Vision

Question 1

Scotopic vision

Answer 1

Monochromatic vision produced through the rods in low light.

Question 2

Photopic vision

Answer 2

Chromatic vision produced through the rods in low light.

Question 3

Dark current

Answer 3

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

Question 4

Hemidecussation

Answer 4

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.

Question 5

Optical illusion

Answer 5

Distortion of visual perception at the cortical level caused by previous experiences.

Question 6

Sclera

Answer 6

The outermost, white layer of the eyeball.

Question 7

Cornea

Answer 7

Frontal, transparent part of the sclera with the highest refracting power.

Question 8

Conjuntiva

Answer 8

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

Question 9

Iris

Answer 9

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

Question 10

Choroid

Answer 10

The middle, vascularised layer of the eyeball, including the iris and the ciliary body (ciliary muscles).

Question 11

Fovea centralis

Answer 11

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

Question 12

Blind spot (optic disc)

Answer 12

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.

Question 13

Musculus ciliaris

Answer 13

The lens is attached to the ciliary body (ciliary muscles) in the eye, it’s contraction is needed for accommodation.

Question 14

Glaucoma

Answer 14

Eye disease caused by an excessive intraocular pressure

due to a disturbance in the production and reabsorption of the aqueous humor.

Question 15

Cataract

Answer 15

Eye disease caused by an opacity of the lens.

Question 16

Presbiopia

Answer 16

In elederly people the lens looses it’s flexibility, thus accommodation is no longer possible for short distancesM corrected by reading glasses.

Question 17

Cis-retinal

Answer 17

Organic compound derived from vitamin A;

Question 18

Transducin

Answer 18

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

Question 19

Rhodopsin

Answer 19

Photopigment of the rods.

Question 20

Opsin

Answer 20

Protein part of the photopigment.

Question 21

Horizontal cell

Answer 21

Inhibitory interneuron in the retina connecting receptor cells.

Question 22

Amacrin cell

Answer 22

Interneuron in the retina establishing horizontal connections mostly close to the ganglion cells.

Question 23

Melanopsin

Answer 23

Photopigment contained by the W ganglion cells.

Question 24

M ganglion cell

Answer 24

Ganglion cell projecting to the magnocellular layer of the corpus geniculatum laterale.

Question 25

P ganglion cell

Answer 25

Ganglion cell projecting to the parvocellular layer of the corpus geniculatum laterale.

Question 26

Colour blindness

Answer 26

Disturbance of colour vision caused in most cases by a mutation in the gene coding
for the photopigments; the most common form is red/gren colour blindness.