7.7 Special Senses Key Terms
A clear, watery fluid that fills the space between the cornea and iris; it helps maintain the forward curvature of the eyeball and refracts light rays.
aqueous humor
A mucous membrane that lines the eyelids and covers the front of the eye to provide additional protection and lubrication.
conjunctiva
Composed of delicate, hairlike mechanoreceptor cells (located in the cochlea), it transmits the impulse from sound waves to the auditory nerve.
organ of Corti
The innermost layer of the eye, made of nerve cells that transmit light impulses to the optic nerve.
retina
Glands in the eye that produce tears, which constantly moisten and cleanse the eye.
lacrimal glands:
A canal, or tube (also called the external auditory meatus), that sound waves travel through to reach the eardrum.
auditory canal
The circular, transparent part of the front of the sclera that allows light rays to enter the eye.
cornea
Three small bones in the middle ear (malleus, incus, and stapes) that transmit sound waves from the tympanic membrane to the inner ear.
ossicles
The outermost, tough connective tissue layer of the eye (the "white" of the eye) that maintains the eye's shape.
sclera
The innermost layer of the eye, made of nerve cells that transmit light impulses to the optic nerve.
retina
The visible part of the outer ear; also called the pinna.
auricle
A tube that connects the middle ear to the pharynx (throat) and helps equalize air pressure on both sides of the tympanic membrane.
eustachian tube
The visible part of the outer ear; also called the auricle.
pinna
Canals in the inner ear containing liquid and hairlike cells that send impulses to the cerebellum to help maintain balance and equilibrium.
semicircular canals
The middle layer of the eye, which is interlaced with many blood vessels that nourish the eyes.
choroid coat
The colored portion of the eye, located behind the cornea.
iris
The opening in the center of the iris; muscles control its size to regulate the amount of light entering the eye.
pupil
The eardrum; it separates the outer ear from the middle ear and vibrates when sound waves hit it.
tympanic membrane
A structure in the inner ear shaped like a snail’s shell that contains the organ of Corti.
cochlea
A circular structure located behind the pupil and suspended by ligaments; it refracts (bends) light rays to focus them on the retina.
lens
To bend light rays.
refracts
The jellylike substance that fills the area behind the lens, helping to maintain the shape of the eyeball and refract light rays.
vitreous humor