Visual System Part 2

Question 1

Rod discs contain these proteins

Answer 1

Rhodopsin- responds to mostly blue

Question 2

Cone discs contain these proteins

Answer 2

Iodopsin- blue, green, red

Question 3

Discs of photo receptors get created by this organelle

Answer 3

Golgi apparatus

Question 4

Light diminishes _______ release from receptors

Answer 4

Glutamate

Question 5

Light converts 11-cis retinal to _______

Answer 5

Trans-retinal

Question 6

Light stimulates opsin to send signal to

Answer 6

Phosphodiesterase (PDE), which binds to cGMP—>GMP

Question 7

Lack of cGMP, by PDE attachment results in this action on Na+ channels

Answer 7

Closes Na+ channels.

Question 8

Function of rods

Answer 8

Peripheral; do not code for color. Night vision. Sensitive to scattered light.

Question 9

Function of cones

Answer 9

Code for color, concentrated in fovea, spread out thinly to provide peripheral color vision. Sensitive to direct axial light

Question 10

In order from anterior to posterior: Rods/cones, pigment epithelium, and _______

Answer 10

Choroid

Question 11

Why are rods/cones against the choroid on the back of the retina?

Answer 11

Waste products created. Blood is supplied by the choroid, and provides oxygen, nutrients, and turnover system for the rods/cones

Question 12

Light that passes rods/cones is later absorbed by

Answer 12

Melanin in the epithelium. Part of visual acuity. Lessens the impact of light

Question 13

Blue light generates _______. The eye contains ______ to protect itself from this.

Answer 13

ROS

Melanin

Question 14

Maintenance of excitability occurs by this

Answer 14

Conversion of trans-retinal to 11-cis-retinal. In the epithelium, Then this cis formation gets taken back to the rods/cones

Question 15

Epithelial tight junctions controls the passage of these substances

Answer 15

Glucose, Vitamin A, Cl-, H2O

Question 16

Water and ions return through the retinal pigmented epithelium (RPE) into

Answer 16

choroid veins. Lymphatic passageway, partially to keep fovea avascular

Question 17

Retinal detachment occurs because of this

Answer 17

Retina contact with retinal pigmented epithelium is not very strong

Question 18

Macular degeneration is due to these 2 things

Answer 18

Wet- rupture of blood vessel

Dry- build up of cellular waste

Question 19

Horizontal cells communicate this

Answer 19

From cones/rods to other ones. They determine how active the signal from cones and rods to bipolar cells—->ganglion cells are going to be

Question 20

Optic tract contains this

Answer 20

Meninges (dura, subarachnoid space with CSF, pia mater)

Question 21

This CNS glia surrounds the axon of the optic nerve

Answer 21

Oligodendrocyte is the chief myelinating cell in the CNS

Question 22

Astrocytes are here

Answer 22

Connect axons to the outside of the nerve tract, and connect to blood vessels

Question 23

Papilledema is edema under this structure

Answer 23

Optic disc. There is increased pressure behind the retina due to high CSF pressure

Question 24

Papilledema causes this to the veins

Answer 24

Fat tortuous veins form, and axoplasmic stasis of ganglion cells occurs