PARASYMPATHETIC and OCULOSYMPATHETIC Flashcards
iris muscle - radial
dilate
Iris muscle - circumferrential
iris sphincter
fibers that terminates at the PTN in the midbrain
Pupillary fibers
fibers that terminate at the LGN of the thalamus
Visual fibers
pathway coming from receptors to CNS
Afferent parasympathetic pupillary pathway
pathway from CNS to effectors
efferent
Afferent parasympathetic pathway
Retina
Optic Nerve
Optic Chiasm
Optic Tract
PTN
Efferent parasympathetic pathway
EWN
CNIII
Pre-ganglionic fibers
Ciliary ganglion
Post-ganglionic fibers
Short ciliary nerve
Iris sphincter muscle
pupil characteristics observed
size
color
shape
speed of response
Visual pathway is also known as
retino-thalamocortical pathway
stimulates the pupillary sphincter muscle causing pupillary constriction
short ciliary nerves
2 decussations during pupillary light reflec
- Optic chiasm
- between the PTN and EWN
*light directed to left eye
Damage to left CNII
No direct and consensual
*light directed to left eye
Damage to optic chiasm
present both direct and consensual
*light directed to left eye
Damage to left CNIII
absent direct, present consensual
*light directed to left eye
Damage to left CNIII
present direct, absent consensual
Oculosympathetic pathway
hypothalamus
midbrain
spinal cord (C8, T1, T2)
ventral root of spinal cord
apex of lungs
cervical ganglion
carotid artery
ophthalmic branch of CNV
long ciliary nerve
dilator pupillae muscle
First-order neuron
posterolateral hypothalamus
passes through the midbrain
brainstem and intermediolateral column of spinal cord
exits at C8, T1, T2
second-order
ventral spinal root
arch over apex of lung
synapsing in the superior cervical ganglion
third-order
travels with carotid artery
cavernous sinus with ophthalmic branch of CNV
passes through ciliary ganglion
reaches eye as long ciliary nerve
Dilator pupillae muscle
comprised of axons of ganglions
optic nerve
