Physiology of Vision Flashcards
the lens is suspended by _________ from __________
the lens is suspended by ZONULAR FIBERS from CILIARY MUSCLE
relaxed lens
- thick lens
- near vision
vitreous humor: location, consistency
- posterior chamber
- jelly like
aqueous humor: location, consistency
- anterior chamber
- serous (less jelly)
accommodation
- change the shape of the lens to focus near
- relax ciliary muscle to thicken lens
image created on back of retina
- inverted L to R
- inverted up/down
cones
- high acuity
- low sensitivity
- daytime
- color vision
- cone shaped
- concentrated in fovea
rods
- decreased acuity
- increased sensitivity
- nighttime
- black/white
- blunt tip
- more numerous than cones
- none in fovea
proteins on rods (and fxn)
OPSIN protein
- absorbs light
- changes NT released at each layer, which changes firing potential of ganglion cells
order the light hits the (main) cells
- ganglion (first)
- bipolar
- photoreceptors (last)
layers of the retina
- inner limiting membrane
- nerve fiber layer
- ganglion cells
- amacrine cells
- bipolar cells
- horizontal cells
- Muller cells
- outer limiting membrane
- rods/cones
- pigment epithelium
- choroid
choroid
- blood vessels
- supply outer 1/2 of retina
- deepest layer
inheritance of colorblindness
x-linked
-men more likely to be colorblind
optic disc
- where optic nerve exits
- blind spot
- ganglion leave
retinal artery supplies
-inner 2/3 of retina
fovea
- increased acuity
- daytime
- mostly cones
Light from the center of gaze, the fixation point, falls on this part of the retina.
macula lutea
- surrounds fovea
- specialized for high acuity daylight vision
- yellowish
the optic disc is ________ to fovea (medial/lateral)
the optic disc is LATERAL to fovea
temporal retina
- light from _________
- goes ________
temporal retina
- light from MEDIAL field
- goes IPSILATERALLY
nasal retina
- light from _________
- goes ________
nasal retina
- light from LATERAL field
- goes CONTRALATERALLY
information from right visual field projects to ________ side of the brain
information from right visual field projects to LEFT side of the brain
-info from left visual field projects to right side of brain
lesion of lower bank of calcarine fissure
- affects Meyers loop (inferior retinal fibers, superior visual field)
- contralateral superior quadrantanopia
- “pie in the sky” deficit
lesion of upper bank of calcarine fissure
-affects superior fibers of optic radiation
superior retina, inferior visual field
lateral geniculate nucleus
- Carries input from retina to primary visual cortex
- Involved in vision and visual recognition
Lesion:
- Visual agnosia
- Alexia without agraphia