Eyes 1 Flashcards
sensation
process of receiving, converting, and transmitting raw sensory information from the external and internal environments to the brain
perception
process of selecting, organizing, and interpreting sensory information
function of eye
capture light waves and focus them on receptors on the back of the eyeball
light is a type of
energy is proportional to
electromagnetic radiation
frequency or wavelength
high frequency
(short wavelength): Gamma radiation and cool colors - high energy
low frequency
(long wavelength): Radio waves and hot colors - low energy
wavelength
determines color, hue (inversely related to frequency)
frequency
determines color, hue (inversely related to wavelength)
amplitude
determines brightness, intensity
optics
Study of light rays and their interactions
reflection
Bouncing of light rays off a surface
absorption
Transfer of light energy to a particle or surface
refraction
Bending of light rays from one medium to another due to change in the speed of the light ray
conjunctiva
thin membrane that folds back from the inside of the eyelids, attaches to the sclera, and covers the cornea, vascularized
extraocular muscles
control movement of eye
Cornea –
transparent external surface over pupil; continuous with sclera, refracts incoming light rays
Sclera –
white tough outer coating on eyeball
Iris –
pigmented area; muscles that varies pupil size; inner circular muscles constrict pupil, outer radial muscles dilate pupil pattern unique to each individual, developed in the womb
Pupil –
opening through which light enters eye
retina
back of eye; layers of sensory cells and receptors where visual information captured to be transmitted to brain
macula lutea
middle area of retina for central vision, mostly cones but some rods, “spot”
fovea centralis
center of macula where image is focused on back of eye; retina is thin here and only contains cones, “pit”
optic nerve
retinal axons converge and leave the eye
optic disk
where optic nerve fibers exit the eye therefore no sensory cells and creates “blind spot”
“blind spot” where axons leave eye
*No photoreceptors here – brain constantly fills in for them
choroid
layer beneath retina with blood vessels to nourish cells of retina and melanin to absorb light so light won’t bounce around inside posterior chamber
tapetum lucidum
area of choroid where melanin is absent and replaced with reflective tissue so that light can be collected and reflected in a controlled manner in the posterior chamber, causing good night vision
ciliary body
composed of muscles which change the shape of the lens, secretes aqueous humor
ora serrata
serrated junction between the retina and the ciliary body
lens
stretched and contracted to focus on nearby and far away objects
zone fibers
(zonules) suspensory ligaments that attach the lens to the ciliary body
aqueous humor
watery fluid in anterior chamber between cornea and iris and posterior chamber between the iris and lens that nourishes the cornea and lens; produced by ciliary body, flows around iris, and exits through canals at the cornea sclera junction that drain to veins in the orbit
vitreous humor
jelly-like fluid in vitreous chamber behind lens; keeps eyeball round and keeps retina flat against back of eye
