Eye Flashcards
Major structures of the eye
palpebrae
eye lol
bony orbit
Palpebrae structures
muscles
tarsal plates (contain meibomian glands)
palpebral conjunctiva
lacrimal apparatus
muscles on the palpebrae
orbicularis oculi
levator palpebrae superioris
orbicularis oculi muscle
surrounds orbit
allows for squinting/blinking
***innervated by facial nerve
levator palpebrae superioris
*no inferiorus
attaches to tarsal plate and assists in further retracting upper eyelid
considered an extra ocular muscle of the eye duct
meibomian gland
oil glands along most distal part of palpebrae
produce oily substance that slows evaporation of lacrimal secretions
lacrimal apparatus
lacrimal gland lacrimal papilla lacrimal canaliculus lacrimal sac nasolacrimal duct
flow of lacrimal secretions
lacrimal gland –> lacrimal papilla –> lacrimal canaliculus –> lacrimal sac –> nasolacrimal duct –> inferior nasal meatus
inflammation of the lacrimal sac
dacryocystitis
Palpebral conjunctiva is
mucous membrane of the eye
continuous with bulbar conjunctiva
Structures of the eyeball
cornea conjunctiva sclera iris/pupil lens retina chambers (3)
light focusing apparatus
cornea iris lens ciliary body/muscle anterior/posterior chambers
light sensing apparatus
vitreous body
retina
choroid
optic nerve
what flows through the anterior and posterior chambers
aqueous humor – provides nutrients to structures there
what are anterior and posterior chambers separated by
iris
cornea
outermost layer of the anterior eye
not covered in conjunctiva
protects inner eye structures
bends light to focus it into iris/pupil/lens (refraction)
iris/pupil
muscular pigmented ring that separates anterior/posterior chambers of eye
pupil = hole in the middle
muscles on the iris/pupil
sphincter pupillae muscle = constricts pupil
dilator pupillae muscle = dilates pupil
light receptor activation in either eye will trigger bilateral pupillary constriction
light –> retinal photoreceptors –> Edinger-Westphal nucleus –> ciliary ganglion –> sphincter pupillae
lens is composed primarily of
proteins called cristallins
composed of living cells
primary function of lens
focus light onto fovea/macula of retina
lens is suspended in the eye by
the ciliary muscle
allows for changes in focus by stretching the lens altering its refractive properties
refraction of near and distant objects
near object - strong refraction
distant object - weak refraction
aqueous humor
provides support for structures of the focusing apparatus of the eye
provides nutrients to these structures
created by ciliary body
primary light sensing structure
retina
retina is covered with _____ separated into 2 groups:
covered with photoreceptors; separated into rods and cones
Rods
sense light, no color, poor spatial acuity
cones
sense light + color, good spatial acuity
Vitreous body
clear gel filled capsule in the posterior eye (does not refract light)
provides structure to the eye and reduces risk of retinal detachment
Layers of the posterior eye
outermost: sclera
middle: choroid
innermost: retina
Sclera
structural protective layer of posterior eye
choroid
vascular layer that supports the retina
contains pigments to reduce reflection of light
retina
key layer for photoreception
receives light and converts it to electrical impulses
retina innervation
optic nerve (CN2)
structures of the retina
optic disc (where optic nerve enters)
macula – fovea
Retinal artery/vein
inactive ocular toxoplasmosis
scar tissue build up
minimal to no vision deficits
recurrence is common bc it is a parasite?
What is the arterial to venous ratio normally
2:3
Macular degeneration
white drusen of the retina indicate mottling/macular degeneration
Papilledema
blurred disc margins
central retinal vein occlusion
disc is virtually obscured by edema and hemorrhages
central retinal artery occlusion
cherry red fovea
pale retina
significant attenuation of vasculature
Hypertensive retinopathy
retina displays exudates and flame hemorrhage
orbit
bony cavern of face which protects eyes
separated by nasal cavity/sinuses
7 bones
orbit innervation/vasculature
more concentrated innervation/vasculature than almost any other location of the body outside the brain
(trauma is problematic)
Bones of the orbit
sphenoid frontal zygomatic ethmoid lacrimal maxilla palatine
eye is surrounded by supportive fat pads that protect structures from bony orbit
adipose body of the orbit (ABO)
ABO lost with age
enophthalmos
orbit blood supply
internal carotid artery ophthalmic artery central retinal artery lacrimal artery posterior ciliary arteries supraorbital artery anterior/posterior ethmoidal arteries supratrochlear artery dorsal nasal artery
Venous drainage of orbit
superior ophthalmic vein and inferior ophthalmic vein drain into cavernous sinus
extra ocular muscles of the orbit
superior rectus medial rectus inferior rectus lateral rectus superior oblique inferior oblique levator palpebrae superioris
Extraocular muscles innervation
CN3 oculomotor
CN4 trochlear
CN6 abducens
LR6-SO4-R3
