Important Reflexes of the Orbital Region Flashcards
what parts of the eye does the opthalmic nerve (CNV1) supply?
upper eyelid
cornea
conjunctiva
what parts of the eye does the maxillary nerve (CNV2) supply?
lower eyelid
sensory nerve to the face?
trigeminal
only part of the face not to be supplied by the trigeminal nerve?
spinal nerves C2 + 3
describe the route a sensory afferent takes when you need to blink
from cornea to CNV1 branch
goes via trigeminal ganglion to pons
describe the route a motor efferent takes when you need to blink
action potentials conducted by CN 7
go to eyelid part of orbicularis oculi
how do sympathetic nerves of the eyes reach them?
exit at T1 of the symp chain
head up the chain alongside carotid arteries
synapses at the superior cervical ganglia
carried to the orbit by opthalmic artery
parasympathetic axons supply the body: T or F
F
what foramen does cn 3 exit via?
superior orbital fissure
what do the ciliary nerves do?
control diameter of iris
control refractive shape of lens
most important cranial nerve for parasympathetic innervation of the eye?
CN3
CN7 is also important
what makes up the short ciliary nerve?
inferior division of CN3
what makes up the long ciliary nerve?
CNV1
what type of ciliary nerve is responsible for parasympathetic innervation of the eye
short
what is the name of the reflex that causes you to blink when something is coming close to you?
accommodation reflex
what is the vestibulo-ochlear reflex?
eyes turn an opposite way to the head to focus on an object
which autonomic type allows the eye to focus on far objects and which allows you to focus on near objects?
near= parasympathetic far= sympathetic
which autonomic nerves are responsible for reflex lacrimation?
parasympathetic
what controls smooth muscle?
autonomic nervous system
how is the sympathetic nervous system able to open the eyes wider even if you dont want them to?
there is smooth as well as skeletal muscle in the levator palpebrae superioris
name the muscle and autonomic nerves responsible for pupillary dilatation
dilator pupillae muscles
sympathetic
what is a mydriatic pupil?
a non-physiologically enlarged pupil
where do the dilator pupillae muscles attach?
around the iris circumference
what nerves control pupillary constriction
parasympathetics
cause of a fixed pin point pupil?
opiate drugs
cause of a fixed dilated pupil?
cn3 pathology
what nerves control the sensory and motor part of the pupil light reflex?
sensory= optic motor= oculomotor
what happens to the other eye when light is shone in one eye?
it should constrict
why do pupils constrict when exposed to light?
to stop excess light damaging the retina
how many neurones are in the pupillary light reflex chain?
4
name the synaptic locations of each of the neurones of the pupillary light reflex chain
- pretectal nucleus in midbrain
- EW nucleus
- ciliary ganglion
what is the ciliary body?
a sphincter controlling the lens of the eye
the ciliary muscle is not innervated by any parasympatheitc nerves: T or F
F
does the ciliary muscle contract in near or far vision?
near
what nerves cause the relaxation of the lens?
sympathetic
what nerves cause the contraction of the lens?
parasympathetic
what happens to eyesight when the lens is contracted?
focuses on far sight
how are tears antimicrobial?
contain lysozyme that hydrolyses bacterial cell walls
afferent and efferent limbs of the lacrimal reflex?
CNV1 from cornea= afferent
parasympathetics from CN7= efferent
symptoms of horners syndrome?
miosis ptosis reduced sweating increased warmth redness
