vision

Question 1

as objects come closer what happens to the lens

Answer 1

lens thickens and increases refraction

Question 2

strength of lens defined by

Answer 2

diopters

Question 3

cornea bends light by __ diopters

Answer 3

48

Question 4

hyperopia

Answer 4

farsightness

eyeball too short

Question 5

where is image formed in hyperopia

Answer 5

in back of fovea

Question 6

hyperopia corrected by

Answer 6

convex lens

Question 7

myopia

Answer 7

nearsightness

Question 8

where is image formed in myopia

Answer 8

front of fovea

Question 9

myopia corrected by

Answer 9

concave lens

Question 10

astigmatism is

Answer 10

defect in cornea shape or lens shape

Question 11

astigmatism corrected by

Answer 11

adding barrel shape to specific areas of lens

Question 12

accommodation focuses image onto

Answer 12

fovea

suspensory ligaments attach elastic lens to circularly arranged ciliary muscles

Question 13

focusing on far objects, lens becomes what

and what innervation

Answer 13

lens thinner
sympathetic innervation(beta) from ciliary ganglion inhibit ciliary muscle contraction
radial tension on suspensory ligaments increased
refraction less
pupil diameter wider

Question 14

what happens during accommodation to near objects

Answer 14

ciliary muscles contract

relieve tension on suspensory ligaments

Question 15

what innervation responsible for accommodation to near objects

Answer 15

parasympathetic

Question 16

presbyopia is

Answer 16

impaired ability to focus on near objects

lens looses elasticity

Question 17

pupil constriction limits

Answer 17

limits incoming light, reducing scatter of light

improves focus

Question 18

in binocular vision

Answer 18

both eyes converge on object of interest

Question 19

rods purpose is

Answer 19

detection of photons

Question 20

where are rods found

Answer 20

lateral to fovea

Question 21

cones purpose

Answer 21

detection of photons and mediation of visual acuity

Question 22

where are cones found

Answer 22

fovea centralis

Question 23

only ___ cells have action potentials

Answer 23

ganglion

Question 24

fovea is center of

Answer 24

macula

Question 25

___cells synapse with cones

Answer 25

horizontal

Question 26

___ cells synapse from rods to cone circuits

Answer 26

amacrine

Question 27

unstimulated photoreceptors are

Answer 27

depolarized

Question 28

vision operates ___ compared to other neural circuits

Answer 28

opposite

Question 29

photoreceptors depolarzed to

Answer 29

-40

Question 30

glutamate does what

Answer 30

metabotropically inibits on bipolar cells via mGluR6 | iontropically stimulates off bipolar cells via AMPA and kainate receptors

Question 31

light sensitive portion of rhodopsin activates

Answer 31

G protein transducin which activates PDE

Question 32

gultamate release ceases as

Answer 32

Ca inside conc falls

Question 33

rhodopsin absorbs light at

Answer 33

505mm

Question 34

melanopsin function

Answer 34

detect darkness and release melatonin from pineal gland

Question 35

receptors synapse onto

Answer 35

bipolar cells

Question 36

presence of glutamate stimulates

Answer 36

off bipolar cells

Question 37

presence of GABA stimulates what

Answer 37

on center cells stimulate ganglion cells

Question 38

what is key elements involved in lateral inhibition circuits of retina

Answer 38

horizontal cells

Question 39

when stimulate horizontal cells release

Answer 39

GABA

Question 40

GABA does what

Answer 40

hyperpolarizes cones

Question 41

hyperpolarized cones do what

Answer 41

cease releasing glutamate | mediate detection of light

Question 42

GABA release from HC stops when

Answer 42

HC hyperpolarized aka unstimulated

Question 43

if photons strike only cones in off surround what happens to on center cones

Answer 43

become depolarized. glutamate release increased | off surround hyperpolarized

Question 44

off center ganglion cells wired to visual cortex to perceive

Answer 44

blackness

Question 45

lack of GABA from HCs stimulates

Answer 45

lateral inhibition mechanisms in retina

Question 46

visual cortex can process maximum of ___ images eper second

Answer 46

20-70

Question 47

shining light onto one pupil causes ___ constriction

Answer 47

ipsilateral/same side

Question 48

consensual light reflex demonstrated when

Answer 48

contralateral pupil also constricts

Question 49

absence of consensual light reflex in opposite pupil indicates

Answer 49

lesion in CN III

Question 50

ciliary reflex is stimulation of

Answer 50

sympathetic ANS division | Adelta fiber pain dilates pupil