13. Vision Flashcards Preview

2. Physiology and anatomy > 13. Vision > Flashcards

Flashcards in 13. Vision Deck (26)
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1
Q

scotopic vision

A

monochromatic vision produced through the rods in the low light

2
Q

photopic vision

A

chromatic vision produced through the cones under well-lit conditions

3
Q

dark current

A

contionous inflow of Na+ and Ca++ into rods and cones in dark through cGMP-regulated channels, causing hypopolarization and glutamate release

4
Q

hemidecussation

A

partial crossing of optic fibers in the chiasma opticum ensuring that information collected from the same part of the visual field by the two retinas is analyzed in the same hemisphere

5
Q

optical illusion

A

distortion of visual perception at the cortical level caused by previous experiences

6
Q

sclera

A

the outermost, white layer of the eyeball

7
Q

cornea

A

frontal, transparent part of the sclera with the highest refracting power

8
Q

conjunctiva

A

very sensitive epithelial membrane covering the sclera and cornea and lining the inside of the eyelids

9
Q

iris

A

circular, pigmented membrane behind the cornea, perforated by the pupil; its contraction regulates the amount of light passing into the eye

10
Q

choroid

A

the middle, vascularized layer of the eyeball, including the iris and the ciliary body (ciliary muscles)

11
Q

fovea centralis

A

a depression in the center of the macula of the retina, the area of the most acute vision, where only cones are present

12
Q

blind spot (optic disc)

A

the spot on the retina, where the axons of the ganglion cells and blood vessels penetrate the wall of the eyeball; no receptor cells are found here

13
Q

muscular ciliaris

A

the lens is attached to the ciliary body (ciliary muscles) in the eye, its contraction is needed for accomodation

14
Q

glaucoma

A

eye disease caused by the excessive intraocular pressure due to a disturbance in the production and reabsorption of the aqueous humor

15
Q

cataract

A

eye disease caused by an opacity of the lens

16
Q

presbiopia

A

in elderly people the lens looses its flexibility, thus accomodation is no longer possible for short distances; corrected by reading glasses

17
Q

cis-retinal

A

organic compound derived from vitamin A; in visual pigments it absorbs the energy of photons

18
Q

transducin

A

G-protein in rods and cones, activated by the photopigment during light detection

19
Q

rhodopsin

A

photopigment of the rods

20
Q

opsin

A

protein part of the photopigment

21
Q

horizontal cell

A

inhibitory interneuron in the retina connecting receptor cells

22
Q

amacrin cell

A

interneuron in the retina establishing horizontal connections mostly close to the ganglion cells

23
Q

melanopsin

A

photopigment contained by the W ganglion cells

24
Q

M ganglion cell

A

ganglion cell projecting the magnocellular layer of the corpus geniculatum laterale

Corpus = body

25
Q

P ganglion cell

A

ganglion cell projecting the parvocellular layer of the corpus geniculatum laterale

Corpus = body

26
Q

color blindness

A

disturbance of the color vision caused in most cases by a mutation in the genes coding for the photopigments; the most common form is the red/green color blindness