Vision Lecture Flashcards

1
Q

What is scotopic vision?

A

the function of the eye in very low light

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2
Q

What is mesopic vision?

A

at the threshold of cone vision in low light

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3
Q

what is photopic vision?

A

eye functioning under well lit conditions, color vision

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4
Q

what is the function of the 3rd eyelid?

A

keeps the eye moist, removes irritants from the eye, and shields the eye

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5
Q

objects in the retina are inverted onto the rentina. true or false?

A

true! our brain turns this backwards image right side up again

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6
Q

light rays are bent/refrracted the most at the _____

A

cornea

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7
Q

what is accommodation?

viewing distant objects requires ______ accommodation

viewing close objects require requires _____ accommodation

A

the process of refracting light rays to focus them on the retina

no

yes

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8
Q

the parasympatheitc system ____ pupils and _____ accommodation.

the sympathetic nervous system ____ pupils and ____the lens

A

contricts

promotes

dilates

flattens

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9
Q

what are the layers of the retina in order from back of the eye to front of the eye?

A

pigmented epithelium: nurtures the rods and cones, recycles photoreceptor discs

Photosensitive layer: where the rods and cones are

External limiting membrane: determines the boundaries of radial astrocytes that support retinal neurons

External nuclear layer: contains the nuceli of photoreceptors

External plexiform layer: synapses between photoreceptors and bipolar nuerons

Inner nuclear layer: nuclei of bipolar cells

Internal pleiform layer: synpase between bipolar neurons and ganglion nuerons

Ganglion layer: cell bodies and nuceli of ganglion

nerve fiber layer: axons from ganglion neurons

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10
Q

what is the tapetum lucidum for?

A

it is a reflective layer of cells behind the retina and it reflects the light back into the photoreceptors which boosts the ability to see in low light. HOWEVER it does reduce acuity

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11
Q

light causes a confirmational change in ______. This leads to _____ of the rod cell by closure of _____

A

retinal vitamin A derivative

hyperpolarization

sodium channels

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12
Q

dogs have a ____ system. Horses have ____

A

2 cone (green/yellow and blue)

red and blue cones but no green

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13
Q

what is the dazzle relfex?

A

when you shine a bright light into the eye and the eyelids should close. requires a functioning retina, optic nerve, optictract and midbrain, but does not require occipital cortex

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14
Q

what is the pupillary reflex?

A

reduction in pupil size hen there is a bright light. it should happen in both eyes.

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15
Q

what is the menace response?

A

cover one eye and with the other eye uncovered, move the hand towards the eye. this will elicit a learned menace response. it tests the integrity of cranial nerve pathways. requires cortical circuits to be present and cerebellar circuits. requires retina, visual pathways, visual cortex, and cranialnerve 2 to be in tact.

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16
Q

central processing occurs in what 3 locations?

A

the lateral geniculate visual cortex pathway

retinotectal pathway controlling pupillary reflexes

retinohypothalamic pathway important for circadian rhythms

17
Q

binocular vision offers what two things? which animals tend to have greater binocular vision?

A

stereopsis (depth perception)

binocular summation

predators since their eyes are more forward facing

18
Q

simple cells in the visual cortex respond to _____

complex cells respond to _____

A

lines placed in certain areas of the visual fields in certain oreintations

edges or lines in a particular orientation no matter where they are in the visual field

19
Q

where are the two streams from the visual cortex?

A

the dorsal stream: occipital lobe, pareital lobe, spatial location, the “where)

the ventral stream: occipital lobe, temporal lobe, visual identification, the “what”

20
Q
A