ANS Pharm/Pupils

what are the 3 types of reflexes

near, light, corneal

when does the near reflex occur?

when looking at near objects

Is the near reflex a real reflex

no

when are the 3 occurrences of near reflexes 

convergence, accommodation, miosis 

what occurs during covergence

MR muscle contrats to maintain foveal fixation

what happens during accommodation

ciliary muscle contracts to increase focusing power of the eye

what happens during miosis (pupillary constriction)

spinchter muscle contracts to decrease size of pupil (improves DOF)

when does light reflex occur

when light is shown in one or both eyes

under normal circumstances, what happens to pupils under the light reflex

constricts

the light reflex does or does not require vision for the reflex to occur

does NOT

direct response of light reflex

constriction of ipsilateral pupil

consensual response of light reflex

constriction of the contralateral pupil

near vision requires what

visual cortex

what are ipRGC’s

intrinsically photosensitive retinal ganglion cells 

the ipRGC’s are image forming or non-image forming

non-image forming

afferent fibers are called what

pupillary fibers

what reflex follows part of the visual pathway

light reflex

afferent pathway of light reflex 

retina→ optic nerve (2)→ pretectal olivary nucleus

efferent pathway of the light reflex

edinger-westphal nucleus → oculomotor nerves→ ciliary ganglions→ short ciliary nerves→ iris spinchter muscles

which retinal fibers are crossed

nasal

which retinal fibers are uncrossed

temporal

if we have damage at the optic nerve, what happens to the eyes

neither eye will constrict

what is an example of damage to optic nerve

optic neuritis

In optic neuritis, the ipsilateral pretectal olivary nucleus innervates the

bilateral edinger-westphal nucleus

What does RAPD stand for

relative afferent pupillary defect

what is RAPD

afferent loops of the pupillary light reflex is impaired 

RAPD is a loss of what information

sensory

Where is the main cause of RAPD

optic nerve

both pupils constrict when light is directed at OD. Both pupils dilate when light is directed at OS. what type of RAPD is this

Severe

If damage occurs at the optic chiasm, what will the light reflex be?

normal

what is an example of optic chiasm damage

pituitary tumor

when there is no direct or consensual response in the pupil, the eye has what

No light perception (NLP)

near pupil reflex has

synchiensis