Light & Vision - Martin Flashcards Preview

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Flashcards in Light & Vision - Martin Deck (21):
1

Accommodation

Lens gets more curved/rounded --> more refraction

2

Spherical aberration

The peripheral of the lens is flatter, resulting in light being refracted more than in the center

3

Chromatic aberration

Different wavelengths are refracted differently

4

Emmetropia

Normal visual acuity

5

Anisometropia

One eye is different from the other

6

Myopia

- Near-sighted
- Eyeball is too long
- Corrected w/biconcave lens

7

Hypermetropia

- Far-sighted
- Eyeball is too short
- Corrected w/biconvex lens

8

Presbyopia

Loss of accommodation with age

9

What are some causes of diplopia?

Astigmatism
Strabismus: abnormal alignment of eyes
Amblyopia: uncorrectable loss of vision in one or both eyes

10

Rhodopsin

- Converts cis to trans-retinal leading to action potential in ganglion cell
- Post transduction: Na+ channel can't remain open w/o cGMP
- Dark: depolarization (Na+ influx, K+ efflux)
- Light: hyperpolarization (reduced Na+ influx, K+ efflux)

11

What is the difference between on-center and off-center ganglion cells?

On center cells send impulses when light strikes the center of the field, off center cells send impulses when light strikes the periphery of the field

12

Which pathway permits visual stimuli to be associated w/language, color and form?

Ventral stream/pathway

13

Which pathway processes the form and motion of the stimulus?

Dorsal stream/pathway

14

What is retinitis pigmentosa?

Normal removal and scavenging of retinal receptor membrane sheets or discs is impaired leading to less light arriving on the retina

15

What does the Young-Helmholtz theory postulate?

3 kinds of color reporting elements exist in the visual system (cones)

16

What does Hering's Opponent Process theory postulate?

Color vision postulated by 2 color elements (red & green reporting elements and blue & yellow reporting elements)

17

Which color vision theory is accurate?

Both! Young-Helmholtz explains how retinal cones process information while Hering explains how rental P cells and LGN cells process information

18

Which pigments are coded on the X-chromosome? Chromosome 7?

X: green and red sensitive
7: blue

19

Which cones are absent from the fovea?

Blue cones

20

Deuteranomaly

Defect in the middle wavelength sensitive pigment (green sensitive); still a trichromat

21

Deuteraopia

Absence of green sensitive cone; results in dichromatism