17. Special Senses Flashcards
accommodation
- normal adjustment of the eye to focus on objects from far to near
- 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 and in front of the lens and iris
- contains aqueous humor
aqueous humor
- fluid produced by the ciliary body and found in the anterior chamber
- humor is any body fluid (blood and lymph)
biconvex
- consisting of two surfaces that are rounded, elevated, and curved evenly, like part of a sphere
- lens of the eye is a biconvex body
choroid
-middle, vacular layer of the eye, between the retina and the sclera
ciliary body
- structure on each side of the lens that connects the choroid and iris
- 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
- responsible for color and central vision
conjunctiva
-delicate membrane lining the eyelids and covering the 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
- visualized with an opthalmoscope
iris
- pigmented (colored) layer that opens and closes to allow more or less light into the eye
- central opening of the iris is the pupil
lens
- transparent, biconvex body behind the pupil of the eye
- 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
- contain 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
- 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
- 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
re-
back
-fract
break
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 low 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 lends in the vitreous chamber
- helps maintain the shape of the eyeball
aque/o
water
blephar/o
eyelid
conjuctiv/o
conjuctiva
cor/o
pupil
corne/o
cornea
cycl/o
ciliary body or muscle of the ye
dacry/o
tears, tear duct
ir/o, irid/o
iris
-colored portion of the eye
kerat/o
cornea
lacrim/o
tears
ocul/o
eye
ophthalm/o
eye
opt/o, optic/o
eye, vision
palpebr/o
eyelid
papill/o
optic disc; nipple like
phac/o, phak/o
lens of the eye
pupill/o
pupil
retin/o
retina
scler/o
sclera (white of the eye); hard
uve/o
uvea; vascular layer of the eye (iris, ciliary body, and choroid
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
astrigmatism
defective curvature of the cornea or lens of the eye
-light rays unevenly focused on the retina
hyperopia
- farsightedness
- importer focus behind retina
- biconvex
myopia
- nearsightedness
- improper focus in front of retina
- biconcave
presbyopia
-impairment of vision as a result of old age
cataract
-clouding of the lens, causing decreased vision
chalazion
- small, hard cystic mass (granuloma) on the eyelid
- chronic inflammation of a sebaceous gland
diabetic retinopathy
-retinal effects of diabetes mellitus include microaneurysms, hemorrhages, dilation of retinal veins, and neovascularization (new blood vessels from in the retina)
glaucoma
- increased intraocular pressure results in damage to the retina and optic nerve with loss of vision
- inability to drain aqueous humor from eye
hordeolum
- localized, purulent, inflammatory staphylococcal infection of a sebaceous oil-producing gland in the eyelid
- stye
macular degeneration
- progressive damage to the macula of the retina
- causes blindness
nystagmus
- repetitive rhythmic movement of one or both eyes
- normal in newborns
- can be caused by brain tumor or disease of inner ear
retinal detachment
- two layer of the retina separate from each other
- trauma to the eye, injury can cause
strabismus
- abnormal deviation of the eye
- failure of eyes to look in same direction
- due to weakness of eye muscle
trabecul/o
small beam, rod, plank of wood
blepharitis
-inflammation of eyelid, causing redness, crusting, and swelling along lid margins
chalazion
-granuloma formed around an inflamed sebaceous gland
dacryocystitis
- blockage, inflammation and infection of a nasolacrimal duct and lacrimal sac
- casues 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 ulceration
entropion
inversion of the eyelid, causing the lashes to rub against the eye
-corneal abrasion may result
hordeolum (stye)
-small, superficial white nodule along lid margin due to infection of a sebaceous gland
ptosis
drooping of upper lid margin from neuromuscular problems or trauma
xanthelasma
raised yellowish plaque on eyelid caused by lipid disorder
fluorescein angiography
- Intravenous injection of fluorescein (a dye) followed by serial photographs of the retina through dilated pupils.
- diagnostic about blood flow in the retina
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
- snellen chart
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, astigmatism)
phacoemulsification
- ultrasonic vibrations break up the lens; the pieces are then aspirated through the ultrasonic probe
- typical surgery for cataract removal
scleral buckle
-suture of a silicone band to the sclera over a detached portion of the retina
vitrectomy
- removal of the vitreous humor
- necessary when blood and scare tissue accumulate
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)
- compose the vestibulocohlear nerve
auditory tube
- channel between the middle ear and the nasopharynx
- eustachian tube
auricle
- flap of the ear
- protruding part of the external ear
- pinna
cerumen
waxy substance secreted by the external ear
-earwax
cochlea
snail shell 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 (small bone) of the middle ear
- anvil
labyrinth
maze-like series of canals of th einner ear
-includes cochlea, vestibule, semicircular canals
malleus
- first ossicle of the middle ear
- hammer
organ of corti
-sensitive auditory receptor area found in the cochlea of the inner ear
ossicle
small bone of the ear
-includes malleus, incus, 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 ear
semicircular canal
passages in the inner ear associated with maintaining equilibrium
stapes
- third ossicle of the middle ear
- stirrup
tympanic membrane
- membrane between the outer and the middle ear
- eardrum
vestibule
- central cavity of the labyrinth
- connecting the semicircular canals and the cochlea
- contains two structures: saccule and utricle
- helps maintain equilibrium
acous/o
hearing
audit/o
hearing
aur/o, 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, or -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 withing the cochlea (cochlear hydrops) and semicircular canals (vestibular hydrops)
otitis media
-inflammation of the middle ear
otosclerosis
hardening of the bony tissue of the middle ear
tinnitus
sensation of noises (ringing, buzzing, whistling, boom) in the ear
vertigo
sensation of irregular or whirling motion either of oneself or of external objects
audiometry
-testing 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)
- rinne test
- weber test