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Language of Medicine Chapter 17- Keywords

Terms in this set (47)

accomodation
normal adjustment of the eye to focus on objects from far to near. The ciliary body adjusts the lens (rounding it) and the pupil constricts. When the eye focuses from near to far, the ciliary body flattens the lens and the pupil dilates.
anterior chamber
area behind the cornea & in front of the lens and iris. It contains aqueous humor.
aqueous humor
fluid produced by the ciliary body and found in the anterior chamber
biconvex
consisting of two surfaces that are rounded, elevated, and curved evenly, like part of a sphere.
choroid
middle vascular layer of the eye, between the retina and sclera; a dark brown membrane that contains many blood vessels
ciliary body
Structure surrounding the lens that connects the choroid and iris. It contains ciliary muscles, which control the shape of the lens, and it secretes aqueous humor.
cone
Photoreceptor cell in the retina that transforms light energy into a nerve impulse. These are responsible for color and central vision.
cornea
Fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball.
fovea centralis
tiny pit or depression in the retina that is the region of clearest vision
fundus of the eye
Posterior, inner part of the eye.
iris
Pigmented (colored) layer that opens and closes to allow more or less light in the eye. The central opening of this is the pupil.
lens
transparent bioconvex structure behind the pupil of the eye. It bends light rays to bring them into focus on the retina
macula
yellowish region on the retina lateral to and slightly below the optic disc; contains the fovea centralis, which is the area of clearest vision.
optic chiasm
Point at which optic nerve fibers cross in the brain.
optic disc
Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of eye because it contains only nerve fibers, no rods or cones, and is thus insenseitive to light.
optic nerve
cranial nerve carrying impulses from the retina to the brain (cerebral cortex)
pupil
central opening of the eye, surrounded by the iris, through which light rays pass. It appears dark.
refraction
Bending of light rays by the cornea, lens, and fluids of the eye to bring the rays into focus on the retina.
retina
light sensitive nerve cell layer of the eye containing photoreceptor cells (rods and cones)
rod
photoreceptor cell of the retina essential for vision in dim light and for peripheral vision
sclera
Tough, white outer coat of the eyeball
thalamus
Relay center of the brain. Optic nerve fibers pass through this on their way to the cerebral cortex .
vitreous humor
soft, jelly-like material behind the lens in the vitreous chamber; helps maintain the shape of the eyeball
Auditory Canal
Channel that leads from the pinnna to the eardrum; external auditory meatus
Auditory Meatus
Auditory canal
Auditory nerve fibers
Carry impulses from the inner ear to the brain (cerebral cortex). These compose the vestibulocochlear nerve (cranial nerve VIII).
Auditory tube
Channel between the middle ear and the nasopharynx (eustachian tube)
Auricle
Flap of the ear; the protruding part of the external ear or pinna
Cerumen
Waxy substance secreted by the external ear also called earwax
Cochlea
Snail-shaped, spirally wound tube in the inner ear; contains hearing receptor cells
Endolymph
Fluid with the labyrinth of the inner ear
Eustachian tube
A canal leading from the middle ear to the pharynx. Auditory tube
incus
Second ossicle (bone) of the middle ear; means anvil
labyrinth
maze-like series of canals of the inner ear.This includes the cochlea, vestibule, and semicircular canals
malleus
first ossicle of the middle ear; this means hammer
organ of Corti
sensitive auditory receptor area found in the cochlea of the inner ear
ossicle
small bone of the ear; includes the malleus, incus and stapes
oval window
membrane between the middle ear and the inner ear
perilymph
fluid contained in the labyrinth of the inner ear
pinna
auricle; flap of the ear
semicircular canals
passages in the inner ear associated with maintaining equilibrium
stapes
third ossicle of the middle ear; this means stirrup
tympanic membrane
membrane between the outer and the middle ear; also called the eardrum
vestibule
central cavity of the labyrinth, connecting the semicircular canals and the cochlea. Contains two structures; the saccule and utricle, that help maintain equilibrium.
uvea
The choroid, iris, and ciliary body of the eye
conjunctiva
A membrane lining the inner surfaces of the eyelids and anterior portion of the eyeball over the white of the eye.
vitreous chamber
A large region behind the lens filled with vitreous humor.
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