

lens

After light travels through the pupil, it must pass through the lens. The human lens, much like the lens of a camera, is responsible for focusing light. The lens can change its shape to focus on nearby and distant objects.

vitreous humor

After being focused by the lens, light passes through the center of the eye on its way to the retina. The eye is filled with a clear, jelly-like substance called the vitreous.

fovea

At the very center of the macula is the site of our sharpest vision.

optic nerve

The optic nerve is a bundle of nerve fibers which carries visual information from the eye to the brain.

optic chiasma

the crossing of the optic nerves from the two eyes at the base of the brain

visual cortex

he cortical area that receives information from the lateral geniculate body of the thalamus

Blind spot

visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc of the retina where the optic nerve passes through it.

Ciliary muscle

a smooth muscle in the eye that controls the eye's accommodation for viewing objects at varying distances and regulates the flow of aqueous humour through Schlemm's canal.

Choroid

Behind the retina, a layer of blood vessels called the choroid supplies oxygen and nutrients to the outer layers of the retina

Iris

The iris is the colored part of the eye. As light conditions change, the iris may dilate to make the pupil bigger or constrict to make the pupil smaller. This allows more or less light into the eye.

Ligaments (zonule fibers)

suspends the lens attached to the anterior portion of the ciliary body

Retina

The retina is a thin, light-sensitive tissue lining the back of the eye that acts much like film in a camera. Light must be properly focused onto the retina, and the surface of the retina must be flat, smooth, and in good working order to produce a clear

Sclera

The white part of the eye is called the sclera. The sclera is composed of tough, fibrous tissue that protects the inner workings of the eye.

Macula

The center, or bull's eye of the retina is called the macula. The macula contains a high concentration of photoreceptor cells which convert light into nerve signals. Because of the high concentration of photoreceptors, we are able to see fine details such

ophthamologist

treats diseases of the eye and performs surgery

optometrist

examines eyes, writes prescriptions to correct vision

optician

grinds lenses and fits eyeglass frames

opthalmoscope

device used to examine the back of the eyeball

otolaryngology

treats diseases of the ear, nose, & throat

Depth perception

the ability to see three dimensions

Rod cells

photoreceptors that respond to light

Cone cells

help distinguish between colors

Lacrimal glands

help with crying

Tear Ducts

damage to them induce crying, tearing continuously, etc.

Pinna (auricle)

the externally visible cartilaginous structure of the external ear

Auditory canal

a tube running from the outer ear to the middle ear, extends from the pinna to the eardrum

Tympanum

thin membrane that separates the external ear from the middle ear

Malleus (hammer)

the ossicle attached to the eardrum

Incus (anvil)

anvil-shaped small bone or ossicle in the middle ear that connects the malleus to the stapes

Stapes (stirrup)

the stirrup-shaped ossicle that transmits sound from the incus to the cochlea

Oval window

a membrane-covered opening which leads from the middle ear to the vestibule of the inner ear

Cochlea

the auditory portion of the inner ear. Its core component is the Organ of Corti, the sensory organ of hearing

Hair cells

the sensory receptors of both the auditory system and the vestibular system

Auditory nerve

a nerve in the head that carries signals from the cochlea of the inner ear to the brain

Auditory cortex

the region of the brain that is responsible for processing of auditory (sound) information