Ch. 7.7 Special Senses Key Terms
A clear, watery fluid filling the space between the cornea and iris. It helps maintain the eyeball's forward curve and refracts light.
auditory canal
(or external auditory meatus): The canal, or tube, that the pinna leads to. Sound waves travel through it to reach the eardrum.
auricle/pinna
The visible part of the ear, made of elastic cartilage covered by skin.
choroid coat
The middle layer of the eye, which contains many blood vessels that nourish the eyes.
cochlea
The snail-shaped part of the inner ear that contains the organ of Corti.
conjunctiva
A mucous membrane that lines the eyelids and covers the front of the eye to provide protection and lubrication.
cornea
The circular, transparent part of the front of the sclera that allows light rays to enter the eye.
eustachian tube
A tube that connects the middle ear to the pharynx (throat). It allows air to enter the middle ear to equalize pressure on both sides of the eardrum.
iris
The colored portion of the eye located behind the cornea. It contains muscles that control the size of the pupil to regulate the amount of light entering.
lacrimal glands
Glands in the eye that produce tears to constantly moisten and cleanse the eye.
lens
A circular structure behind the pupil that refracts (bends) light rays to focus them on the retina.
organ of corti
A receptor of sound waves located in the cochlea. It contains delicate, hairlike cells that transmit sound impulses to the auditory nerve.
Three small bones in the middle ear (malleus, incus, and stapes) that are connected and transmit sound waves from the eardrum to the inner ear.
pinna/auricles
The visible part of the ear, made of elastic cartilage covered by skin.
pupil
The opening in the center of the iris.
refracts
To bend light rays. This is done by the cornea, aqueous humor, lens, and vitreous humor so that rays focus on the retina.
Retina
The innermost layer of the eye, made of many nerve cells (like rods and cones) that transmit light impulses to the optic nerve.
sclera
The tough, connective tissue outer layer, often called the "white" of the eye. It maintains the shape of the eye.
semicircular canals
Canals in the inner ear that contain liquid and hairlike cells. Impulses sent from them to the cerebellum help maintain balance and equilibrium.
tympanic membrane (eardrum)
The membrane that separates the outer ear from the middle ear. It vibrates when sound waves hit it, transmitting them to the middle ear.
vestibule
The first section of the inner ear, which acts as the entrance to the cochlea and semicircular canals.
vitreous humor
The jellylike substance filling the area behind the lens. It helps maintain the eyeball's shape and also refracts light rays.