Visual Systems I

Front 1

Where is the Retina derived from?

Back 1

Diencephalon

Front 2

Where are the Cones found?

Back 2

Fovea

Front 3

What are the photoreceptors analogous to?

Back 3

somatosensory receptors

Front 4

T/F photoreceptors generate action potentials

Back 4

F. They release neurotransmitters (glutamate) in a graded fashion onto bipolar cells

Front 5

What is analogus to the DRG in the eye?

Back 5

the Bipolar cell

Front 6

What are the 2 "interneurons" in the middle layer of the retina?

Back 6

the horizontal cells that are in contact with bipolar cells and photoreceptors.

Amacrine cells thats are in contact with bipolar cells and ganglion cells

Front 7

what makes up the outermost layer of the retina?

Back 7

the ganglion cell

Front 8

Are ganglion cells myelinated?

Back 8

they are unmyelinated in the retina, but become myelinated once they exit the retina at the optic disk to form the optic nerve

Front 9

What is the only retinal cell that generates an action potential?

Back 9

Ganglion cell

Front 10

What's special about the Fovea?

Back 10

it is central 1 to 2 degree of visual space, central fixation point in each eye that is the region of highest visual acuity with the highest concentration of cones. bipolar cells and ganglion cells are displaced around to fovea in a manner that allows light (photons) to directly stimulate photoreceptors (primarily cones);

the brain precisely controls eye position to ensure images primarily land on the fovea

Front 11

Region around fovea (~3-5 mm) that corresponds to the central 5 degree of visual space, also an area of relatively high visual acuity

Back 11

macula

Front 12

what is the regoin in the visual field of no vision

Back 12

blind spot fool

Front 13

where does the optic tract go? be specific.

Back 13

90% goes to the LGN.

10% bipasses the LGN and forms the bracium of the superior colliculus which synapses in:
Superior colliculus (influence saccades)
Pretectal region (control pupillary light reflexes)
Suprachiasmatic nucleus of the hypothalmus (influence circadian rhythms

Front 14

What layer of cortex do the optic radiations synapse on?

Back 14

layer IV

Front 15

What is the proper name of Layer IV ?

Back 15

line of Gennari

this is why primary visual cortex is also called stiate cortex

Front 16

how much of the primary visual cortex is devoted to processing information from the fovea?

Back 16

50%

Front 17

Why is so much of the cortex devoted toward the fovea?

Back 17

1. has highest density of photoreceptors
2. Ganglion cells arise from the fovea have SMALL RECEPTIVE FIELDS; ganglion cells arising from the periphery of the retina have LARGE RECEPTIVE FIELDS

Front 18

RECEPTIVE FIELD:

Back 18

region of the retina where photons alter the firing of a neuron; for a retinal ganglion cell this area includes all the photoreceptors that are connected to the particular ganglion cell via bipolar cells

Front 19

Dorsal Stream

Back 19

analyzes WHERE (motion)

Front 20

Ventral Stream

Back 20

analyzes WHAT (color and form)

Front 21

When light hits the eye, what happens?

Back 21

it is inverted and reversed as it passes through the lens to land on the retina; thus, everything we see is upside down and backwards

Front 22

What does the superior temporal hemiretina see?

Back 22

inferior medial visual field

Front 23

What sees the superior medial visual field?

Back 23

the inferior temporal hemiretina

Front 24

what sees the superior lateral visual field?

Back 24

the iferior nasal hemiretina

Front 25

what does the superior nasal hemiretina see?

Back 25

the inferior lateral visual field

Front 26

What is a scotoma?

Back 26

blind spot where retina is non-functional

Front 27

what do scotomas look like if a pt recognizes them?

Back 27

they look like dark brown, purplish or white region.

Front 28

what information does the optic nerve carry?

Back 28

visual information from both the right and left (nasal and temporal) visual fields

Front 29

How the fuck would you get Quadrantinopia with macular sparing?

Back 29

retained vision in the center of the visual field due to collateral flow by MCA to the occipital pole

Front 30

What causes monocular vision loss?

Back 30

optic nerve lesion.

common causes are:
glaucoma, optic neuritis, elevated intracranial pressure, tumors

Front 31

Where is the optic disc in relation to the fovea?

Back 31

medial to it

Front 32

which is bigger. Fovea or macula?

Back 32

the macula surrounds the fovea

Front 33

bipolar cells in on-center arrangements have what type of receptor?

Back 33

MGluR6

Front 34

bipolar cells in off-center arrangements have what type of receptor?

Back 34

AMPA or KA-Type

Front 35

When do photoreceptors release glutamate?

Back 35

Dark