Eye Reflex Pathways Flashcards
What is efferent limb for reflex tears?
CNVII
How do sympathetics get from chain to eye?
Exit spinal cord at T1, ascend within sympathetic trunk, synapse at superior cervical ganglion.
Post-synaptic neurones enter carotid nerves then surface of carotid arteries. Piggy back ophthalmic artery to the orbit
Other name for parasympathetic outflow?
Craniosacral outflow
Where do eye sympathetics synapse?
superior cervical ganglion
Three things that happens in the accommodation reflex (response to near)
Pupil constriction Cross eyed (medial) Lens becomes fat
What is Miosis?
Constriction of one pupil
What type of signals synapse at the ciliary ganglion?
Only parasympathetics
Name the four important steps/areas in pupillary reflexes (not to do with specific nerves)
Retinal ganglion cells to pretectal nucleus;
Pretectal nucelus to Edinger Westphal nucleus;
EW nucleus to ciliary ganglion;
Ciliary ganglion to sphincter pupillae muscles;
Where does CNIII exit the skull to provide for the eye muscles?
Superior orbital fissure
What are reflex tears?
Extra tears on top of basal ones in response to chemical or mechanical stimuli
What is a non-physiologically enlarged pupil called?
Mydriatic pupil
In blinking reflex, what is the efferent nerve?
CNVII
In the blinking reflex, what muscle is stimulated and by what nerve?
Eyelid part of orbicularis oculi, CNVII
Where do CNVII parasympathetic fibres synapse?
Pterygopalatine ganglion to provide for lacrimal gland
Muscle for pupil constriction and what type of control it is under
Sphincter pupillae, parasympathetic
