The ey Flashcards
Highest refractive index
from air to cornea
highest refractive indices
lens
Zonule fibers
suspends the lens (tightened causes lens to flatten, loosened causes lens to round)
iris
complex orientation of smooth muscle functioning as a sphincter
pupil
diaphragm-contsricts and opens in response to light
cornea
connective tissue
clear
first part of eye
importent for refraction
posterior chamber
small chamber behind iris and between ciliary muscle
ciliary muscle
continuous with muscle and connects to the choriod
Choroid
vascular layer
has nerves and blood vessels
between retina and sclera
retina
continuous with the optic nerve
sclera
dense, white connective tissue
-holds eye together
fovea
dip in the retina
-highest density of cones
-“packed cones”
optic disc
the place in the retina that leads to the optic nerve & retinal vessels that transmits to the brain
Distant vision is aka
unaccomodated
flattened lens, tighetened
Near vision aka
accomodated
more convex lens, zonule fibers loosen
blurry image is a result of
lens + retina don’t line up
ciliary muscles contracted causes
- ligaments slackened
- lens rounded
Ciliary muscles relaxed causes
- lens flattened
- ligaments pulled tight
lens flexibility decreases with
age
5 types of retinal neruons
- photoreceptors
- bipolar cells
- ganglion cells
- horizontal cells
- amicrin cells
photoreceptors
rod/cones
transduce light into electrical signals
Bipolar cells
axon–dendrite
target of NT release from photoreceptors
sends signal to ganglion cells
Ganglion cells
- receives signals from bipolars
- axon coalesce to form optic nerve
- 1st cell in retina to generate action potential
Horizontal Cells
form photoreceptors
synapse within bipolars
Amicrin cells
form synapses between bipolar & ganglion cells
OR
rrelay signals between bipolar & ganglion cells (peripheral retina)
magnitude is proportional to
stimulus (graded potentials)
order of layers within the retina (distal to proximal)
- pigment epithelium
- photoreceptor outer segements
3.
