Visual Reflexes

Question 1

Where should light be shown for the pupillary reflex

Answer 1

temporal retina

Question 2

What is the afferent path of both the direct and consensual pupillary reflex

Answer 2

Optic nerve
Optic tract
Optic chiasm
Pass thru LGB
Superior brachium to pretectal nucles

Question 3

Path of efferent of direct pupillary reflex

Answer 3

Pretectal nucleus into IL edinger westphal nucleus–> pre ganglipnic parasymathetic axons leave and exit midbrain and incorporate into occulomotor nerve–> target cillary ganglion. Post ganglionic parasymethetic that leave cillary contribuite to short cillary nerves that supply contrictor papilae mm

Question 4

Path of effernt connsenual pulillary reflex

Answer 4

Pretectal nucleus into CL edinger westphal nucleus thru post commisure–> pre ganglipnic parasymathetic axons leave and exit midbrain and incorporate into occulomotor nerve–> target cillary ganglion. Post ganglionic parasymethetic that leave cillary contribuite to short cillary nerves that supply contrictor papilae mm

Question 5

No light on retina leads to what

Answer 5

ivoluntary iridodialation

Question 6

Path of afferent dim light response

Answer 6

No signal to pretectal nuc
Collateral project to reticular formation into hypothalamic nuclei, projecting bilaterally into interomediolat column of spinal cord t1-3 (Sympathetic centers)

Question 7

Efferent path of dim ligt response

Answer 7

Exit ventral horn and pass thru white commicans to travel thru sympathetic trunk to sup cervical ganglia.

Post ganglionic symp fibres follow periarterial nerve plexus/int corotid plexis contributing to short+long cillary nerves to dialator mm

Question 8

What are the 3 things that occur in the accommodation reflex

Answer 8

1. Occular convergence
2. Thickening of lens
3. Iridoconstriction

Question 9

Afferent path of occular convergence

Answer 9

Retina signals thru optic nerve/chiasma/tract (some cross normally), projects into lgb, optic radiations into visual cortex, then travel to frontal eye field

Question 10

Efferent path of occular convergence

Answer 10

Descending corticomesencephaluc fibres from frontal eyefield bilaterally proect into occulomotor nucleus targeting medial rectus subgroup (turn eyes in)

Question 11

Afferent path of lens thickening

Answer 11

Retina-> optic nerve to chiasm, tract, pass LGB. Superior brachium to pretectal nucleus (right and left side)

Question 12

Efferent path of lens thickening

Answer 12

Axons from pretectal to BL edinger westphal (IL and CL, pass thru post commisure), pre ganglionic fibres go thru occulomotor n and reach cilliary ganglion. Post ympathetic fibres for m short cillary nerves and enter cillary mm (lens becomes thicker)

Question 13

What is argyll roberston pupil/light near dissociation and what is it due to

Answer 13

can accomodate pupils(constrict+converge) but do not react directly to light

• lesion in pretectal zone of rostral midbrain
• teriary syphilis

Question 14

Presentation of argyll roberston pupil/light near dissociation

Answer 14

Small pupils

Question 15

Presentation of adies pupil/light near dissociation

Answer 15

Large pupils

Question 16

Effect of adies pupil/light near dissociation

Answer 16

• pupillary light reflex absent/ present but slow

- Accommodation to near vision present + fast

Question 17

What is adies pupil/light near dissociation due to

Answer 17

lesion in the cillary ganglion

Question 18

What occurs in horners syndrome (3)

Answer 18

1. iridoconstriction
2. Droopy sup eyelid
3. absencet or decreased facial sweating

Question 19

What can horners syndrome be due to (central + peripheral)

Answer 19

Central- lat medullary syndrome (PICA), Spyringomyelia (T1/2)

Peripheral lesion- neck tumor, carotid aneurism affecting cervical sympathetic chan/sup cervical ganglion