eye anatomy Flashcards
what are the 3 main parts of the eye
sclera
retina
uvea
where does the optic nerve develop from
optic cup of the embryonic diencephalon
adnexa
supporting structures surrounding the eyeball
what are the eye compartments
aqueous humour - rostral
vitreous humour - caudal
features of aqueous humour
transparent, colourless, water like fluid similar to plasma but low protein
produced in ciliary process
maintains IOP
provides nutrients to avascular structures eg cornea and lens
what maintains eyeballs spherical shape
hydrostatic pressure
features of vitreous humour
transparent, colourless, gelatinous fluid
lamellar arrangement of protein fibrils maintain transparency
contains phagocytes - remove unwanted cellular debris and hayalocytes
attached to caudal lens capsule, ciliary body and periphery of optic disc
maintains retina against against choroid and provides nutrients
features of the cornea
rostral fourth of eyeball
transparent
avascular
very sensitive - ophthalmic nerve
what are the 5 layers of the cornea
epithelium -squamous
bowmans membrane
stroma
descemets membrane
endothelium
features of sclera
dull white in colour
dense fibrous connective tissue and elastic fibres
vascular
attachment of extrinsic muscles
covers rest of eyeball
features of uvea
vascular
pigmented
firmly attached to the sclera at the exit of optic nerve but less well attached in other areas
what does the uvea consist of
choroid
tapetum lucidum
ciliary body
ciliary muscle
ciliary process
suspensory ligament
iris
choroid
darkly pigmented vascular lining of eye, 2/3rds of uvea, contains blood vessels supplying all internal structures of the eyeball
pigmented cells prevent light rays escaping through the eyeball
tapetum lucidum
triangular area of yellow green iridescent light - reflecting cells lying dorsal to the point at which the optic nerve leaves the eye, reflects light back to the photoreceptor cells of the retina, making use of low levels and improving night vision
ciliary body
thickened structure projecting towards centre of the eye which has two major elements - ciliary muscle and ciliary process
ciliary body
contains smooth muscle fibres that control the thickness and shape of lens
ciliary muscle
contains smooth muscle fibres that control the thickness and shape of lens
ciliary process
site of aqueous humour secretion into the posterior chamber
suspensory ligament
continuation of ciliary body
forms circular support around perimeter of lens
connect the ciliary body to the lens
iris
rostral continuation of the ciliary body
contains radial and circular smooth muscle fibres
free edge forms hole in centre = pupil
autonomic nerve supply to iris
occulomotor nerve
what does parasympathetic and sympathetic supply do to pupil
para constricts
dilate
features of retina
innermost layer of the eye
light focused on photoreceptors
information transmitted to brain via optic nerve
consists of several layers
light travels through outer layers before it stimulates the deeper photoreceptor cells
what are the layers of the retina from the layers closest to the choroid
pigmented layer
photoreceptor cells
bipolar neurons
ganglion cells
fundus
