The Eyeball Flashcards
what are the 3 layers of the eyeball?
fibrous
vascular
inner
what does the fibrous layer of the eyeball consist of?
sclera
cornea
what is the main function of the fibrous layer of the eyeball?
provides shape and support to deeper eye structures
what does the sclera provide attachment for?
extraocular muscles
where is the cornea positioned?
centrally at front of eye
what does the cornea do?
refracts light that enters the eye
what does the vascular layer of the eye consist of?
choroid
ciliary body
iris
what is the choroid?
layer of connective tissue and blood vessels within vascular layer of eye
what is the purpose of the choroid
gives nourishment to the outer layers of retina
what is the ciliary body comprised of?
ciliary muscle and ciliary processes
what is the role of the ciliary body?
controls the shape of the lens and contributes to the formation of the aqueous humour
what is the iris?
circular structure between the lens and cornea that has an aperture in the centre (pupil)
+
the diameter of the pupil is altered by what?
smooth muscle fibres in the iris - innervated by autonomic nervous sytem
what is the inner eye formed by?
the retina
what is the role of the retina?
it is the light detecting component of the eye
what are the 2 layers of the retina?
- pigmented outer layer - single cell layer
- neural inner layer - photoreceptors
what are photoreceptors?
light detecting cells of the retina
where are photoreceptors located in the eye?
posteriorly and laterally
what is the non-visual part of the retina?
anterior part, where only the pigmented layer exists
what is the optic part of the retina?
posterior and lateral part, where both pigmented and neural layers are present
what part of the retina is viewed during opthalmoscopy?
optic
macula
centre of the retina
the macula contains a depression - what is it called?
fovea centralis - high concentration of light detecting cells
what are is responsible for high acuity vision?
the fovea centralis
optic disc?
the area that the optic nerve enters the retina
does the optic disc contain any light detecting cells?
no
what fills the posterior segment of the eyeball?
vitreous body
what is the vitre
the transparent gel that filld the posterior segment of the eyeball (posterior to the lens)
ious
what fetal remnant is found within the vitreous body?
hyaloid canal
body
where does the hylaine disc run?
from the optic disc to the lens
what are the 3 main functions of the vitreous body?
- magnifying power
where is the lens located?
between vitreous humor and pupil
what alters the shape of the lens?
ciliary body
what are the two fluid filled chambers of the eye?
anterior and posterior chambers
where is the anterior chamber located?
between cornea and iris
where is the posterior chamber located?
between the iris and the ciliary processes
the two chambers of the eye are filled with what?
aqueous humor
what is aqueous humor?
clear, plasma-like fluid that nourishes the eye
how is aqueous humor drained?
via trabecular meshwork at the base of the cornea
what happens if the drainage of the aqueous humor is obstructed?
glaucoma
what is the arterial blood supply to the eyeball?
opthalmic artery
what is the most important branch of the opthalmic artery? what does it supply?
central artery of the retina - supplies internal surface of the retina
occlusion of the central artery of the retina will result in what?
blindness
what is the venous drainage of the eyeball?
superior and inferior opthalmic veins
-» cavernous sinus
Label the eye
Label the Chambers of the eye
Label
Label the vascular layers
