the orbit and eye Flashcards
what is the white part of the eye called?
sclera
what covers the sclera?
conjunctiva
what are conjunctival vessels?
veins in the white part of the eye (sclera)
what covers the iris?
cornea
what is found between the cornea and sclera?
limbus (corneoscleral junction)
what does the conjuntiva cover?
- reflects onto the eyelid and upper eyelid (conjunctival fornix)
- covers the sclera
what is the outer layer of the eye made of?
fibrous tissue
what parts is the outer layer of the eye made up of?
2 parts
sclera- muscle attachment
cornea- 2/3 of refractive power
what is the middle layer of the eye also known as?
-uvea or vascular layer
how many parts can the uvea be broken down into and what are they?
-3 parts
iris- pupil diametes
ciliary body- controls iris, shape of lens and secretion of aqueous humour
choroid- nutrition and gas exchange (thickest part)
what is the inner layer of the eye also called?
retina (photosensitive layer)
what can the anterior segment (infront of the lens) of the eye be divided into?
- anterior chamber (between cornea and iris)
- posterior chamber (between iris and suspensory ligaments)
what does the posterior segment (behind the lens) contain?
- contains vitreous body
- vitreous humour
- vitreous body is a common location for ‘floaters’
what is a cataract?
clouding of the lens
what is the iridocorneal angle?
- the angle in ‘open-angle’ and ‘closed-angle- glaucoma
- junction or area between the iris and cornea
what is circulation of aqueous?
- liquid produced and secreted in ciliary body due to the processes
- it then passes into the posterior body, over the lens, nourishing the lens
- it then passes through the opening of the pupil into the anterior chamber, once in the anterior chamber it can circulate and nourish the internal aspect of the cornea
- the aqueous is then reabsorbed into the scleral venous sinus (canal of Schlemm) at the iridocorneal angle
what can occur if there is raised intra ocular pressure?
ischaemia and glaucoma
what supplies most of the blood to the eye?
opthalmic artery
what does the opthalmic artery derive from?
- the internal carotid artery
- passes through the cavernous sinus and branches off into the opthalmic artery
what is an end artery?
-an artery with insufficient anastamoses to maintain viability of the tissue supplies if arterial occlusion occurs
what is the only artery that supplies the retina and why is it important?
- the central artery of the retina (its an end artery)
- if it gets blocked you get ischamia of the retina
what is the only vein that drains into the retina?
the central vein
what is the danger triangle of the face?
-upper lip/external nose
what is highlighted pink?
the superior ophalmic vein
what is highlighted pink?
the optic nerve
what is highlighted pink?
-the inferior ophalmic vein (drains mainly into the superior opthalmic vein)