ANS & Pupils

iris, ciliary body, Muller muscle, lacrimal gland

what ocular structures are innervated by the ANS?

T1-T3 of the spine

where does the pre-ganglionic neurons of the SNS originate?

midbrain & pons

where does the pre-ganglionic neurons of the PSNS originate?

iris dilator, muller muscle, ciliary muscle, lacrimal gland

what ocular structures are innervated by the SNS?

iris sphincter, blood vessels, ciliary muscle, lacrimal gland

what ocular structures are innervated by the PSNS?

hypothalamus

sympathetic fibers are controlled by the _________

lacrimation, miosis, blink

what are the 3 parts to the corneal touch reflex?

V1 & CN7

which nerves are most important for the blinking aspect of the corneal touch reflex?

norepinephrine

what is the physiological agonist of the sympathetic nervous system?

acetylcholine

what is the physiological agonist of the parasympathetic nervous system?

epinephrine, phenylephrine

what are the 2 direct agonists for the sympathetic nervous system?

pilocarpine

what is the direct agonist for the parasympathetic nervous system?

hydroxyamphetamine, cocaine

what are the 2 indirect agonists for the sympathetic nervous system?

physostigmine

what is the indirect agonist for the parasympathetic nervous system?

dapiprazole

what is the direct antagonist for the sympathetic nervous system?

atropine, cyclopentolate, tropicamide

what are the 3 direct antagonists for the parasympathetic nervous system?

activated, inhibited

for maximal pupillary dilation, the dilator muscle must be ______ & the sphincter muscle must be ________

2.5% phenylephrine & 1% tropicamide

what drugs are commonly used in pupillary dilation?

relative afferent pupillary defect (RAPD)/Marcus Gunn pupil

• afferent pathway disorder

• direct & consensual responses are impaired

• pupil is not fixed

• lesion can occur anywhere in the afferent pathway but usually is at the optic nerve

• can use a swinging flashlight test to detect

Argyll Robertson Pupil

• midbrain pathway disorder

• lesion can involve pretectal nucleus, EW nucleus, or the fibers between those 2 structures

• accommodation response is present b/c FEF stay intact

• pupillary response is absent

• light near dissociation

• associated w/ diabetic neuropathy, alcoholic neuropathy, & neurosyphilis

Adie’s Tonic pupil

• efferent pathway disorder

• poor direct & consensual responses

• fixed pupil

• lesion is to ciliary ganglion or short ciliary nerve

• common in women aged 20-40yo

• 90% of pt also have diminished tendon reflexes

• affected pupil is larger in light & smaller in dark compared to normal pupil

• supersensitive sphincter

benign anisocoria

• difference in pupil sizes

• both pupils still dilate & respond well to light

Horner’s syndrome

• sympathetic pathway disorder

• ptosis, miosis, anhidrosis

• heterochromia if congenital

• good reaction to light but poor re-dilation in the dark

• lesion can be anywhere in the SNS pathway (hypothalamus, lungs, subclavian a., SCG, carotid dissection)

yes

if you administer cocaine 5% to a suspected Horner’s pupil and it does not dilate after 30-60min, does that pt have Horner’s?

no

if you administer cocaine 5% to a suspected Horner’s pupil & it does dilate w/in 30-60min, does that pt have Horner’s?

post-ganglionic (3rd order lesion)

if you administer hydroxyamphetamine 1% to Horner’s pt and they do not dilate after 15 minutes, this indicates the affected neuron is the ___________

pre-ganglionic (1st or 2nd order lesion)

if you administer hydroxyamphetamine 1% to Horner’s pt and they do dilate after 15 minutes, this indicates the affected neuron is the ___________