Ocular Anatomy Flashcards
lines the inner aspect of the eyelids
Palpebral conjunctiva
Thin, transparent vascular tissue that extends from the limbusto the mucocutaneousjunction of the eyelid
Conjunctiva
covers the sclera
Bulbar conjunctiva
Conjunctiva artery
anterior ciliary artery
Conjunctiva inervated by
CN V (ophthalmic division
Fine, thin, elastic layer which covers the sclera
Underneath the conjunctiva
Contains numerous blood vessels –> provide nourishment for the sclera
Episclera
Thick outer coat of the eye
Normally white and opaque
Avascular& fibrous (collagen)
Continuous with the cornea anteriorlyand with the dural sheath of the optic nerve posteriorly
Sclera
Transparent front “window”of the eye
Refracts light
Cornea
nonkeratinized stratified squamousepithelium, regenerative ability
Corneal epithelium
collagen fibers
Bowmans layer
thick layer (90%) of regularly arranged collagen fibers (type 1), keratinocytes
Corneal stroma
thin, strong layer, discovered in 2013
Dua’s layer
thin acellularlayer that serves as the modified basement membrane of the endothelium, collage type IV
Descemet’s membrane
monolayer of cuboidalcells, not able to regenerate, responsible for the corne’sdeturgescence
Endothelium
The junction between cornea and sclera
Limbus
Limbus May develop whitening as part of old age
Arcus senilis
The space between the cornea and iris
Anterior chamber
Anterior chamber Contains a watery fluid called
Aqueous humor
Angle formed by the inner cornea and iris roots
Comprised of several structures that make up the eye’s drainage system
Anterior chamber angle
eye’s drainage system
trabecularmeshwork
Schlemm’scanal
middle, vascular layer of the eye
Uveal tract
Colored part of the eye that controls the amount of light that enters the eye
Iris
hole at the center of the iris that, size is controlled by the iris muscles
Pupil
Accounts for the variety of eye colors seen
Dependent on the amount of pigment in the iris
Pigmented posterior surface of the iris
contains both dilator and sphincter muscles
Iris stroma
Contraction of the sphincter muscle
Pupil constriction
Contraction of the dilator muscles
Pupil dilation
Blood supply of the iris
Major circle of the iris
Sensory inervation of the iris
ciliary nerves
Circular opening at the center of the iris
Adjusts the amount of light entering the eye
Pupil
Pupil constriction
parasympathetic activity –CN III
Pupil dilation due to
Sympatethetic activity
Structure of the eye that produces aqueous humor
Ciliary body
Contraction of the ciliarybodyChanges the tension of the
Zonular fibers
Ciliary body Change in tension leads to increased thickness of the lens allows eye to focus at near objects
Accomodation
Vascular, pigmented layer between the sclera(externally) and the retina (internally)
Provides blood supply to the outer retinal layers
Choroid
Biconvex structureRefracts and focuses light on the retina
Crystaline lens
Crystalline lens Suspended in place by
Zonula fibers
Crystalline lens anteroposterior
4.0 to 5.0 mm
Crystalline lens equatorial diameter
9.0 to 10mm
narrow space behind the iris and in front of the zonulefibers Space anterior to the crystalline lens
Filled with aqueous humor
Normally acellular
Posterior chamber
Large space behind the lens
Extends up to the retina
Approximately 4.5 cc in volume
Vitreous cavity
Vitreous cavity Filled with a transparent gel-like material called
Vitreous humor
Thin, semitransparent, multilayer sheet of neural tissue lining the vitreous cavity
Retina
10 layers of retina
- Retinal pigment epithelium
- Photoreceptor
- Outer limiting membrane
- Outer nuclear layer
- Outer plexiformlayer
- Inner nuclear layer
- Inner plexiformlayer
- Ganglion cell layer
- Retinal nerve fiber layer
- Inner limiting membrane
Retina blood supply
Central retinal artery
Branch of the ophthalmic artery
supplies inner 1/3 of the retina
Choroid
Supplied by the ophthalmic artery
Supplies outer 2/3 of the retina
Area of the retina responsible for fine, central vision
Macula
oval depression in the center of the macula
Approximately 2 disc diameters away from the optic disc
Slight inferior to the optic disc
Fovea
not really a peripheral nerve, it is actually a direct extension of the CNS 1.2 M axons 50 mm long Synapses at the lateral geniculatenucleus
Optic nerve
Blood supply of optic nerve
Circle of zinn-haller
Short PCA
Choroidalcirculation
Pialvasculature