eye anatomy Flashcards
what is normal intraocular pressure
10-21mmHg
where do tendons in the eye attach
sclera
what kind of epithelium is conjunctiva
stratified columnar (only one in body)
what is in conjunctiva
goblet cells
where is conjunctiva
on sclera and inside of eyelid
where is visual acuity highest
fovea
what surrounds the fovea
macula
where is optic disc relatively
medial
what is in the fovea
cones
what are the 3 types of cones
red/green/blue
what is the photosensitive protein in rods
rhodopsin
why are photoreceptors actually “dark receptors”?
constant expulsion of glutamate which is turned off when light hits the rod
how does light affect a rod
GPCR changes confirmation and downregulates cGMP which closes Na+ channel, causing cell to hyperpolarise leading to stymying of glutamate neurotransmitter emission
what are the 3 important cells in the light seeing pathway
rods/cones->bipolar cells-> ganglion cells,
what is in the choroid
lots of BVs - blood supply to rods and cones
where do bipolar and ganglion cells get blood supply
central retinal artery (think where they are)
what cells of rods, bipolar, ganglion cells does light hit first
ganglion (it’s really back to front)
why does the eye need so much blood
photoreceptors highly metabolically active
what phagocytoses worn out eye membrane
pigment epithelial cells (weirdly)
where is lacrimal gland
lateral superior to eye (under eyebrow basically)
where do tears drain
nasolacrimal duct
what innervates lacrimal gland
facial nerve
where does the cornea get nutrition from
aqueous humour
what is humour behind the lens called
vitreous
what is glaucoma
retinal damage from raised intraocular pressure
what are the 2 types of glaucoma
open angle which is chronic - trabecular fibres block canal of Schlemm so aqueous humour can’t drain
primary angle closure - acute - emergency
total block of canal of Schlemm, extreme pain and loss of vision
what is first line trtment for open angle glaucoma
laser trebeculoplasty
what is second line trtment for open angle glaucoma
beta adrenergic antagonists topical eyedrops timolol
with or without prostaglandin analogues - latanoprost
reduces production of aqueous humour
where is aqueous humour produced
cilliary body
what is normal angle between cornea and iris
40 degrees
what vitamins essential for eye health
C and A
