Nerves & Pupils Flashcards
Which of preganglionic vs. postganglionic neurons in the ANS is usually myelinated?
preganglionic (first motor neuron)
What type of ANS innervation dilates the pupil?
Sympathetic
What type of ANS innervation constricts the pupil?
Parasympathetic
What type of ANS innervation allows accommodation to occur?
Parasympathetic (some inhibitory sympathetic)
What type of ANS innervation allows Muller’s muscle to open eyelids wide?
Sympathetic
Which levels of the spinal cord have sympathetic outputs that go to the head/neck and what is this location on the spinal cord called?
Levels T1-T5 (mostly T1-T3) where sympathetic preganglionic fibers leave CNS at the ciliospinal center of Budge (intermediolateral horn) to then synapse in the cervical ganglia
How does the postganglionic neuron of the sympathetic innervation to the eye travel?
Follows the internal carotid artery into the cavernous sinus, then may travel with CNIII to the Superior Tarsal Muscle (Mullers) or with V1 through nasociliary and long ciliary nerves to reach the iris dilator and the ciliary muscle
(other similar pathways to reach the blood vessels of eye for sympathetic innervation)
What is the Horner’s syndrome triad?
ptosis, miosis, anhidrosis
Which type of innervation is affected by Horner’s syndrome?
Horner’s affects the sympathetic innervation to the eye (head and neck also) and can be congenital or acquired (possible sign of tumors, aneurysms, damage to ICA, or CNS problems)
Which cranial nerve carries sensory information from ocular structures (and face)?
CNV - trigeminal nerve
Which are the cranial nerves that innervate the extraocular muscles and which one does which?
CNIII - oculomotor: SR, MR, IR, IO, (LPS)
CNIV - trochlear: SO
CNVI - abducens: LR
What are the three big branches of the trigeminal nerve and what are the foramina or spaces they travel through?
V1 - ophthalmic nerve travels through the supraorbital fissure, V2 - maxillary nerve travels through the foramen rotundum, and V3 - mandibular nerve which travels through the foramen ovale
T/F: the trigeminal ganglion is a location of sensory cell bodies (pseudounipolar cells)
True
What are the three branches of the ophthalmic nerve?
Nasociliary, Frontal, Lacrimal
What are the five branches of the nasociliary nerve?
Infratrochlear, anterior ethmoid, posterior ethmoid, long ciliary nerves, and the sensory root to the ciliary ganglion (which gives off short ciliary nerves)
Which nerve carries sensory information from the medial canthal area of the eyelid
Infratrochlear (travels below trochlea to front of eye, along the upper border of the medial rectus)
What areas do the ethmoid nerves innervate?
the sensory skin along center of nose, nasal mucosa, ethmoid sinuses, and sphenoid sinus (posterior)
travel through foramina with arteries of the same name
What are the areas and types of innervation that are controlled by the long ciliary nerves?
Sensory of the cornea, and carries sympathetic motor to the iris dilator
(there are 2 nerves, one medial and one lateral and they travel between the choroid and sclera)