REFLEXES OF THE EYE - MODULE Flashcards
What reflex allows for the adjustment of changing light conditions
the pupillary light reflex
What muscle is responsible for constriction of the pupil?
constrictor pupillae
what nervous system leads to pupil constriction
parasympathetic
in the pupillary light reflex, light reaches the retina and informations travels via the optic nerve to the …
pretectal nuclei in the midbrain
in the pupillary light reflex, fibres from each pretectal nucleus sends bilateral projections to the
edinger-westphal nuclei
in the pupillary light reflex, preganglionic parasympathetic fibers from the edinger-westphal nuclei travel with the oculomotor nerve to the…
ciliary ganglia
what is the final step to the pupillary light reflex
postganglionic parasympathetic fibres travels as the short ciliary nerves and innervate the contrictor pupillae muscles
if the right CN III is damaged, shining light in the right eye will result in
no constriction of right pupil but constriction of left pupil
The pupillodilator reflex relies on what nervous system
the sympathetic
When is the pupillodilator reflex activated
in response to strong emotional state
what muscle is responsible for he pupillodilator relfex
the dilator pupillae muscle
What initiates the pupillodilator reflex
sympathetic neurons in the lateral horn of spinal segment T1 are stimulated by higher brain systems in response to emotional stimulus
in the pupillodilator reflex, sympathetic fibres leave the spinal cord and travel up the sympathetic trunk to the…
superior cervical ganglion
in the pupillodilator reflex, postganglionic fibres travel along the _____ into the cranium
carotid artery
in the in the pupillodilator reflex, once in the cranium the postganglionic fibres travel to the orbit along the…
ophthalmic division of the trigeminal nerve
in the pupillodilator reflex, the fibres branch off V1 as the ___ and innervate the dilator pupillae muscles of the iris
long cilary nerves
What is the pathway called that causes blinking of the eye when the eye senses touch or pain
corneal bink relfex
in the corneal blink reflex, following sensory stimuli to the cornea, sensory afferent travel via the _______ to the _____
ophthalmic division of the trigeminal nerve to the trigeminal sensory nucleus
in the corneal blink reflex, sensory afferents synapse with spinal trigeminal interneurons, which project to the
facial motor nucleus
in the corneal blink reflex, fibres from the facial motor nucleis innervate the
circular orbicularis oculi muscles
Convergence and divergence of the eyes is caused by signal from the
vergence centers
where are the vergence centers located
in the rostral midbrain
the vergence centres signal the ____ causing convergence
oculomotor nuclei
the vergence centres signal the ____ causing divergence
abducens nuclei
In order to focus on a near object what 3 things must occur
- convergence of the eyes
- thickening of the lens
- constriction of the pupil
What area of the brain coordinates the 3 things that must occur in order to focus on something near
the supraoculomotor area in the rostral midbrain
In the accommodation reflex, the supraoculomotor area sends bilateral projections to the _____ and the _____
oculomotor nucleus and the edinger-Westphal nuclei
in the accommodation relfex, innervation of the oculomotor nuclei results in ____
convergence of the eyes via the activation of the medial rectus muscle
in the accommodation relfex, innervation of the edinger-Westphal nuclei results in ____
parasympathetic innervation of the constricor pupillae muscles resulting in constriction of the eyes
Int he accommodation reflex, what causes the lens to change shape and increase curvature
parasympathetic stimulation of the ciliary muscles
