Pupillary Reflexes Flashcards
What are the different pupillary reflexes?
Light reflex
Accommodation reflex
What stimulates the light reflex?
Light hitting the retina
What is the afferent branch of the light reflex?
CN2 optic nerve
What does the CN2 optic nerve do in the brain, in the light reflex?
Gives off branches
These synapse with neurones in the pre-tectal area of the midbrain
What do neurones arising from the pre-tectal area of the midbrain do, in the light reflex?
Synapse in Edinger-Westphal nucleus on both sides
With parasympathetic fibres in the CN3 oculomotor nerve
What do parasympathetic fibres in the CN3 oculomotor nerve do, in the light reflex?
Stimulate the constrictor pupillae muscle which constricts the pupil
What can the light reflex be divided into?
Direct light reflex
Consensual light reflex
What is the direct light reflex?
Shining light in one eye makes the ipsilateral pupil constrict
What is the consensual light reflex?
Shining light in one eye makes the contralateral pupil constrict
What stimulates the accommodation reflex?
Object coming closer to the eye
This visual information is carried to and interpreted in the primary visual cortex
What do neurones arising from the primary visual cortex in the occipital lobe do, in the accommodation reflex?
Synapse with neurones in pre-tectal area of midbrain
What do neurones arising from the pre-tectal area of the midbrain do, in the accommodation reflex?
Synapse in Edinger-Westphal nucleus on both sides
With parasympathetic and motor fibres of CN3 oculomotor nerve
What do parasympathetic fibres in the CN3 oculomotor nerve do, in the accommodation reflex?
Stimulate the constrictor pupillae muscle which constricts the pupil
Stimulate the ciliary muscle which increases the thickness of the lens
What do motor fibres in the CN3 oculomotor nerve do, in the accommodation reflex?
Stimulate medial rectus muscle which adducts the eye
