Histology of the Visual System - Busch Flashcards
Parts of the outer tunic
Sclera - opaque, absorbs light
Cornea - transparent
Limbus - connects the two
Fxn - protect inner eye, maintains shape and consistency
Parts of the middle tunic (uvea)
Iris - outlines the pupil Ciliary body - m to dilate and constrict iris Ciliary process Choroid - vascular, pigmented Suspensory ligaments - accommodation
Parts of the inner tunic
Outer pigmented layer Retina Macula lutea Fovea - only cones Papilla - optic disc
Layers of the cornea
Corneal epithelium Bowman's layer Stroma Descemet's membrane Corneal endothelium
What type of cells anchor the corneal epithelium to Bowman’s layer?
Hemidesmosomes
What layer of the cornea transport materials from aq humor to Descemet’s membrane?
Corneal endothelium
–also lots of mito here
What type of cells found in Stroma layer of cornea? Which NS?
Myelinated nerves, collagen lamellae, fibroblasts
PNS!! Schwann cells
Where do nerves become unmyelinated in cornea?
Bowman’s layer
What in the cornea is responsible for neutralizing O2?
Corneal endothelium
glutathione pathway neutralizes excess O2
Who is gonna kick this test’s ass?!?!
WE ARE!!!!
Seriously. We got this.
What is the most common type of tissue allotransplantation?
Corneal transplant
Success > 90%
What layer in the eyeball is vascular and what tunic is it associated with?
Choroid
Middle tunic
Also pigmented
When you are squinting at Kyle’s lecture trying to read crappy screen shots of the book, what is your eye doing?
It is accommodating - to see better
Ciliary m contracted
Suspensory fibers relaxed
Lens is round
What happens to your eye in bright light?
Pupil constricts - ciliary m of iris contract
Parasymp
What happens to your eye in dim light?
Pupil dilates - radial m of iris contracts - pulls it open
Symp
What does the inner nuclear layer of the retina contain?
Amacrine and horizontal neurites
Bipolar cells - these go up to ganglion cell layer and synapse here and then sent to optic n
What does the outer nuclear layer of the retina contain?
receptors of cones and rods
What is the only retina layer that is not involved in sensory?
Pigmented epithelium
What are Muller cells and where are they in the retina?
Span most of the retina layers
Phagocytes, Na/K
Fovea centralis
Tightly packed cones arranged at an angle to the pigmented layer
Optic disc
Axons of ganglion cells turn into optic n here
Lacks photoreceptors - blind spot
What is retinal detachment? Causes?
Two layers of retina detach
Cause - trauma, vascular dz, metabolic d/o, aging
Tell me about cones
Contain photopigment - iodopsin
This contains opsin called photopsin
Sensitive to color
Tell me about rods
Contain photopigment - rhodopsin
This contains opsin called scotopsin
Sensitive to light
Pathway followed by aq humor
Produced by epithelium in ciliary processes
Fluid twerks over canal of Schlemm
Aqueous v Canal of Schlemm to episcleral v
Glaucoma - causes
Obstruction of C of S
Inflammation preventing aq from reaching trabecular meshwork
Open angle glaucoma
Common Peripheral and then central loss Painless Primary cause unclear 2 - uveitis, corticosteroids
Closed angle glaucoma
Lens enlarged
chronic - asymptomatic with optic n damage
Acute - ER! Painful, halos, atropine SE
2 major proteins in eyes?
Filensin and crystallins
What happens when proteins are not soluble in eye?
Cataracts
Esp in DM, sorbitol backs up
Chalazion
Blocked secretions
Deep or superficial
NON TENDER
Hordeolum
(sty)
Localized
TENDER
Hang in there!!!
Almost done, you are doing great!!
