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