Anatomy - Eye Autonomics Flashcards
what is the sensory nerve of the face collectively known as?
trigeminal nerve (CNV) 3 parts
what are the 3 parts of the trigeminal nerve?
ophthalmic nerve (V1) maxillary nerve (V2) mandibular nerve (V3)
what does ophthalmic nerve supply?
upper eyelid
cornea
conjunctiva
skin of root/bridge/tip of nose
what does the maxillary nerve supply?
skin of lower eyelid
skin over maxilla
skin of the ala of the nose
skin/mucosa of the upper lip
what does the mandibular nerve supply?
skin over the mandible and TMJ
what is the only area of the face not supplied by the trigeminal nerve?
jaw line
supplied by C2 and C3 spinal nerves
describe the steps in the blink reflex
sensory (afferent limb):
- action potentials are conducted from the cornea via CNV1 branches
- action potentials travel to trigeminal ganglion then along CNV to the Pons
central CNS connections between CNV and CNVII (facial nerve)
motor efferent limb:
- action potentials conducted via CN VII (facial nerve) to eyelid part of orbicularis oculi
describe the route of sympathetic axons
originate from autonomic centres in the brain
pass down spinal cord
exit spinal cord with T1-L2 spinal nerves (thoracolumbar outflow)
travel to sympathetic chains running down the length of the vertebral column
pass into all spinal nerves (anterior and posterior rami)
pass into splanchnic nerves to eventually supply organs
how does the eye differ?
uses cervical ganglia instead of splanchnic nerves
superior and inferior cervical ganglia relay sympathetic info
describe how sympathetic nerves reach the eye
presynaptic sympathetic axons from the CNS exit spinal cord in T1 spinal nerve and ascend within the synaptic trunk
axons synapse in the superior cervical sympathetic ganglion
post-synaptic sympathetic axons enter internal and external carotid nerves and pass onto the surface of the internal and external carotid arteries - forming peri-arterial sympathetic plexus
these nerves are then carried to the organs of the head on the surface of the branches of these arteries
ophthalmic artery carries sympathetic axons into the orbit
the ophthalmic artery is a terminal branch of which artery?
internal carotid
all parasympathetic axons leave the CNS via which nerves?
cranial nerves - III, VII, IX and X sacral spinal nerves
= craniosacral outflow
how does parasympathetic info from CN III reach the eye and what does it do?
presynaptic fibres synapse at the ciliary ganglion and post synaptic fibres travel to the eye
change shape of eye and iris
what do the parasympathetic ganglia in the head supply?
eye
lacrimal gland
salivary glands
what does the vagus nerve supply?
organs of the neck, chest, abdomen as far as the mid-gut
what do sacral spinal nerves do?
carry parasympathetic axons to the hindgut, pelvis and perineum
what is CN III also known as?
oculomotor
where is CN III found?
connects with the CNS at junction between midline and pons
describe the course of CN III
connects with the CNS at junction between midline and pons
passes through cavernous sinus
exits via superior orbital fissure
what does CNIII supply somatic motor to?
somatic motor to superior, medial and inferior rectus and inferior oblique
levator palpebrae superioris
where does CN III supply presynaptic parasympathetic ganglions to?
ciliary ganglion
what are the ciliary nerves?
supply autonomic axons to control diameter of iris and refractive shape of lens