Anatomy bits and pieces Flashcards
Describe the circulation of aquous humor
- Produced at the ciliary body in the posterior chamber
- Passes through posterior chamber and nourishes the lens
- Passes through the pupil into the anterior chamber where it nourishes the cornea
- Drains in the canal of schlemm or the scleral venous sinus at the iridoscorneal angle
Why is the iridocorneal angle significant in terms of aqueous humor?
Tight angle can cause acute closed angle glaucoma in which aquous fluid cannot drain
Which nerve is found at the optic disc?
CN II Optic nerve
The macula contains the greatest density of?
Cones
What are the 3 layers of the retina?
Innermost - photoreceptors
- ganglion cells
- axons of the ganglion cells
V1 provides sensory supply to?
upper eyelid
cornea
conjunctiva
skin of the root/bridge/tip of the nose
V2 provides sensory supply to?
skin of the lower eyelid
skin over the maxilla
skin of the ala of the nose
skin/mucosa of the upper lip
V3 provides sensory supply to?
skin over the mandible and temporomandibular joint
apart from the angle of the mandible – supplied by C2,3 spinal nerves
Describe the corneal reflex
Also known as blink reflex
Afferent nerve is receptor from the long ciliary nerve to V1 to trigemenal ganglion and synapse with facial nerve in CNS
Efferent nerve is facial nerve to eyelid part of orbicularis oculi
What is the route of sympathetic nerves in the body
exit between T1 - L2 to sympathetic chain then to splanchic nerves to supply organs
Where do all parasympathetic nerves leave the body?
cranial nerves III, VII, IX & X and via sacral spinal nerves
Describe the cervical part of the sympathetic trunk
Fibres exit via T1
Ascend and synapse with superior cervical ganglion
Post synaptic fibres enter internal and external carotid nerves which pass over the internal and external carotid arteries
Inernal becomes opthalmic artery which carries sympathetic fibres to the eye on it
Describe the route of CNIII from the brain to the eye
Passes through cavernous sinus
Exits via superior orbital fissue
Provides somatic motor to muscles of eye
Provides presynaptic parasympathetic supply via the ciliary ganglion
What is the vestibuloocular reflex?
turns the eyes in the opposite direction to a head movement
stabilises gaze on an object during head movement
CNS connections between CN VIII & CNs
III, IV & VI
What is the cardioocular reflex?
reflex bradycardia in response to tension on extraocular muscles or pressure on eye
CNS connections between CN V1 & CN X
