Lacrimal glands
Produce tears for the eyes.
Conjunctiva
Mucous membrane that lines the eyelids and covers the front of the eye.
Sclera
The "white" of the eye; outermost layer of the eye; gives the eye its shape.
Cornea
Circular, transparent part of the front of the sclera. Allows light rays to enter the eye.
Choroid coat
Middle layer of the eye;interlaced with blood vessels that nourish the eye.
Retina
Innermost layer of the eye;transmits the light impulses to the optic nerve.
Cones
Used mainly for vision when it is light; special cell in the retina.
Rods
Special cells on the retina used for dark or dim vision.
Fovea Centralis
Depression located on the back surface of the retina; houses most of the cones.
Iris
Colored portion of the eye;located behind the cornea; contains the muscles that control the size of the pupil.
Pupil
Opening in the center of the iris.
Lens
Circular structure located behind the pupil and suspended in position by ligaments.
Aqueous humor
Clear, watery fluid that fills the space between the cornea and iris. Helps maintain the forward curvature of the eyeball and refracts light rays.
Vireous Humor
Jellylike substance that fills the area behind the lens. It helps maintain the shape of the eyeball and also refracts light rays.
Amblyopia
Also known as a"lazy eye".
Astigmatism
An abnormal shape or curvature of the cornea that cuases blurred vision.
Cataract
Lens becomes cloudy.
Conjunctivitis
Inflammation of the conjunctivia; contagious; usually caused by a bacteria or virus; commonly called "pink eye".
Glaucoma
Increased introccular pressure caused by an excess amount of aqueous humor.
Hyperopia
Farsightedness; occurs when the light rays are not refracted sharply enough, and the image focuses behind the retina.
Myopia
Nearsightedness; occurs when the light rays are refracted too sharply and the image focuses in front of the retina.
Presbyopia
Farsightedness caused by a loss of lens elasticity. Normal aging process.
Strabismus
When the eyes do not move together; eyes move inward or outward or up or down; caused by muscle weakness.
Pinna
Visible part of the ear.
Auditory Canal
Canal that leads to the internal structures of the ear.
Cerumen
Wax in the ear that protects the ear.
Tympanic membrane
Separates the outer ear from the middle ear. It vibrates when sound waves hit it and transmits the sound waves to the middle ear
Malleus / Incus / Stapes
Bones in the ear that are connected and transmit sound waves from the typmpanic membrane to the inner ear.
Eustachian tube
Tube that allows air to enter the middle ear and helps equalize air pressure on both sids of the tympanic membrane.
Vestibule
Acts as the entrance to the two other parts of the inner ear.
Cochlea
Shaped like a snail's shell;contains the Organ of Corti.
Organ of Corti
Receptor of sound waves; transmits impulses from sound waves to the auditory nerve.
Semicircular canal
Responsible for transmiting impulses to the cerebellum of the brain to help maintain our sense of balance and equilibrium.
Conductive Hearing Loss
Occurs when sound waves are not conducted to the inner ear.
Sensory Hearing Loss
Occurs when there is damage to the inner ear or auditory nerve.
Meniere's Disease
Collection of fluid in the inner ear and degereration of the hair cells in the cochlea and vestibule.
Otitis Externa
Inflammation of the external auditory canal; "Swimmer's ear"; caused by a pathogenic bacteria.
Otitis Media
Inflammation or infection of the middle ear and is caused by a bateria or virus.
Myringotomy
Incision of the tympanic membrane.
Otosclerosis
Stapes becomes immobile, causes conductive hearing loss.