vision and the eye Flashcards

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1
Q

what is the stimulus for vision?

A

electromagnetic energy or light waves

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2
Q

what is the lens?

A

elastic structure that changes to help focus

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3
Q

when the lens becomes thinner, it is focusing on objects that are?

A

far away/more distant

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4
Q

what is the retina?

A

a multi-layered structure at the back of the eye that contains light-sensitive photoreceptors

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5
Q

what is the function of the retina?

A

light-sensitive photoreceptors transduce light into electrical impulses

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6
Q

what is the cornea?

A

transparent protective structure at the front of the eye

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7
Q

what is the pupil?

A

and adjustable opening behind the cornea

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8
Q

what is the function of the pupil?

A

controls the amount of light that enters the eye through iris muscles

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9
Q

when pupils dilate, they? when pupils constrict, they?

A

get bigger; get smaller

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10
Q

what does your ability to see clearly depend on?

A

being able to accurately focus an image directly into your retina

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11
Q

what is myopia? people with myopia have difficulty seeing?

A

nearsightedness; difficulty seeing far away objects

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12
Q

what is hyperopia? people with hyperopia have difficulty seeing?

A

farsightedness; difficulty seeing up close objects

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13
Q

what are the two types of light sensitive cells found in the retina?

A

rods and cones

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14
Q

what are rods?

A

photoreceptors that contribute to black and white vision and are more sensitive to light then cones

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15
Q

what is the fovea?

A

the center of the retina that increases in concentration through the periphery of the retina

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16
Q

what are cones?

A

contribute to perception of color and detail and functions best in high illumination

17
Q

what does the fovea only contain?

A

cones!

18
Q

what are bipolar cells?

A

receive signals from rods and cones to form a synapse with them

19
Q

which light sensitive cells is typically connected to bipolar cells?

A

rods! greater sensitivity to light

20
Q

what do the ganglion cells do?

A

form a synapse with the bipolar cell

21
Q

the axons of the ganglion cell form the?

A

optic nerve

22
Q

what is the pathway of transduction?

A

rods/cones –> bipolar cells –> ganglion cells –> optic nerve

23
Q

what cells modulate the signals of transduction?

A

horizontal and amacrine

24
Q

what are photopigments?

A

protein molecules in the retina

25
Q

what is the reaction of photopigments critical for?

A

visual transduction

26
Q

photopigments undergo what type of reaction to transduce a light signal into neural code?

A

isomerization

27
Q

photopigment cells need time to?

A

regenerate

28
Q

what is the blind spot

A

axons that form the optic nerve create a blind spot with no photoreceptors

29
Q

what are dark adaptations?

A

the progressive improvement of brightness sensitivity in low lighting conditions

30
Q

the process of dark adaptation revolves around?

A

changes in the proportion of photopigments that are ready to transduce light to used photopigments in the process of regenerating

31
Q

do rods or cones take longer to regenerate?

A

rods

32
Q

what is pigment bleaching?

A

being temporarily ‘blinded’ by a bright light because the photopigment supply is depleted and must regenerate before transduction can occur again

33
Q

how many types of photopigment do rods have?

A

one

34
Q

what color of photopigment are rods most sensitive to?

A

blue (shortest wavelength)