Vision Quiz Flashcards
outermost; avascular layer of eye
fibrous layer
tough outer layer = white of the eye (reflects light) connective tissue that serves as a protective layer for the eye
sclera
anterior portion; transparent and function is to let light waves into the eye; allows light to enter the eye
cornea
middle layer of the eye and contains blood vessels
vascular layer
helps to nourish the inner layer of the eye through diffusion; beneath the eye
choroid
produces aqueous humor which needs to constantly be replaced containing the ciliary muscle
ciliary body
connected to the lens via the suspensory ligaments ; function is to change the shape of lens (used to focus the light on the retina)
ciliary muscle
a pigmented, donut of muscle giving color to the eye
iris
the hole of the iris
pupil
makes the pupil smaller
constrictor pupillae
makes the pupil larger
dilator pupillae
next to the choroid; contains melanin and functions to absorb light to prevent it from reflecting across the retina and blurring vision
retinal pigmented epithelium
comprised of three layers - inner layer of ganglion cells, middle layer of bipolar, amacrine, and horizontal cells, and outer layer of photoreceptors
neural layer
two types of photoreceptors
rods and cones
provide us with color vision in relatively bright light; sunlight during the day
cones
provide the ability to see in black and white during relatively low light conditions; moon at night
rods
indentation of the retina (only cones & has best visual acuity)
fovea
blind spot of retina (no photoreceptors)
optic disk
behind the lens; contains the vitreous humor
posterior cavity
a firm gelatinous mass which maintains the spherical structure of the eye
vitreous humor
in front of the lens; filled with aqueous humor
anterior cavity
from the cornea to the iris
anterior chamber
from the iris to the lens
posterior chamber
a form of energy existing as electromagnetic waves; can be reflected and refracted
light
they can be convex (cause light to converge at focal point) or concave (cause light to diverge)
lenses
the ability of the lens to change its shape in order to change the angle of refraction of a light ray in order to see something close up
accommodation
either the lens or the cornea is too bulged (strong) for the length of the eye so light rays bend too much
myopia (near-sightedness)
either the lens or the cornea is too weak for the length of the eye
hyperopia (far-sightedness)
irregularly shaped lens or cornea causing erratic refraction
astigmatism
hardening of the lens with age
presbyopia
the lens or cornea becomes opaque
cataract
increased bulge of the cornea due to the increase of aqueous humor
glaucoma
the conversion of light energy into electrical energy
phototransduction
formed from retinal and opsin
rhodopsin
when in dim light and looking in stacked disks in rods…
cGMP levels are high in the cell
when cGMP levels are high in the cell…
Na+ channels open
