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145 terms

Chapter 17: Sense Organs: The Eye and the Ear

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accommodation
Normal adjustment of the eye to focus on objects from far to near.
anterior chamber
Area behind the cornea and 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.
humor
Any body fluid, including blood and lymph
biconvex
Consisting of two surfaces that are rounded, elevated, and curved evenly, like part of a sphere. The lens of the eye is a biconvex body.
choroid
Middle, vascular layer of the eye, between the retina and the sclera.
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. Cones are responsible for color and central vision.
conjunctiva
Delicate membrane lining the undersurface of the eyelids and covering the anterior eyeball.
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 layer that opens and closes to allow more or less light into the eye. The central opening of the iris is the pupil.
lens
Transparent, biconvex body behind the pupil of the eye. It bends (refracts) 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 (chiasm means crossing).
optic disc
Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive 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 the thalamus 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.
aque/o
water
blephar/o
eyelid
conjunctiv/o
conjunctiva
cor/o
pupil
corne/o
cornea
cycl/o
ciliary body or muscle of the eye
dacry/o
tears, tear duct
ir/o
iris
irid/o
iris
kerat/o
cornea
lacrim/o
tears
ocul/o
eye
ophthalm/o
eye
opt/o
eye, vision
optic/o
eye, vision
palpebr/o
eyelid
papill/o
optic disc; nipple-like
phac/o
lens of the eye
phak/o
lens of the eye
pupill/o
pupil
retin/o
retina
scler/o
sclera; hard
uve/o
uvea; vascular layer of the eye
vitre/o
glassy
ambly/o
dull, dim
dipl/o
double
glauc/o
gray
mi/o
smaller, less
mydr/o
widen, enlarge
nyct/o
night
phot/o
light
presby/o
old age
scot/o
darkness
xer/o
dry
-opia
vision
-opsia
vision
-tropia
to turn
astigmatism
Defective curvature of the cornea or lens of the eye.
hyperopia (hypermetropia)
Farsightedness
myopia
Nearsightedness
presbyopia
Impairment of vision as a result of old age.
cataract
Clouding of the lens, causing decreased vision.
chalazion
Small, hard, cystic mass on the eyelid
diabetic retinopathy
Retinal effects of diabetes mellitus include microaneurysms, hemorrhages, dilation of retinal veins, and neovascularization (new blood vessels form in the retina).
glaucoma
Increased intraocular pressure results in damage to the retina and optic nerve with loss of vision.
hordeolum (stye or sty)
Localized, purulent, inflammatory staphylococcal infection of a sebaceous gland in the eyelid.
macular degeneration
Progressive damage to the macula of the retina
nystagmus
Repetitive rhythmic movements of one or both eyes.
blepharitis
Inflammation of the eyelid, causing redness, crusting, and swelling along lid margins.
dacryocystitis
Blockage, inflammation, and infection of a nasolacrimal duct and lacrimal sac, causing redness and swelling in the region between the nose and the lower lid.
ectropion
Outward sagging and eversion of the eyelid, leading to improper lacrimation and corneal drying and ulceration.
entropion
Inversion of the eyelid, causing the lashes to rub against the eye; corneal abrasion may result.
ptosis
Drooping of upper lid margin as a result of neuromuscular problems or trauma
xanthelasma
Raised yellowish plaque on eyelid caused by lipid disorder
retinal detachment
Two layers of the retina separate from each other.
strabismus
Abnormal deviation of the eye
fluorescein angiography
Intravenous injection of fluorescein (a dye) followed by serial photographs of the retina through dilated pupils.
ophthalmoscopy
Visual examination of the interior of the eye
slit lamp microscopy
Examination of anterior ocular structures under microscopic magnification
visual acuity test
Clarity of vision is assessed
visual field test
Measurement of the area (peripheral and central) within which objects are seen when the eyes are fixed, looking straight ahead without movement of the head.
enucleation
Removal of the entire eyeball
keratoplasty
Surgical repair of the cornea
laser photocoagulation
Intense, precisely focused light beam (argon laser) creates an inflammatory reaction that seals retinal tears and leaky retinal blood vessels.
LASIK
Use of an excimer laser to correct errors of refraction (myopia, hyperopia, and astigmatism). LASIK is an acronym for LASer In situ Keratomileusis.
phacoemulsification
Ultrasonic vibrations break up the lens, which then is aspirated through the ultrasonic probe.
scleral buckle
Suture of a silicone band to the sclera over a detached portion of the retina.
vitrectomy
Removal of the vitreous humor.
auditory canal
Channel that leads from the pinna to the eardrum.
auditory meatus
Auditory canal
auditory nerve fibers
Carry impulses from the inner ear to the brain (cerebral cortex). These fibers 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-sensitive receptor cells.
endolymph
Fluid within the labyrinth of the inner ear
eustachian tube
Auditory tube
incus
Second ossicle (bone) of the middle ear; incus 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; malleus 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. Stapes means stirrup.
tympanic membrane
Membrane between the outer and middle ear; also called the eardrum
vestibule
Central cavity of the labyrinth, connecting the semicircular canals and the cochlea. The vestibule contains two structures, the saccule and utricle, that help to maintain equilibrium.
acous/o
hearing
audi/o
hearing; the sense of hearing
audit/o
hearing
aur/o
ear
auricul/o
ear
cochle/o
cochlea
mastoid/o
mastoid process
myring/o
eardrum, tympanic membrane
ossicul/o
ossicle
ot/o
ear
salping/o
eustachian tube, auditory tube
staped/o
stapes
tympan/o
eardrum, tympanic membrane
vestibul/o
vestibule
-acusis
hearing
-cusis
hearing
-meter
instrument to measure
-otia
ear condition
acoustic neuroma
Benign tumor arising from the acoustic vestibulocochlear nerve (eighth cranial nerve) in the brain.
cholesteatoma
Collection of skin cells and cholesterol in a sac within the middle ear.
deafness
Loss of the ability to hear.
Meniere disease
Disorder of the labyrinth of the inner ear; elevated endolymph pressure within the cochlea and semicircular canals.
otitis media
Inflammation of the middle ear.
otosclerosis
Hardening of the bony tissue of the middle ear.
tinnitus
Sensation of noises (ringing, buzzing, whistling, booming) in the ears.
vertigo
Sensation of irregular or whirling motion either of oneself or of external objects.
audiometry
Testing of the sense of hearing.
cochlear implant procedure
Surgical insertion of a device that allows sensorineural hearing-impaired persons to understand speech
ear thermometry
Measurement of the temperature of the tympanic membrane by detection of infrared radiation from the eardrum.
otoscopy
Visual examination of the ear canal with an otoscope.
tuning fork test
Test of ear conduction using a vibration source (tuning fork)