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56 Cards in this Set
- Front
- Back
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The eye is structurally divided into two chambers called?
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The vitreous (further divided into anterior and poster chambers) and aqueous chambers
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The wall of the eye is composed of what 3 layers?
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1. Sclera
2. Choroid 3. Retina |
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What is the name for the outer covering of the sclera?
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The conjunctiva
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What structures make up part of the middle layer through the clear cornea?
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The retina and pupil
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What are some characteristics of the lens?
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1. It is biconvex
2. Transparent 3. Elastic 4. Water and protein |
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What are the 3 layers of the lens?
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1. Capsule
2. Cortex 3. Nucleus |
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How does the lens allow for greater focusing of light on the retina?
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By changing its shape
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What are the main components of vitreous humor?
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Water and collagen
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Where is aqueous humor produced?
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In the posterior aqueous chamber by the ciliary body.
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Intraocular pressure is maintained by?
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Aqueous humor
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What is the name for a group of conditions in which the optic nerve is damaged, usually by an increase in intraocular pressure?
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Glaucoma. The angle of the anterior chamber is commonly shifted with glaucoma.
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More specifically, what produces aqueous humor?
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Ciliary processes
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What are the 3 parts of the ciliary body?
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1. Ciliary muscle
2. Ciliary processes 3. zonular fibers |
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Ciliary muscles are responsible for dilation of pupil by retraction of the iris via ciliary m. What innervates the ciliary m?
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Parasympathetic nerves
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What is the function of zonular fibers?
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Stabilizes the lens in position by attaching the lens periphery to ciliary muscles.
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What are the two optic parts of the retina?
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1. Pigmented layer - single cell layer attached to choroid beneath.
2. Neural layer - light sensitive and attached only to optic disc at periphery. |
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What is the blind spot?
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Space where the optic nerve pieces the sclera.
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The depression in the macular lutea that is the area of most acute vision is called?
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Fovea centralis
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What are the 3 branches of the ophthalmic artery that supply the eye?
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1. Short posterior ciliary artery
2. Long Posterior ciliary artery 3. Anterior ciliary artery |
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What artery pierces the optic nerve to supply most of the retina?
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Central retinal artery
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What supplies GA innervation to the cornea and sclera?
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V1 via long and short ciliary branches
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What supples VE parasympathetic innervation to the ciliary m and sphincter pupillae mm?
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Oculomotor (III)
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What supplies VE sympathetic innervation to the dilator pupillae m
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Internal carotid nerve plexus.
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Long ciliary branches to the eye from the nasociliary nerve provide what type of innervation to the eye?
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Sensory from V1 and sympathetic hitchhikers from carotid plexus. Short ciliary also provides sensory innervation from V1, but have autonomic fibers (para and sympathetic) too.
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What nerve going to the ciliary ganglion provides parasympathetic fibers?
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Oculomotor (III)
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Dilation of the pupil is controlled by what type of autonomics?
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sympathetic T1-2
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Constriction of the pupil and accomodation is controlled by what type of autonomics?
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Parasympathetics
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Preganglionic sympathetic fibers heading to the eye synapse in what ganglion? What about parasympathetic?
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Sympathetics synapse at superior cervical. Parasympathetics synapse at the ciliary ganglion
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Parasympathetics to the eye travel solely in what nerves?
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The short ciliary nn
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Define accommodation:
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Changing lens shape to focus light from nearby objects on the macula lutea and fovea centralis for acutve vision.
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Contraction of ciliary muscle under parasympathetic stimulation causes what to occur to the zonular fibers and lens?
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The zonular fibers will become relaxed and the lens will become wider.
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Dilator pupillae fibers run in what direction and are called?
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Radial fibers running longitudinally. Dilation under sympathetic control
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sphincter pupillae fibers fun in what direction and are called?
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Circumferential fibers running in concentric rings. Constrict the pupil under parasympathetic control
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When the ciliary body contracts, the lens becomes rounder and light is bent strongly, what type of vision is promoted (far/near)?
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Near vision. Increased radius of curvature
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Does myopia occur when the eyeball is too short or too long?
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When the eyeball is too long. Hyperopia is when the eyeball is too short.
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What is presbyopia?
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Inability for lens to accommodate due to stiffening. ie. reading books at arm's length
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Reflex miosis refers to what?
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Pupil constriction with light
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List the pathway of the corneal touch reflex?
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Afferent: [corneal touch] → short ciliary nn. → ciliary ganglion (no synapse) → nasociliary n. (V1) → opthalmic n. (V1) → semilunar ganglion → trigeminal n. → brainstem
Efferent: brainstem → facial nn. → temporal/zygomatic branches → orbicularuis occuli → [eye closes] |
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The medial palpebral ligament originates on what structure?
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The anterior lacrimal crest.
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Anesthesia of the lower eyelid is caused by a lesion to what nerve?
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V2
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What branches of the facial nerve supply the orbicularis oculi m?
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Temporal and zygomatic branches; lesion causes bell's palsy symptoms.
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What part of the eyelid is innervated by CN3?
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levator palpebrae superioris.
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VE sympathetics innervate what in the eyelid?
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Mueller's m. Injury can cause horner's syndrome (partial upper eyelid ptosis).
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The lacrimal apparatus is responsible for what?
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The production, movement and drainage of tears
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What nerve provides GA to the lacrimal apparatus?
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Lacrimal nerve V1 branch
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What is the parasympathetic innervation of the lacrimal apparatus?
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Secretomotor:
Preganglionics from the facial n (VII) travel in the greater petrosal n and n of the pterygoid canal to the pterygopalatine ganglion, where they synapse Postganglionics travel via the zygomatic n and communicating branch to the lacrimal n (V1) |
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What is the sympathetic innervation of the eye?
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May inhibit secretion of tears or change the viscosity of the tears
Preganglionics from T1-2 travel to the superior cervical ganglion, where they synapse. Postganglionics travel via the internal carotid n and plexus to the deep petrosal n and n of the pterygoid canal to the pterygopalatine ganglion They then follow the zygomatic n and communicating branch to the lacrimal n (V1) |
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A lesion to the facial nerve lesion proximal to the geniculate ganglion causes what?
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Complete loss of lacrimation, but conjunctival glands can sometimes make up for the loss via basal tears.
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Glaucoma is a group of conditions in which what nerve is ultimately damaged?
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Optic nerve via increased intraocular pressure.
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What layer of the eye does most vasculature of the eye run as well as GA nerves?
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Middle choroid layer
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The ciliary muscle is innervated by what type of nerve fibers?
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Parasympathetic. Via inferior division of oculomotor nerve to ciliary ganglion and from short ciliary nerves to ciliary m.
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The dilator pupillae m is innervated by what type of nerve fibers?
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sympathetic
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Venous drainage of the eye is done by which vessels?
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1. Central retinal vein (drains retina into superior ophthalmic vein)
2. Vorticose veins (4 large veins) - drain the rest of the eye into the superior and inferior ophthalmic veins |
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If the inferior division of the oculomotor nerve is damaged, what effect on function would this have?
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Inability to constrict the pupils due to loss of parasympathetic innervation of the constrictor pupillae m.
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VE fibers go to zygomatic nerve and through the communicating branch of zygomatic nerve to the lacrimal gland.
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...
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What causes papilledema?
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swelling of the optic nerve because of increased intracranial (CSF) pressure that compresses the central retinal vein and causes the retina to swell
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