Vision

Front 1

Blind spot, answer either (1) In terms of anatomy, why is this found on the temporal VISUAL field? or (2) Why is that area blind?

Back 1

because the optic nerve exits the eye on the nasal RETINAL field, there can be no receptors where the optic nerve exits the eye

Front 2

Why would you have tunnel vision in retinitis pigmentosa?

Back 2

loss or rods in the mid-periphery

Front 3

Glaucoma: answer either (1) What compartment does not drain properly in this disorder? or (2) What is the mechanism of loss of vision (blindness) [e.g. media lose their transparency, refractory error, etc].

Back 3

aqueous humor (anterior chamber) ganglion cells (the ones that form the optic nerve) degenerate

Front 4

"A laser is used to destroy patches of the retina." Answer either (1) Who might actually benefit from this procedure? or (2) Why would the ophthalmologist avoid blasting the fovea with the laser?

Back 4

a diabetic, fovea is too essential for high acuity color vision at the point of fixation

Front 5

What kind of people would have the focussed image in front of the retina instead of on the retina?

Back 5

near-sighted people

Front 6

If the ciliary muscle is contracted, what happens to... (answer one of these) (1) the suspensory ligaments, or (2) the shape of the lens, or (3) your eyesight?

Back 6

they become slack, it gets rounder, for near vision

Front 7

"Eye care professionals dilate the pupil with belladona alkaloids." Pretend this is all you know and then explain, on that basis, what output from the parasympathetic nervous system does to the pupil.

Back 7

drug blocks parasympathetic neuro-effector junction, so parasympathetic must do opposite, constrict

Front 8

"A single rod can 'see' one photon of light." How is it that such a cell physiology piece of knowledge was first established on the basis of ordinary people like you and me indicating whether or not they could see various light stimuli?

Back 8

psychophysics, careful calibrations, careful measurements, showed only 6-14 quanta absorbed over a 500 rod area

Front 9

A cis to trans isomerization of what chromophore, (name that chromophore), a component of a G protein coupled receptor, is the only thing light actually does in visual transduction?

Back 9

11-cis retinal (retinene) the aldehyde of vitamin A

Front 10

I suggested that a gene duplication on the X chromosome could be used to explain how the superfamily of G protein coupled receptors evolved. Which two proteins are made by the two duplicated X chromosomal genes I am referring to?

Back 10

the genes for red- and green-absorbing rhodopsins

Front 11

Rhodopsin signals to a G protein and the G protein signals to what enzyme? Answer for either the vertebrate or for the fruit fly. Hints: cGMP is involved in the vertebrate rod and the fly utilizes the phosphoinositide signal transduction cascade.

Back 11

a phosphodiesterase that converts cGMP

Front 12

Coated pits and multivesicular bodies are involved in recycling of photoreceptive membrane in fruit flies. By contrast, for vertebrate rods, an additional type of cell is needed in the phagolysosomal system. What is this cell called?

Back 12

retinal pigmen epithelium

Front 13

Why are you blind in your blind spot?

Back 13

No receptor cells can be presen t where the optic nerve exits and the blood supply enters and exits

Front 14

What happens to your vision when the ciliary muscle is contracted?

Back 14

When ligaments become flaccid, the lens gets rounder, accommodating for near vision

Front 15

"Night blindness," "ring scotoma," and "tunnel vision" are symptoms of what disorder?

Back 15

Retinitis pigmentosa

Front 16

Which portion of the nervous system connects to the iris to mediate the constriction of the pupil elicited by a light stimulus?

Back 16

Parasympathetic, occulomotor nerve (#3), from ciliary ganglion

Front 17

Why is there lutein in your vitamin pill?

Back 17

This is one of the carotenoids in the macular pigments that protect foveal cones from blue light

Front 18

Young and Helmholtz proposed a widely accepted theory of trichromatic color vision in humans. Answer either (1) what kind of cell, or (2) what kind of molecule has these three specific peak wavelengths of sensitivity?

Back 18

Cone rhodopsin

Front 19

Why is it more accurate to refer to women heterozygous for red or green blindness as "mosaics" instead of "carriers?"

Back 19

since it is on the X, they have some cells with one X and the rest of their cells have the other X

Front 20

In Prof. Stark's research seminar, the rhodopsin promoter or the heat shock promoter was used to drive expression of rhodopsin labeled with green fluorescent protein into the rhodopsin-containing organelle that mediates vision. On what kind of molecule is a promoter?

Back 20

The promoter is the part of the gene upstream of the coding sequence (thus DNA)

Front 21

Prof. Stark showed transmission electron micrographs from his own work and work from other researchers of big vesicles in the visual cell that he believed carried rhodopsin into the rhodopsin containing organelle that mediates vision. What cell structure would have produced these vesicles?

Back 21

Rough endoplasmic reticulum via Golgi apparatus

Front 22

State a major difference between retinitis pigmentosa and age related macular degeneration.

Back 22

Rods (as young adult) ve cones (in elderly)

Front 23

State one of the three fundamental functions of the retinal pigment epithelium.

Back 23

Black "paint," retinoid metabolism, phagocytosis of distal tips of rods that are shed daily

Front 24

The aldehyde of vitamin A (retinal, formerly called retinene) is hit by light. What happens to it?

Back 24

It bends [isomerizes] (it relaxes from 11-cis to all trans)

Front 25

Under what circumstances is there lots of cGMP to open the channels in the rod outer segment?

Back 25

In the dark

Front 26

In Prof. Stark's research seminar, a recent suggestion was that clathrin was associated in an "import" pathway (rough endoplasmic reticulum to Golgi apparatus to the organelle where rhodopsin mediates vision). More traditionally, for many decades, clathrin was seen (in what structure?) in the transmission electron microscope.

Back 26

Coated pits, coated vesicles, endocytitic structures, clearance

Front 27

In what context is vitamin A relevant to a G protein coupled receptor?

Back 27

The aldehyde of vitamin A is the chromophore that attaches to the protein rhodopsin (which is a G protein coupled receptor)

Front 28

What intracellular ligand, whose function is to open channels, is decreased when light stimulates a rod?

Back 28

cGMP

Front 29

Energy equals Planck's constant times the frequency. Energy of what?

Back 29

of one photon

Front 30

For what population of people is macular degeneration most common?

Back 30

elderly

Front 31

What must be bound to the G-protein-coupled-receptor protein to make the fully-functional rhodopsin molecule that absorbs light?

Back 31

retinal

Front 32

What happens to a rod's neurotransmitter release when light hits the rod?

Back 32

decreases

Front 33

The ciliary muscle contracts, in accomodation, to let you do what?

Back 33

see up close

Front 34

How does an eye care professional test for glaucoma?

Back 34

poke the eye for a pressure check

Front 35

In the dark, a current of Na+ ions flows from the sodium pump in the inner segment through what in the outer segment?

Back 35

channels

Front 36

When an axon from a ganglion cell goes toward the brain in the optic nerve, where does it first synapse?

Back 36

thalamus

Front 37

What layer at the back of the eye is black?

Back 37

retinal pigment epithelium, also choroid

Front 38

Some men taking Viagra (sildenafil) report impaired color vision. Why might this be?

Back 38

Viagra and phototransduction both involve cGMP

Front 39

Where are the genes of the long- and middle-wavelength cone rhodopsins located?

Back 39

X chromosome

Front 40

Our gaze seems more relaxed for far vision even though suspensory ligaments are relaxed for the lens to accomodate for near work. What does contract to change the lens shape to see up close?

Back 40

ciliary muscle

Front 41

A current of Na+ in the dark along the rod is from the Na+-K+ pump in the inner segment and what in the outer segment?

Back 41

Na+ channel (or transduction machinery)

Front 42

What specific cellular defect explains the tunnel vision (ring scotoma) of retinitis pigmentosa?

Back 42

rods degenerate

Front 43

What is the only direct effect of light in initiating phototransduction?

Back 43

cis -> trans isomerization of retinal

Front 44

What kind of lens corrects for myopia (near-sightedness)?

Back 44

Concave

Front 45

Which two rhodopsins used for human color vision are coded by adjacent genes on the X chromosome?

Back 45

middle and long wavelength (green and red [yellow])

Front 46

Ganglion cells are killed from high eye pressure. What is this disorder called?

Back 46

glaucoma

Front 47

What layer of black cells supports rod outer segments by phagocytosis and conversions of vitamin A?

Back 47

retinal pigment epithelium

Front 48

Epinephrine binds one G protein-coupled receptor (GPCR). What other GPCR, used for vision, is a pigment that contains a form of vitamin A?

Back 48

rhodopsin

Front 49

As it applies to diabetic retinopathy, what is angiogenesis?

Back 49

formation of new, fragile, blood vessels

Front 50

Laser photocoagulation decreases angiogenesis. Here we are treating to prevent further blindness from what disorder?

Back 50

diabetes

Front 51

Which side of the retina projects to the ipsilateral lateral geniculate body at the optic chiasm?

Back 51

temporal

Front 52

Macular degeneration (MD) aflicts a certain population as reflected by the "A" in the name (AMD). What population?

Back 52

elderly (A=age-related)

Front 53

Under what conditions are cGMP levels in the rod lowered?

Back 53

when stimulated by light

Front 54

Why is it inaccurate to consider a chromosomally normal woman to be be a carrier for a recessive X-linked color blindness if the other chromosome is normal (wild-type, dominant)?

Back 54

mosaic of cells with one vs the other X functioning (Mary Lyon X inactivation hypothesis)

Front 55

Why does each eye have a blind spot?

Back 55

there can be no receptors where the optic nerve exits

Front 56

Why is cataract usually a less severe form of blindness than retinitis pigmentosa?

Back 56

there is straightforward surgery for cataract, whereas rods die and cannot be recovered for rp

Front 57

Scientific information has led to the decades-old conventional wisdom that vitamin A is good for vision. Other than being the pigmented portion of rhodopsin, where else do carotenoids come in to play, explaining why lutein is a dietary supplement or a component in a multi-vitamin pill?

Back 57

macular pigments protect fovea from blue light

Front 58

Presbyopia is a defect in what process that affects most people over 40 years old.

Back 58

accomodation

Front 59

Why is the cornea actually a stronger lens in the eye than the lens?

Back 59

because of the big change in index of refraction from the air-cornea interface

Front 60

Why is the rod depolarized in the dark (but not in the light)?

Back 60

because cGMP opens sodium channels

Front 61

The genes for the yellow- and green-light absorbing rhodopsins are near each other on which chromosome?

Back 61

X

Front 62

The tip of the rod outer segment is sloughed off on a daily basis and "recycled." Where does this cellular fragment go?

Back 62

into retinal pigment epithelium

Front 63

What does activation of the parasympathetic portion of the occulomotor nerve do to the pupil?

Back 63

closes

Front 64

If your eye pressure is high, answer ONE of the following: (1) name of disorder, (2) what is not draining appropriately, or (3) loss of what cells mediates vision loss?

Back 64

glaucoma, aqueous humor, ganglion cells

Front 65

How can rhodopsin be mutant yet the patient still can see until retinitis pigmentosa first presents in the teens or 20's?

Back 65

in autosomal dominant, a normal recessive gene still expresses rhodopsin

Front 66

Suppose you could stimulate a nerve to achieve the same effect as applying belladonna alkaloids to the eye. What type of nerve would you stimulate?

Back 66

sympathetic

Front 67

A whole lot of rods converge onto each ganglion cell. What does this wiring achieve?

Back 67

sensitivity

Front 68

What is lost in age related macular degeneration (AMD)? (Your answer can be cellular or functional.)

Back 68

cones, fovea; vision

Front 69

If you stare straight at a mark (X), while a stimulus is presented to both eyes to the right of the X, describe how the stimulus projects to the thalamus (lateral beniculate nucleus).

Back 69

temporal retina of left eye - ipsilateral projection; and nasal retina of right (contralateral) to left

Front 70

In the molecular mechanism from light absorption to hyperpolarization of the rod, exactly what does 11-cis retinal do?

Back 70

absorb light, convert to trans

Front 71

Why would you see much better under water with vs without goggles?

Back 71

keep the normal air-cornea interface (with the normal indices of refraction)

Front 72

"The blind spot is about 15o off fovea in your nasal retinal field (temporal visual field)." Translate.

Back 72

location off axis is measured in angle, since the optic nerve exits 15o on the side toward the nose, the inversion of the image would make it seem 15o off to the side

Front 73

"Visual experience can influence the progression of myopia." On what basis can that statement be made with scientific authority?

Back 73

research where the vision was distorted with goggles and the eye changed

Front 74

"If the ciliary muscle is relaxed, the ligaments are tight and" Finish this thought with respect to the shape of the lens and what that does for vision.

Back 74

lens flattens for distance vision

Front 75

In the course a lifetime, a retinal pigment epithelial cell's ability to carry out it's function might deteriorate. Why?

Back 75

it fills with the indigestibloe residue of the phagolysosomal system

Front 76

If you were convinced that blue light damages foveal cones, how might you alter your diet starting now, while you are young, to delay age related macular degeneration (AMD)?

Back 76

eat veggies or vitamin pills with lutein or zeaxanthin

Front 77

With what sort of methodology were scientists as early as 1942 able to come to the conclusion that a rod can respond to one photon?

Back 77

psychophysics, human subjects report if they can see calibrated lights

Front 78

"A derivative of vitamin A is the chromophore of rhodopsin." Translate.

Back 78

vitamin A aldehyde is the light absorbing portion attached to the protein

Front 79

Why would the evolution of red-green color vision on the X chromosome relate to the richness of olfactory sensation?

Back 79

it is a simple example of the evolution of G protein-coupled receptors

Front 80

"Color normal is dominant, color blind is recessive, hence women can be heterozygous carriers for green blindness." Why is this an oversimplification?

Back 80

they would be mosaics of cells with one or the other X functioning

Front 81

Why is there an extracellular current from the rod outer segment to its inner segment in the dark?

Back 81

The channel letting Na+ in is in the OS, the sodium pump is in the IS

Front 82

In terms of the channel gating, why does a rod hyperpolarize in response to light?

Back 82

the ligand (cGMP) that holds the Na+ channel open is broken down

Front 83

You stare at an X with your right eye. Answer either (1) Where would the blind spot be? (state this using the sort of terminology that might be used in optometry) Or (2) How would you determine where it is while you are staring at the X?

Back 83

a certain angle (about 15 degrees) off axis (away from the fovea) in the temporal visual field (nasal retinal field)

Front 84

A muscle that mediates accommodation contracts. Answer either (1) What happens for your vision? Or (2) What happens to the shape of the lens?

Back 84

(1) better for near vision (2) becomes rounder

Front 85

"The loss of vision is referred to as a 'ring scotoma.'" Answer (1) What disorder? Or (2) Why is it a ring?

Back 85

1-retinitis pigmentosa, rods (in mid-periphery) are lost

Front 86

Which portions of the nervous system mediate constriction and dilation of the pupil?

Back 86

parasympathetic (constriction) and sympathetic (dilation)

Front 87

One photon absorbed by rhodopsin elicits an electrophysiological response in a rod. That plus what retinal wiring consideration makes scotopic vision tremendously sensitive?

Back 87

convergence of multiple rods to one ganglion cell

Front 88

Why does the retinal pigment epithelial cell have so much to phagocytose?

Back 88

tips of outer segments are shed daily

Front 89

How (between New World monkeys and Old World monkeys) did there get to be (at least) two color vision genes on the X chromosome?

Back 89

unequal crossing over duplicated the gene

Front 90

What is the only thing that light does directly to excite rhodopsin?

Back 90

cause 11-cis to all trans isomerization of retinal

Front 91

A light is switched on. What happens to the transmitter release from the rod?

Back 91

decreased

Front 92

The eye pressure is high. Answer either (1) What isn't draining properly? (2) Death of what cell type would mediate vision loss? Or (3) What is this condition called?

Back 92

Aqueous humor, ganglion cell, glaucoma

Front 93

Why would a person with my interests need to use Planck's constant?

Back 93

Since it gives energy of a photon, it can assist in calculations of light intensity

Front 94

When an ophthalmologist looks at your retina, what is the second most conspicuous landmark after the optic disc?

Back 94

Macula (fovea)

Front 95

What does the Mary Lyon X inactivation hypothesis have to say about heterozygous carriers of red or green colorblindness (both of which are on the X)?

Back 95

It should not be a matter of dominant vs recessive, but her retina must be a mosaic

Front 96

What is it that allows the sodium channel in the rod outer segment close?

Back 96

Removal of cGMP by phosphodiesterase

Front 97

In the visual projection, where is the first place where inputs from both eyes can connect to the same cell?

Back 97

Not until the cortex

Front 98

What is lost making people with age related macular degeneration (AMD) blind?

Back 98

Cone (foveal) vision

Front 99

How is vision changed when suspensory ligaments are relaxed?

Back 99

lens rounder for near vision

Front 100

What would output from the occulomotor nerve (cranial nerve #3), connecting through the ciliary ganglion, do to vision in bright light?

Back 100

parasympathetic constrict pupil to decrease that bright light to retina

Front 101

Who was short-changed by the bottleneck proposed for the evolution of color vision?

Back 101

early mammals

Front 102

Why might you expect that medications like Viagra for erectile dysfunction might affect vision?

Back 102

It inhibits cGMP phosphodiesterase

Front 103

Fish, birds and mice can see ultraviolet light but you cannot. What is the difference between their eyes and yours in this regard?

Back 103

obviously, their lenses must transmit UV, also their retinas have UV receptors

Front 104

What happens to the vision of a fruit fly in a mutant that has degeneration of the predominate receptor type, R1-6?

Back 104

R1-6's contribution to response is abolished, leaving R7 (with its UV sensitivity) and R8 contributing to physiological and behavioral response

Front 105

How was it first shown, a few decades ago, that there were environmental (not just genetic) influences in progressive myopia?

Back 105

vision changed in chicks pecking for seeds if they were fit with goggles

Front 106

What part of the eye is at fault when the subject experiences floaters?

Back 106

vitreous

Front 107

"Ring scotoma." Answer either (1) Why a ring? Or (2) What is the name of this disorder?

Back 107

since rods are off fovea, ring of rod blindness is around fovea

Front 108

A pigment that looks yellow and absorbs blue light is situated in the light path on the way to the foveal cones. Answer either (1) What is it made of? Or (2) How might it be useful in terms of visual health?

Back 108

carotenoids (zeaxanthin and lutein), might prevent or delay age-related macular degeneration

Front 109

Either remember or figure out from what I remind you. Planck's constant (h) is 6.63 x 10­p;34 (what units?) E is energy, frequency (n)= speed of light divided by wavelength of light. E=hn.

Back 109

joules-sec

Front 110

Phagocytosis by the retinal pigment epithelium (RPE). Answer either (1) What is phagocytosed? Or (2) Describe, in some way, the burden this imposes on the RPE cell.

Back 110

distal tips of rods, postmitotic cells last a lifetime and such high traffic leads to accumulation of age pigment

Front 111

What is the next molecule in the cascade directly after the G protein (transducin) is activated?

Back 111

cGMP phosphodiesterase

Front 112

I can see 350 nm light but you cannot. Why can't you see UV (ultraviolet) light?

Back 112

your lens blocks it

Front 113

Give the approximate wavelength for the peak sensitivity of human rods?

Back 113

500 nm

Front 114

When it was first introduced by Harris, Stark and Walker in 1976, what was the sev (sevenless) mutant used for?

Back 114

to show that R7 was a UV receptor, to show the contribution of R7 to the (spectral) responsivity of the eye

Front 115

What happens to the vision of a vitamin A deprived mouse after it has had vitamin A replacement therapy?

Back 115

since it was very low, it comes up, it comes up in the UV especially