The Outer Nuclear Layer is
the
seventh (7th) of the layers forming
the retina of
the human eye that light reaches after entering the eye: That is,
after light from outside the body enters the eye through it's main structures
of the cornea, aqueous
humour, pupil, lens,
etc..
The retina is composed of several layers which, together, form
the "screen" in the eye onto which an image of the area
viewed by the eye is formed, and information about that image is
segmented into packets of information that are passed to the
visual cortex of the brain via the optic
nerve.
The Outer Nuclear Layer is
similar to the Inner
Nuclear Layer in that both contain several sub-layers
of oval-shaped components.
In the case of the outer nuclear layer there are
two types of cells. These are called rod-granules and cone-granules,
as they are connected with the rods and cones, respectively.
The rod-granules are the most numerous the the
two types.
These are located at various different levels within the
outer nuclear layer of the retina.
Fine processes extend from two opposite sides of each rod-granule.
The "outer-process" (which extends towards the back of the retina)
is aligned with a single rod in
Jacob's
Membrane (layer 9) of the
retina. The "inner-process" traverses towards the
Outer
Molecular Layer (layer 6) of the retina where it terminates at a point of connection
with the "outer-process" of a rod-bipolar.
The cone-granules are located close the Membrana
Limitans Externa, through which each one is located
in alignment with a single cone in Jacob's
Membrane (layer 9).
Each cone-granule contains a pear-shaped ("pyriform") nucleus that
almost completely fills the cell and is
connected, via a thick process that terminates in multiple thin fibrils,
with
the outer process of a cone-bipolar in the Outer
Molecular Layer (layer
6).
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