Anatomy (2) Flashcards
(20 cards)
What bones make up the orbit? (7)
Frontal, Maxillary, Zygomatic, Sphenoid, Ethmoid, Palatine, Lacrimal
Where are tears produced and drained?
Lacrimal gland (superiolateral) Nasolacrimal duct (medial)
What are the 2 types of conjunctiva and where are they?
Bulbar conjunctiva: lines the eye
Tarsal conjunctiva: lines the inner eyelid
What is in the outer layer of the eye?
Sclera + cornea
What is in the middle layer of the eye?
Choroid + ciliary body (vascular layer)
What is in the inner layer of the eye?
Retina
What suspends the lens and what muscles control these?
Suspensory ligaments (ciliary muscles)
What ocular muscles are supplied by CNIII?
Medial rectus, Superior rectus, Inferior rectus, Inferior oblique, Levator palpebrae superioris (LPS)
What is the action of the superior and inferior obliques?
Superior = in and down Inferior = in and up
What is the nerve supply of levator palpebrae superioris?
CNIII + sympathetic (autonomic)
What are the 3 intraocular muscles and what is their nerve supply?
Ciliary muscles (parasympathetic via CNIII ciliary ganglion) Sphincter pupillae (parasympathetic via CNIII ciliary ganglion)
Dilator pupillae (sympathetic via internal carotid plexus)
What would occur if there was palsy of CNIII, CNIV, CNVI?
CNIII: fixed down and out
CNIV: NO in + down
CNVI: NO out (lateral)
What provides sensory innervation of the eye?
Somatic = CNV1 (ophthalmic) Special = CNII (optic)
What occurs during accommodation and what nerve is responsible for this?
Rounding of the lens to focus from far to near = contraction of ciliary body
CNIII parasympathetic via ciliary ganglion
What occurs during the light reflex and what nerves are responsible for this?
Constriction in response to light stimuli
Afferent = CNII, efferent = CNIII (sphincter pupillae)
What occurs during the corneal reflex and what nerves are responsible?
Blink in response to a physical stimuli
Afferent = CNV1, efferent = CNVII (orbicularis oris)
What is the nerve supply to orbicularis oris and what is its function?
CNVII (facial)
Voluntary + parasympathetic
Blinking (voluntary or reflex)
Where does the blood supply to the eye originate and what is its terminal branch?
Internal carotid
Ophthalmic artery (branches to form posterior ciliary arteries)
Central retinal artery
What are the 2 types of humour in the eye and what is their production?
Vitreous humour (posterior segment - never replaced) Aqueous humous (anterior segment - constantly produced)
Describe the route of anterior humour?
Produced in the ciliary body
Nourishes the lens in the posterior chamber
Nourishes the cornea in the anterior chamber
Reabsorbed through the iridocorneal angle (canal of schlemm)
