eye autonomics Flashcards
where does sympathetic innervation exit the spinal cord?
T1-L2 spinal nerves
where do pre synaptic axons from CNS exit the spinal cord and travel in the head and neck?
-they exit spinal cord in T1 spinal nerve then ascend within the sympathetic chain and synapse in superior cervical sympathetic ganglion
where do post synaptic sympathetic axons travel in head and neck?
- enter the internal and external carotid nerves
- pass onto the surface of the internal and external carotid arteries
- are carried to the organs of the head and neck on the surface of the branches of these arteries
- the ophthalmic artery carries the sympathetic axons into the orbit
where do all parasympathetic axons leave the CNS?
-via cranial nerves III, VII, IX and X via sacral spinal nerves
is the ciliary ganglion sympathetic or parasympathetic?
-parasympathetic ganglion
where is the ciliary ganglion located?
-in the bony orbit
which division of the Oculomotor nerve relates to the ciliary ganglion?
-inferior division
what does CNV1 sensory innervate in the face?
- upper eyelid
- cornea
- conjunctiva
which divisions of the trigeminal nerve are only sensory?
CNV1 and CNV2 (ophthalmic and maxillary)
what does CNV2 sensory innervate in the face?
- skin of the lower eyelid
- skin her maxilla
what does CNV3 innervate sensory of the face?
- skin over mandible and TMJ (temporomandibular joint)
- except angle of mandible
what nerve opens the eyelid?
oculomotor
what is the orbiculares oculi?
-muscle located on the eyelids
what is the most densely innervated part of the face?
cornea
role of corneal reflex?
-stop any irritants from entering the eye, protecting the cornea
what nerve is involved in the afferent (sensory) part of the corneal reflex?
CNV1 (ophthalmic division of trigeminal)
what nerve is involved in the efferent (motor) part of the corneal reflex?
CNVII (facial) (closes it)
what us the vestibulo ocular reflex?
- turns the eyes in the opposite direction to a head movement
- stabilises gaze on an object during head movement
what cranial nerves control the vestibulo ocular reflex?
CN VIII for vestibular part
CN III, IV and VI for move the eye
what is the oculocardiac reflex?
- reflex bradycardia in response to tension on extra ocular muscles or pressure on the eye
- basically pulling on the eye muscles can cause bradycardia, patients can get syncope from it
what encircle the pupil causing it to constrict when there is bright light?
sphincter papillae fibres which are around the circumference of the iris
is constriction of the pupil parasympathetic or sympathetic?
parasympathetic
-in bright light ‘rest and digest’
is dilation of the pupil sympathetic or parasympathetic?
-sympathetic
what fibres causes the pupil to dilate?
dilator papillae fibres
what’s a myadritic pupil?
-when myadriatic drugs induce dilation of the pupil
what’s a non physiologically constricted pupil called?
miotic pupil (this is a feature of Horner’s syndrome_
