Inner Nuclear Layer
The Inner Nuclear Layer is the fifth (5th) of the layers forming the retina of the human eye.
Recall that light from outside the human body enters the eye through its main structures of the cornea, aqueous humour, pupil, lens, etc. and is normally focussed onto the retina of the eye.
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 Inner Nuclear Layer consists
of three different types of cells that are packed closely together.
These three types of cells are:
- Oval-shaped Bipolar Nerve Cells
These consist of a large oval-shaped "body" containing a distinct nucleous. They are each surrounded by a quantity of protoplasm that extends into two processes, in each case one of these processes extends into the inner molecular layer (layer 4) of the retina where it tapers off to a single end-point, while the other extends into the outer molecular layer (layer 6) of the retina where it divides into multiple branches. Some texts classify the bipolar nerve cells as "rod-bipolars" and "cone-bipolars".
Bipolar Nerve Cells are most numerous of the three types of cells found in the
Inner Nuclear Layer of the retina. - The central layer (or "stratum") of the Inner Nuclear Layer contains cells called amacrine cells that are characterized by their lack of axis-cylinder process, and which extend into the inner molecular layer. Some other cells within this sub-layer are called the horizontal cells of Cajal and extend in the opposite direction into the outer molecular layer.
- There are also a few cells in the Inner Nuclear Layer that are associated with the Fibres of Müller.
For more information about related subjects see:
- Structure of the human eye
- Structure of the human retina
- What is ophthalmology?
- List of disorders of the human eye
- List of ophthalmic procedures
- Textbooks about ophthalmology