Neuro3 Vision

Front 1

They eye is a _____ instrument. This means light must be delivered to the retina in the optimal configuration to stimulate photorecetors

Back 1

Optical

Front 2

Functions of the eye involved focusing light, adjusting intensity of light, formation of _____ humor and protective functions like____ and _____

Back 2

Formation of the aqueous humor and protective mechanisms like blinking and lacrimation

Front 3

Regulation of the eyelid position??

Back 3

Blinking

Front 4

Blinking involves the use of smooth muscle and striated muscles what NT are used respectively?

Back 4

Smooth =Nonepinephrine on a adrenergic receptors
Striated= acetycholine on nicotinic receptors

Front 5

What occurs spontaneously , reflexly or in response to emotional stimula and is partially regulated by the parasymphathetic nervous system

Back 5

Tear production

Front 6

Tear production uses what NT and receptor?

Back 6

Acetycholine and muscarinic

Front 7

Eyelid movements are mediated by what muscles?

Back 7

Orbicularis oculi, levator palpebrea superioris and superior tarsal.

Front 8

What muscles are striated and require ACh to act on nicotinic receptors?

Back 8

Orbicularis Oculi and Levator Palpebrea superior

Front 9

The superior tarsal muscle is ? and is _____ innervated

Back 9

SM and sympatheticcally innervated

Front 10

Maintain ocular opening requires tonic activation of?? And inactivation of??

Back 10

LPS and ST activation
Inactivation of OO

Front 11

Gentle opening/closing, adjustment to changes in globe position depends on what muscles?

Back 11

Inactivation of OO
and activation/inactivation of LPS

Front 12

Blinking, firm closure of eyes is caused by?

Back 12

OO activation,
inhibition of LPS

Front 13

What functions does blinking serve?

Back 13

Visual info processing
corneal lubrication
eye protection

Front 14

The type of blinking is precisely conjugated, periodic, symmetrical, and originates in premotor brainstem structures that are highly influenced by dopaminergic activity

Back 14

Spontaneous blinking

Front 15

This type of blinking is decreased in Parkinson's patients and increased in schizoprenia and Huntington's disease

Back 15

Spontaneous blinking

Front 16

Initiated by either touch to cornea or by bright light/rapidly approaching objects?

Back 16

BLINK REFLEX

Front 17

Has afferents from 2 nerves, the trigeminal and optic nerve, which reflex am I

Back 17

Blink reflex

Front 18

The first layer of the tear film?

Back 18

Lipid secreted by oil glands in eyelids

Front 19

The 2nd layer of tear film?

Back 19

Comes from the lacrimal gland (contains lysozyme and other enzymes that protect against infection)

Front 20

The 3rd layer of tear film?

Back 20

Mucous from the conjunctiva

Front 21

What decreases with age?

Back 21

basal tear production

Front 22

What do emotional tears contain?

Back 22

More hormones like prolactin

Front 23

Parasympathetic stimulation produces what?

Back 23

Epiphora (overflow of tears)

Front 24

How is epiphora produced?

Back 24

Increasing tear production from the lacrimal gland.
Decreasing outflow by closing the lacrimal duct passage

Front 25

How can epiphora be produced? 2 ways

Back 25

Stimulation of cornea by CN V (reflex tears)
Strong emotional response mediated by limbic system

Front 26

Parasympathetic crying is accompanied by other symtons like what?

Back 26

Reddening of the face/convulsive breathing

Front 27

Cataracts, hyperopia, myopia, presbyopia and astigmatism are all types of?

Back 27

Refractive errors

Front 28

The cornea has greater____ power

Back 28

Refractive power

Front 29

The lens has a special characteristic for focusing power what is it?

Back 29

The lens can be adjusted

Front 30

The adjustment of the lens to allow for near vision?

Back 30

Accomodation

Front 31

As light passes thru cornea and lens the image is what?

Back 31

Inverted and reversed and refracted

Front 32

The cornea and lens have what type of surfaces that bend light to allow the image to be focused on the retina?

Back 32

CONVEX

Front 33

What is refactive power measured in?

Back 33

Diopters

Front 34

A normally refracting eye is said to be?

Back 34

Emmetropic

Front 35

Light waves from DISTANT sources require MORE or LESS refraction to be focused on the retina. This allows for the lens to be???

Back 35

LESS refration, so the lens can be relatively flat

Front 36

If the lens maintained a constant shape this means that the focal length doesn't change the image ends up?

Back 36

Behind the retina

Front 37

A strong (round) lens allows light from a ____ to focus on the retina?

Back 37

Near sourse

Front 38

The shape of the lens is controlled by which system?

Back 38

Autonomic nervous system

Front 39

Parasympathetics are active when a person is relaxed, like reading a book (near task) rounder lens. That means the sympathetics are activated during fight or flight so your lens is?

Back 39

Relatively flat

Front 40

What does the paraympathetic innervation in CN 3 cause the ciliary ganglion to do to ciliary muscle?

Back 40

Contraction of ciliary muscles=relaxation of circular fibers and lens ROUNDING

Front 41

What recpetors are stimulated in the parasympathetic ciliary ganglion?

Back 41

Muscarinic receptors

Front 42

Sympathetic nerves cause what to happen on the ciliary muscle and to the lens?

Back 42

Relaxes the ciliary muscle and the lens flattens

Front 43

Which receptors are stimulated in sympathetic nerves in the ey?

Back 43

B2 receptors

Front 44

The parasympathetic and sympathetic systems can be stimulated by agonists and blocked by antigonists indepenent of the other system. Receptor types affected?

Back 44

Muscarinic and B2 receptors

Front 45

Opacity of the lens due to physical trauma, radiation, high glucose concentration in DM patients or age?

Back 45

Cataracts

Front 46

How do you treat cataracts?

Back 46

Remove the lens

Front 47

Removing of the lens results in what?

Back 47

Hyperopia and loss of accomodation

Front 48

When images are focused behind the retina because the Axial length of the eye is less than the focal length? AL<FL Farsighted-ness

Back 48

Hyperopia

Front 49

Eye ball is to short?
Refractive power of the eye is abnormally weak?

Back 49

Axial hyperopia
Refractive hyperopia

Front 50

How do you correct hyperopia?

Back 50

Convex lenses with refractive power measured in positive diopters

Front 51

Myopia is

Back 51

Near sightnedness

Front 52

Images are focued in front of the retina?

Back 52

Myopia

Front 53

How do you correct myopia?

Back 53

Concave lens with RP measured in negative diopters

Front 54

Blurred vision when reduced malleability causes a decrease in the accommodative power of a lens (SIMILAR TO HYPEROPIA)

Back 54

Presbyopia

Front 55

The curvature of the cornea or lens is not equal in all meridians, causing unequal refraction and making a portion of the image out of focus?

Back 55

Astigmatism

Front 56

This instrumment is used to assess refractive errors in pts who cannot communicate with the examiner?

Back 56

Retinoscope

Front 57

In an emmetropic eye where will the red glow appear with the use of a retinoscope?

Back 57

Red glow appears suddenly and fills the entire pupil

Front 58

Myopic eye has the red glow appear?

Back 58

Side contralateral to where the light is.

Front 59

Myopic eye thru a retinoscope appears?

Back 59

Opposite side

Front 60

Hyperopic eyes have the glow appear on which side?

Back 60

Same side, as light movement

Front 61

What controls the amount of light entering the eye to keep it within the dynamic range of the photoreceptors?

Back 61

Iris sphincter

Front 62

Miosis is regulated by?

Back 62

The pupillary light reflex

Front 63

What causes contraction of the sphincter pupillae muscles?

Back 63

Parasympathetic fibers in Cn 3

Front 64

Mydriasis =

Back 64

dialation of the eye

Front 65

Mydriasis results from reflex activation of what fibers?? That stimulate the????

Back 65

Sympathetic fibers that stimulate the dialator pupillae

Front 66

Dialator pupillae receptors are stimulated by?

Back 66

A1 receptors

Front 67

Sphincter pupillae receptors stimulate?

Back 67

Muscarinic receptors

Front 68

Most common form of glaucoma is? It is caused by what?

Back 68

Open angle glaucoma. Results from overproduction of the aqueous humor

Front 69

Which is the most rapidly evolving form of gluacoma caused by a blockage of fluid outflow?

Back 69

Closed angle gluacoma

Front 70

What secretes aqueous humor? It is similar to protein free plasma and is found in both the anterior and posterior champeds. Normal pressure 20 mm Hg

Back 70

Ciliary epitheleim.

Front 71

What sympathetic nervous system NT and receptors cause increase cAMP levels which increase AQ production?

Back 71

B2 receptors and circulating epinephrine increase cAMP

Front 72

Stimulation of these receptors by nonepineprephrine decreases reduced aqueous humor procduction

Back 72

A2 receptors reduce cAMP

Front 73

An increase in what by the ciliary epithelieum increases AH volume?

Back 73

Cl-

Front 74

What regulates Cl- secreation?

Back 74

prodcution of bicarbonate by CARBONIC ANHYDRASE

Front 75

Drainage of AH occurs via 2 methods what are they?

Back 75

Canal of Schlemm *primary*
Relaxed ciliary muscles

Front 76

The canal of Schlemm allows for the iris to move away from the canal via?

Back 76

Miosis. Contraction of the sphincter pupillae moves iris away from canal

Front 77

What can exacerbate glaucoma by reducing drainage of the AH?

Back 77

Muscarinic antagonists or sympathetic a1 Agonists

Front 78

Reabsorbtion of AH thru ciliary muscles are facilitated by what?

Back 78

Prostaglandins PGF-2a

Front 79

Loss of vision is caused by comrpession of 4 structures

Back 79

Cornea, retina, optic nerve, arterial supply

Front 80

The halo effect when looking at a bright source of light is the result of vision loss by compression of?

Back 80

Cornea

Front 81

Vision loss by compression of photoreceptors?

Back 81

Retina

Front 82

Compression of arterial supply results in?

Back 82

Necrosis

Front 83

What is the inner layer of the retina? Middle layer? Outer layer?

Back 83

Ganglion cells that make up the optic nerve.
Middle- Bipolar cell bodies
Outer- photoreceptors (rods and cones)

Front 84

What lie inbetween the primary cell layers?

Back 84

Inner and outer synaptic layer

Front 85

what lie in the inner and outer synaptic layers?

Back 85

Amacrine and horizontal cells respectively

Front 86

These specialized glial cells span the entir retina

Back 86

Muller cells

Front 87

What cells in the retina cause transduction? What produce action potentioals?

Back 87

Rods and cones tranduce. Either rod or cone stimulates bipolar neurons which stimulation ganglion cells to make AP's

Front 88

Horizonatal and amacrine cells modulate the activity in bipolar and ganglion cells by producing?

Back 88

Lateral inhibition and contribute to ganglion cell receptive field proerties

Front 89

Two components detected by phot receptors? Which is color and which is brightness?

Back 89

Frequency and intensity. Frequency is color. Intensity is brightness

Front 90

What are dark adapted photoreceptors? What is the visible light wavelength?

Back 90

Rods- 350 nm to 750 nm

Front 91

Light that is percieved is ??? light. The a green object is detected as green because it ???? light of 530 nm

Back 91

Reflected light

Front 92

Rods are responsible for what type of vision? This type of vision occurs when?

Back 92

Scototopic- the monochromatic vision that occurs in low light

Front 93

There are how many types of cones and what are they?

Back 93

3 types. Blue=Short wavelength
Green=medium wavelength
Red long wavelenth

Front 94

The photopic vision is better for what?

Back 94

Discrimination of sufaces and movement under bright light

Front 95

Rods have more photopigment and a single pigment type which means?

Back 95

rhodopsin

Front 96

Single pigment type of rods falls between these 2 cones?

Back 96

Blue and green cones

Front 97

Rods have a smaler dynamic range and saturate in daylight due to?

Back 97

High sensitiveity (single photon)

Front 98

Lower temporal reslotution of rods correlates to?

Back 98

Slow response and signal integration

Front 99

The rods have poor spatial resolution since they are not in what? Have a high degree of convergence onto what cells?

Back 99

Not in fovea, onto the bipolar cells

Front 100

cones have less photopigments, and have a lot of overlap this allows for what?

Back 100

Different colors to produce different patters of activity

Front 101

Lower sensitivity means that they use multiple phones but they only saturate in ___ light and have a larger dynamic range

Back 101

INTENSE

Front 102

Good spatial resolution of cones due to?

Back 102

Concentration in fovea and low degree of convergence on bipolar cells

Front 103

The temporal resolution of cones is?

Back 103

HIGH, fast response due to less integration

Front 104

The ability to discriminate fine details of the visual scene is ?

Back 104

Visual acuity

Front 105

3 types of visual acuity?

Back 105

Spatial, Temporal and spectral

Front 106

The ability to resolve 2 pts in space is a function of 2 things?

Back 106

Spatial acuity. It is a function of loction and brightness

Front 107

Low acuity is what?

Back 107

Standing at 20 feet can only see letters that normal pop can see at 200 * 20/200 vision

Front 108

High acuity is

Back 108

20/15 person can see letters at 20 ft normal pop can see at 15 feet

Front 109

Acuity is assesed on which charts?

Back 109

Snellen

Front 110

Ability to distinguish visual events in time

Back 110

Temporal acuity

Front 111

When a flashing light appears to be continuous reather than repetitive. Is lower in the rods than in the cones

Back 111

Critical fusion frequency (CFF)

Front 112

Ability to distinguish difference in the wavelength of the stimuli?

Back 112

Spectral acuity

Front 113

Far red light can excite what?

Back 113

Cones

Front 114

Red light room allows for a person to perform high acuity actions without bleaching the rods and then allows them to move into dim light with out losing what?

Back 114

Dark adaption

Front 115

Phototransduction occurs via a 4 step process that uses what to amplify the signal?

Back 115

2nd messenger cascade

Front 116

In the rods, activation of the rhodspine results in the closure of what?? And _____ of the photoreceptor?

Back 116

Cyclic nucleotide gated Na channels and hyperpolarization of photoreceptor

Front 117

The first step of transduction in photorectpro? 1photon->

Back 117

Activation of receptor protein
1 rhodopsin

Front 118

What is the 2 step of transduction? 1 rhodopsin-> how many transducins?

Back 118

Activation of G protein transducin GTP-> GDP 1 rhodopsin->100 tranducin/s

Front 119

3rd step of transduction? 1 transducin-> how many PDE?

Back 119

Transducin activates the effector protein PHOSPHODIESTERASE. 100 PDE/s

Front 120

Falling concentrations of what cause tranduction channels to close decreasing the Na current? 1PDE->1000 GMP/s this decreases this compoundquickly

Back 120

cGMP

Front 121

Rods contain K leak channels that tend to ____ the membraie potential?

Back 121

Stabilize

Front 122

in the absence of light what are open?? This establishes an inward current that depolarizes the membrane

Back 122

cGMP dependent Na channels

Front 123

What is the resting rod photoreceptor potential

Back 123

-40 mV

Front 124

Photons activate phototransduction cascade leading to closure of cGMP-dependent Na channels and this causes what?

Back 124

Hyperpolarization of the membrane and a decrease in the release of exititory NT

Front 125

In this disorder there is a progress loss of rods to respond to light, night blindness is the first symptom followed by tunnel vision?

Back 125

Retinosis pigmentosa

Front 126

Non inflammatory damage to the retina often resulting from blocked blood supply?

Back 126

Retinopathy

Front 127

The visual cycle consists of bleaching and recycling what?

Back 127

11 cis retinol

Front 128

11 cis retinol is recycled between what 2 things?

Back 128

photoreceptors and the retinal pigment epithelium

Front 129

What is a keep component of dark adaptation in rods and is dirupted in vitamin A deficiency and macular degeneration?

Back 129

11-ci-retinol

Front 130

All visual pigments consists of what?

Back 130

Opsin and 11-cis-retinal

Front 131

Deficiency in what can lead to night blindness?

Back 131

Vitamin A

Front 132

What isomerizes 11-cis retinal to the transform resulting in opsin dissociates and bleaching?

Back 132

Activation of rhodopsin during phototransduction

Front 133

Once all-trans-retinal is in the retinal pigment epithelium it is either _____ or _____ back to the photoreceptors completing the visual cycle

Back 133

Stored or converted back to 11-cis-retinal

Front 134

Recycling of ???? is a key part of dark adaptiation

Back 134

rhodopsin

Front 135

Cone recycling is much ??? than rod recycling is

Back 135

Faster. since the enzymes are in the cones themselves

Front 136

What acts in the place of RPE for storage of cone photopigments?

Back 136

Muller's cells

Front 137

Vitamin A is fat soluble and necessary to make 11--cis-retinol. If you lack it what happens?

Back 137

Night blindness, dry skin/hair, decreased ability to fight infections

Front 138

Drusen are?

Back 138

Yellow deposits characteristic of age related macular degeneration (AMD)

Front 139

Two forms of AMD. what happens in each briefly?

Back 139

DRY- atrophy of RPE and loss of photoreceptors
WET- worse-- loss of central visian, caused by abnormal BV growth in chorioid