Retina Flashcards
How many parts make up the retina? (2)
Inner neurosensory retina
Outer retinal pigment epithelium (RPE)
Surface area of retina?
1250 mm2
Diameter of Maculea lutea?
1.5 mm
What blocks UV light in the macula?
xanthophyll carotenoid pigment
What is the thickest area in the retina?
the peripapillary region (230 um)
Where is the peripheral retina thinner? (Nasal or temporal)
Temporal retina thinner than nasal retina
What is RPE made of?
A continous layer of hexagonal cuboidal cells
What forms the outer blood-retinal barrier?
The fused plasma membranes in the zonulae occludentes (in the RPE)
What is a waste product of the RPE that increasses with aging?
lipofucin
Where is te highest density of lipofuscin in RPE?
In the macula
What are the 3 neuron cells that relay light generated impulses
photoreceptors + bipolar cells + ganglion cells
what modulates the activity of the neuron light cells?
horizontal cells and amacrine cells
What is the rods to cones ratio?
20:1
What are the layers of the retina ( 10) Inner to outer?
- Retinal pigment epithelium
- Photoreceptor layer
- external limiting membrane
- outer nuclear layer
- outer plexiform layer
- inner nuclear layer
- inner plexiform layer
- ganglion cell layer
- retinal nerve fibre layer
- Internal limiting membrane
Retinal blood supply?
Inner 2/3rds –> Central retinal artery
Outer 1/3rd –> choroidal vessels
What provides an anastomosis between the retinal and choroidal circulation?
Ciolioretinal artery (branch of posterior ciliar vessels)
what makes up the inner blood retinal barrier?
retinal capillaries endothelium - non leaky tight junctions
where does the central retinal vein drain?
cavernous sinus or sometimes the superior ophthalmic vein
Which layers seperate in retinal detachemnt
the neurosensory layer (photorecptor layer) from the RPE
