Layers of the Retina Flashcards
Retinal cells are highly organized into 10 layers (outer to inner)
- RPE (supports photoreceptors)
- Photoreceptor
- External limiting membrane
- Outer nuclear layer
- Outer plexiform layer
- Inner nuclear layer
- Inner plexiform layer
- Ganglion cell layer
- Nerve fiber layer
- Internal limiting membrane
*layers 2-10 are considered neural/sensory retina.
How are RPE cells attached to the choiriocapillaris
Through Bruch’s
RPE is outer to ___ and inner to ___
Outer to photoreceptors and inner to choriocapilaris
Subretinal space
Gap between the RPE and the photoreceptors.
How does the RPE and photoreceptors stay close together regardless of the sub retinal space?
They are held in case approximation due to
- Microvilli that extend from the apical surface of RPE cells that envelop the outer segment tips of photoreceptors.
- Interphotoreceptor matrix (IPM) secreted by the RPE cells has adhesive properties.
- IOP due to aqueous humor.
- Presence of vitreous humor (+/-) may or may not keep photoreceptors against RPE
-No gap junctions, tight junctions, or desmosomes here
A common site of neurosensory retinal detachment (Photoreceptors separated from RPE)
Subretinal space- there are no gap or tight junctions, or desmosomes here
Outer vs inner
Outer- choroid/sclera
Inner- vitreous
Photoreceptor layer
-Composed of?
Composed of outer and inner segments of the photoreceptor cells. (outer is touching the RPE and inner is closer to the cilium)
Contains projections of the muller cells that extend between inner segments, and then extend to the outer/external limiting membrane.
Outer limiting membrane (OLM) or external limiting membrane (ELM)
- Located where?
- Composed of what?
Junction between:
photoreceptors: photoreceptors
Photoreceptors: muller cells
Composed of zonula adherens
Outer nuclear layer (ONL)
Composed of photoreceptor cell bodies- they are arranged in different layers due to height.
Generally, cone nuclei lie in a single layer next to the external limiting membrane(more outer, closer to choroid), and rods are arranged in several rows inner to the cone bodies (closer to the vitreous- they are taller)
When you hear “nuclear,” you should think ___
Cell body
Outer plexiform layer (OPL)
What does it contain?
Composed of synapses between
Photoreceptors and bipolar dendrites
Photoreceptor axons and horizontal cell processes
Horizontal cell processes and bipolar dendrites
When you hear “plexiform,” think ___
Synapse
What border is within the OPL?
The middle limiting membrane. It is a border between the inner 2/3 and outer 1/3 retinal blood supply.
Created by the desmosome-like attachments between bipolar dendrites and horizontal cell processes that resemble a discontinuous membrane.
The middle limiting membrane is located where and formed by what
It is located within the outer plexiform layer and is created due to desmosome like attachments between bipolar dendrites and horizontal cell processes. Creates a discontinuous membrane that borders the inner 2/3 and outer 1/3 retinal blood supply.