The visual system

Question 1

what are the only cells in the retina that produce nerve impulses?

Answer 1

retinal ganglion cells(projection neurons)

Question 2

what are the only cells that have projections that leave the eye?

Answer 2

retinal ganglion cells(projection neurons)

Question 3

what neurons process light?

Answer 3

internal nuclear cell layer

Question 4

what do amacrine cells and horizontal cells do?

Answer 4

talk with multiple streams of information and provide contrast in the visual field.
eg: being able to detect edges

Question 5

what do rods and cones do?

Answer 5

phototransduction, grated potentials

Question 6

what cell spans the retina and provides ion support and makes the virtuous humor? It is the only glial cell as well

Answer 6

muller supporting cell

Question 7

what cells are the only cells that us an action potential in the retina?

Answer 7

the retinal ganglion cells the rest use graded potentials

Question 8

what is the fovea used for?

Answer 8

high acuity vision, highest amount of cones are here

Question 9

where are rods located?

Answer 9

just outside the fovea

Question 10

what happens are the chiasm?

Answer 10

a partial decussation

Question 11

axons for temporal visual fields (lateral) do what at chiasm?

Answer 11

cross the contralateral

Question 12

axons for the nasal visual vision (medial) do what at chiasm?

Answer 12

remain ipsilateral

Question 13

the optic tract projects to what struction in the thalamus?

Answer 13

lateral geniculate nucleus (LGN)

Question 14

secondary neurons from the lateral geniculate nucleus go where?

Answer 14

to the primary visual cortex via optic radiations

Question 15

where is the superior field of vision located in the optic radiations?

Answer 15

in the temporal portion called the meyes loop

Question 16

where is the inferior field of vision located in the optic radiations?

Answer 16

in the parietal part

Question 17

what does pie in the sky mean?

Answer 17

damage to meyers loop will result in losing the superior vision

Question 18

primary visual cortex is divided into two portions, what are they?

Answer 18

lower field which is above the upper field

Question 19

what is the macula?

Answer 19

where high acuity vision goes

Question 20

what is the calcarine sulcus

Answer 20

what divides the lower and upper fields gyrus in the primary visual cortex

Question 21

the retinal is supplied by what artery?

Answer 21

ophthalmic artery

Question 22

the optic tract and lateral geniculate nucleus is supplied by what artery?

Answer 22

anterior choroidal artery(branch of middle cerebral)

Question 23

what parietal optic radiations are supplied by what artery?

Answer 23

middle cerebral

Question 24

the calcarine cortex is supplied by what artery?

Answer 24

posterior cerebral artery from the basilar artery

Question 25

in the pupillary light reflex the retinal ganglion cells send axons to what nucleus?

Answer 25

pretectal region

Question 26

axons from the pretectal region nucleus go where?

Answer 26

to the EW nucleus

Question 27

from the EW nucleus where do the parasympathetic axons go?

Answer 27

to the ciliary ganglion

Question 28

the nerve axons from the ciliary ganglion then go where?

Answer 28

to the pupillary constrictor muscles

Question 29

is the pupillary light reflex consensual?

Answer 29

yes

Question 30

subdural hematoma with uncal herniation symptoms

Answer 30

sluggish or absent pupillary reflex
ptosis
less effects on extraocular movements
CNIII effects

Question 31

pupillary dilation sympathetic pathway 1st step

Answer 31

hypothalamus sends signal to T1 sympathetics

Question 32

from the T1 level where does the sympathetic axon go?

Answer 32

to the superior cervical ganglion

Question 33

from the superior cervical ganglion where do the axons go?

Answer 33

to the pupil

tarsal muscle

Question 34

symptoms of horner’s syndrom

Answer 34

ptosis
miosis
anhyrosis
PAM has horns

Question 35

a lesion any where on the sympathetic pathway will lead to horner’s syndrome T/F?

Answer 35

true

Question 36

what does it mean that eyes are yoked?

Answer 36

move the same direction
controlled by centers in cortex and brainstem
no direct path from upper motor neurons to cranial nerves

Question 37

frontal eye fields do what?

Answer 37

voluntary fast horizontal eye movements of the opposite eye.

Question 38

what is the PPRF?

Answer 38

paramedian pontine reticular formation

Question 39

cells in the frontal eye field project to contralateral PPRF T/F

Answer 39

true

Question 40

where does the crossing occur ?

Answer 40

cuadal to nucleus III

Question 41

what does the PPRF do?

Answer 41

coordiates horizontal movements between CN III, IV, VI for both eyes

Question 42

from the PPRF where do axons go?

Answer 42

to the CN VI nucleus

Question 43

from CN VI where do the axons go?

Answer 43

to the lateral rectus and to CN III nucleus

Question 44

when axons from CN VI go the CN III nucleus what does it do?

Answer 44

synapses only on the medial rectus neurons

Question 45

PPRF lesions lead to horizontal gaze paralysis of both eyes, toward the side of the lesion or to the opposite side of lesion?

Answer 45

to the same side

Question 46

what is the MLF

Answer 46

the neuron going from CN VI nucleus to CN III nucleus

Question 47

a lesion of the MLF leads to what?

Answer 47

loss of adduction in ipsilateral eye.
diplopia(double vision)
typically a sign of MS
*other CN III functions are unaffected