NEU211 Chapter 9 EXAM 3

vision

sense of light

light

electromagnetic radiation seen by eyes

wavelength

distance between peaks

frequency

number waves/sec

amplitude

intensity of wave

high energy = ___ freq and ___ pitch

high, high

as freq increases, energy

increases

gamma radiation/cool colors are

high energy

radio waves/hot colors are

low energy

optics

study of light rays and interaction

ray

wave of electromagnetic radiation, travels in straight line

reflection

bouncing light rays off surface

absorption

transfer of light energy to surface

refraction

bending light rays from 1 surface to another

pupil

opening where light enters

lens

focuses light

cornea

focuses light

retina

where light is projected, has photoreceptors

visual receptors

in retina, rods/cones

iris

colored part, controls size of pupil/how much light enters

sclera

white part, protects/holds eye structure

extraocular muscles

3 pairs, control eye mvt

conjunctiva

flaps, connects cornea to eyelid

optic nerve

send signals from 1 retina to brain

optic disc

where optic nerve leaves eye in retina, retinal vessels

optic disc =

blind spot

macula

has fovea, blood vessels, focuses light

fovea

has most cones, gives clearest vision, no blood vessels

nasal retina

gets visual info near nose

temporal retina

gets visual info near temples

pigment epithelium of retina

absorbs excess light

aqueous humor

fluid, maintains eye pressure/shape

zonule fibers

connects lens to ciliary muscle

ciliary muscle

contracts/relaxes zonule fibers

vitreous humor

jelly, keeps eye shape

blind spot

where optic nerve leaves eye in retina, no photoreceptors

cornea focuses ___%

80

lens focuses ___%

20

accommodation

lens, bring objects of diff distances closer

refraction happens in the

cornea

pulpillary light reflex

pupil size controlled by light

connections between retina and bs neurons control

muscles around pupil

more light = ___ pupil

smaller

less light = ___ pupil

bigger

visual field

what both eyes see when fixated on 1 point

light from bottom processed @

top

light from top processed @

bottom

visual acuity

ability to tell diff between 2 nearby points

visual angle

distance across retina, degrees

visual info travels pathway

photoreceptors, bipolar cells, ganglion cells

retinal processing is influenced by ___ & ___ cells

horizontal/vertical

horizontal cells

detect edges

vertical cells

direct info to brain

only light sensitive cells in retina are

rod/cones

ganglion cells are the only _____ and are the only retinal neurons that ___

output from retina, fire ap

pigmented epithelium

maintains photoreceptors, absorbs light passing thru retina

tapetum lucidem

light reflects back at photoreceptors, why cats eyes are bright when u shine light on them

ganglion cell layer has

ganglion cells

inner nuclear layer has

bipolar, horizontal, amacrine cells

outer nuclear layer has

photoreceptors

inner plexiform layer has

bipolar, amacrine, ganglion cell connections

outer plexiform layer is where ____ connect w bipolar/horizontal cells

photoreceptors

layer of photoreceptor outer segments have

light sensitive retina

pigmented epithelium has

outer segments

bipolar cells =

messengers

ganglion cells =

send final message to brain

amacrine cells =

editors/helpers

photoreceptors convert

electromagnetic radiation to neural signals

rods =

long, cylinder, 120 mil disks/retina, night

cones =

short, tapering, 6 mil disks/retina, day, color

rods are ___x more sensitive to light

1k

4 regions of photoreceptors

outer/inner segment, cell body, synaptic terminals

duplex retina

2 complementary systems in 1 eye

duplex retina makes ____, ____, and ____ conditions

scotopic, mesopic, phototopic

scotopic

low light

mesopic

dim light

phototrophic

bright light

central retina has ___ photoreceptors

less

peripheral retina has ___ photoreceptors

more

fovea has

cones

periphery has

rods

pit in retina is where

outer layers pushed aside, max visual acuity, all cones

photoreceptors transduce =

turn light energy to membrane potential

vision photoreceptors are

2nd messengers, gpcr

why are rods always depolarized in dark?

dark current/inward sodium

how phototransduction works

light bleaches rhodopsin, transducin g protein on, pde effector enzyme on, pde reduces cgmp, na channels close, membrane hyperpolarizes

in light, na __ coming in

stops

young helmholts trichromatic theory

3 diff cones control color perception, each sensitive to diff wavelengths

white =

all 3 cones on

color vision deficiency

cant tell color diff, 2/3 cones

mice have ___ cone that helps them see diff in ___

1, brightness

receptive field

part of retina where light changes neuron firing rate