Visual System

Question 1

Occipital cortex: awareness, recognition
visual memory?
Visual reflex?

Answer 1

memory: parietal + temporal lobe
reflex: brainstem, spinal cord
circadean: Diencephalon/ pineal gland

Question 2

entering light refracted by cornea, inverted by pupil

light projects to?

Answer 2

the fovea

Question 3

Protective layer of the retina

Answer 3

sclera

Question 4

Retinal blood flow

Answer 4

20% central retinal artery

80% choroid

Question 5

Retina Cell types
Layer 1: barrier from choroid/ contact photoreceptors

Layer 4: outer nuclear:

Layer 6: Inner nuclear:

Layer 8: Ganglion Cells

Answer 5

1- Retinal Pigmented Epithelial Cells (RPE) - phagocytose outer rod every 10 days

4- outer nuclear: cell bodies of cones/ rods

6: Inner nuclear: cell bodies of bipolar cells
8: Ganglion receive bipolar, project to optic nerve

Question 6

Produces the aqueous humor

Answer 6

Ciliary epithelium

Question 7

Cones:
S-
M-
L-

Answer 7

S- blue (sky blue)
M - green (little green monster)
L -Red (little red riding hood)

Question 8

Comprise the barrier between the retina and the choroid (also eats the rod outer segments every 10 days

Answer 8

Pigment cells

Question 9

Signal from photoreceptor to bipolar cells can be modified by?

Answer 9

Convergence: millions of photoreceptors project to fewer bipolar cells; there are interneurons (horizontal in outer and amicrine in inner of the inner nuclear layer)

Question 10

Tropism: where rods and cones have their own bipolar cells
Cones tropism in?
Rod tropism in?

Answer 10

Cones - center

Rods - periphery

Question 11

Ganglion cells that predominate in the peripheral retina and project to the magnocellular layer of the LGN

Answer 11

Alpha

Question 12

Ganglion cells that predominate in the central retina and project to parvocellular region of the LGN

Answer 12

Beta

Question 13

laterally interconnecting neurons having cell bodies in the inner nuclear layer of the retina of vertebrate eyes

They help integrate and regulate the input from multiple photoreceptor cells

Allow eyes to adjust to see well under both bright and dim light conditions

There is a greater density of horizontal cells towards the central region of the retina.

Answer 13

Horizontal

Question 14

Response of rods and cones to light

Answer 14

Decrese in cGMP, close the cGMP gated sodium channel and hyperpolarize the cells

Question 15

Has no horizontal/ amincrine cells
No convergence
Allows for crisp detail

Answer 15

Fovea

Question 16

Left visual field processed by?

Answer 16

Right visual cortex

Question 17

Loss of central vision (scotoma)

leading blindness in older pts

Answer 17

Macular degeneration

Drussen: protein accumulation

Wet: blood vessels grow into macula - significant visual loss (Avastin, VEGF inhibitor)

Question 18

General idea about the layers of the retina:

Inner -
Middle -
Outer-

Answer 18

Inner: Photoreceptors (phototransduction)

Middle: Bipolar

Outer: Ganglion –> optic nerve

Question 19

Childhood strabismus - comitant; no specific muscle weakness, no diplopia because the brain suppresses one image
can also occur when the brain “turns off” the visual processing of one eye to prevent double-vision, for example in strabismus (crossed-eyes).

Answer 19

Amblyopia

Question 20

any misalignment of the visual axis

Answer 20

strabismus

Question 21

Paralytic Strabismus is caused by?

Answer 21

weakness of one EOM

Question 22

Exo vs. Eso
Always present?

Only present during disrupted fusion?

Answer 22

Trophia

Phoria

Question 23

Etiology:

Eye is down and out, pupils non-reactive, ptosis

Answer 23

CN III complete palsy

PCOMM aneurism suspected (esp. if headache)