Ch. 7.7 Special Senses Key Terms
Aqueous humor
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.
Cochlea
The inner ear structure shaped like a snail's shell. It contains delicate, hairlike mechanoreceptor cells, which compose the organ of Corti.
Lacrimal glands
Glands in the eye that produce tears, which constantly moisten and cleanse the eye.
Refracts
The action of bending light rays. The lens, cornea, aqueous humor, and vitreous humor all contribute to refracting light rays so they focus on the retina.
Vestibule
The first section of the inner ear, which acts as the entrance to the two other parts of the inner ear (cochlea and semicircular canals).
Auditory canal
A canal, or tube, that leads from the pinna/auricle to the tympanic membrane. It is also called the external auditory meatus.
Conjunctiva
A mucous membrane that lines the eyelids and covers the front of the eye to provide additional protection and lubrication.
Lens
A circular structure located behind the pupil and suspended in position by ligaments. It refracts (bends) light rays so the rays focus on the retina.
Retina
The innermost layer of the eye, made of many layers of nerve cells. These cells transmit the light impulses to the optic nerve.
Vitreous humor
The jellylike substance that fills the area behind the lens. It helps maintain the shape of the eyeball and also refracts light rays.
Organ of Corti
A receptor of sound waves, composed of delicate, hairlike mechanoreceptor cells located within the cochlea. It transmits the impulses from sound waves to the auditory nerve.
Cornea
A circular, transparent part of the front of the sclera. It allows light rays to enter the eye.
Ossicles
The three small bones in the middle ear (the malleus, the incus, and the stapes). They transmit sound waves from the tympanic membrane to the inner ear.
Sclera
The outermost layer of the eye, a tough connective tissue frequently referred to as the "white" of the eye. It maintains the shape of the eye.
Auricle
The visible part of the ear, also called the pinna. It is elastic cartilage covered by skin.
Eustachian tube
A tube that connects the middle ear to the pharynx (throat). It allows air to enter the middle ear and helps equalize air pressure on both sides of the tympanic membrane.
Pinna
The visible part of the ear, also called the auricle. It is elastic cartilage covered by skin.
Semicircular canals
Structures located in the inner ear that contain a liquid and delicate, hairlike cells. Impulses sent from these canals to the cerebellum of the brain help to maintain our sense of balance and equilibrium.
Choroid coat
The middle layer of the eye, which is interlaced with many blood vessels that nourish the eyes.
Iris
The colored portion of the eye. It is located behind the cornea on the front of the choroid coat.
Pupil
The opening in the center of the iris.
Tympanic membrane
The eardrum, which separates the outer ear from the middle ear. It vibrates when sound waves hit it and transmits the sound waves to the middle ear.