hi let's talk about the eyeball and conjunctiva so the eyeball or the globe of the eye consists of
three layers there's a fibrous layer a vascular layer also known as the uvea and then a neural
layer or the retina in this particular session we'll see predominantly the the fibrous layer
of the eye as well as the vascular layer of the eye anteriorly and the the remainder of
the vascular layer as well as the retina will be visible upon dissection so let's uh let's
start with the fibrous layer which has two major constituents there's the sclera and the cornea and
so let me just draw a circle here and outside of that circle is the sclera also known as the whites
of the eye and within that circle would be the cornea and deep to the cornea would be elements
of the vascular layer the iris and the pupil so that sclera covers about 90% of the eye it is
contiguous with the cornea at that sclerocorneal junction that I've outlined there it serves as
an attachment site or an anchor for the various muscles of the eye the extrinsic or extra-ocular
muscles as well as the intrinsic muscles of the eye the cornea is less distributed over the the
eye so it accounts for about maybe ten percent or less it's predominantly it's it's well it's
entirely anterior it's it's clear and so we can see the the structures do it of the lluvia it's
completely avascular but it is innervated so if you've ever had a corneal abrasion you'll
you'll understand that there are efference from the the cornea and it's the the main
refractive index for the eye because it is convex anteriorly and we have aqueous humor posterior
to it that that vascular layer which we're able to say here let me erase this consists at least
anteriorly of a pigmented iris surrounding a aperture which would be the pupil and so
the iris controls the size of the pupil through two sets of muscles there are dilator pupillae
muscles which are under sympathetic innervation and sphincter pupillae muscles which are under
parasympathetic innervation so the iris is one portion of that vascular layer the other two
portions are the ciliary body and that's the part deep to the iris along the margins which anchors
the lens behind the the iris and pupil as well as produces aqueous humor and then the choroid
layer which is very highly vascularized and much more posterior and lateral to that so when we go
even more superficial than that outer fibrous layer though we have anteriorly a conjunctiva
the the conjunctiva is a mucous membrane which is going to line the interior of the eyelids as
well as the anterior of the eye itself there are two types of conjunctiva and they are completely
contiguous so there is palpebral conjunctiva and here we can see that the the eyelids have
been cut in our reflected away but on this surface which I'm writing those would all be
covered by palpebral conjunctiva and then there is bulbar conjunctiva and the bulbar conjunctiva
is going to cover the the fibrous layer of the eye anteriorly with the exception of the cornea
so around the the sclera corneal Junction we we also are going to have the limits of the
bulbar conjunctiva and it's imperfect so they don't exactly line up but we can see that that
boundary between the conjunctiva and what would just be bare sclera anteriorly there so these
conjunctiva meet one another at the Forna sees so there is a superior fornix which i'm outlining
in an inferior fornix and so if you can imagine if we were to really all of the portions of the
palpebrae together the palpebrae or the eyelids would then create a space between the palpebral
and the bulbar conjunctiva and that's what's known as the conjunctival sac and it's into
this sack that lacrimal fluid or secretions also known as tears would flow and these tears would
wash across the surface of the eye within the conjunctival sac towards the lacrimal apparatus
so towards the the lacrimal lake and associated structures immediately so we've discussed the the
layers of the globe of the eye or the eyeball in particular the sclera and cornea of the fibrous
layer as well as the the iris and pupil of the the vascular layer as well as the conjunctiva
which covers aspects of the the fibrous layer anteriorly thank you very much for your time