Inner nuclear layer

Inner nuclear layer
Section of retina. (Inner nuclear layer labeled at right, fifth from the top.)
Plan of retinal neurons. (Inner nuclear layer labeled at left, seventh from the top.)
Details
Identifiers
Latin	stratum nucleare internum retinae
TA	A15.2.04.014
FMA	58686
Anatomical terminology [edit on Wikidata]

The inner nuclear layer or layer of inner granules is made up of a number of closely packed cells, of which there are three varieties, viz.: bipolar cells, horizontal cells, and amacrine cells.

Bipolar cells

The bipolar cells, by far the most numerous, are round or oval in shape, and each is prolonged into an inner and an outer process.

They are divisible into rod bipolars and cone bipolars.

• The inner processes of the rod bipolars run through the inner plexiform layer and arborize around the bodies of the cells of the ganglionic layer; their outer processes end in the outer plexiform layer in tufts of fibrils around the button-like ends of the inner processes of the rod granules.
• The inner processes of the cone bipolars ramify in the inner plexiform layer in contact with the dendrites of the ganglionic cells.

Connection types

Midget bipolars are linked to one cone while diffuse bipolars take groups of receptors. Diffuse bipolars can take signals from up to 50 rods or can be a flat cone form and take signals from seven cones. The bipolar cells corresponds to the intermediary cells between the touch and heat receptors on the skin and the medulla or spinal cord.^[1]

Horizontal cells

The horizontal cells lie in the outer part of the inner nuclear layer and possess somewhat flattened cell bodies.

Their dendrites divide into numerous branches in the outer plexiform layer, while their axons run horizontally for some distance and finally ramify in the same layer.

Amacrine cells

The amacrine cells are placed in the inner part of the inner nuclear layer, and are so named because they have not yet been shown to possess axis-cylinder processes.

Their dendrites undergo extensive ramification in the inner plexiform layer.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

• Histology image: 08008loa – Histology Learning System at Boston University
• Histology image: 07902loa – Histology Learning System at Boston University

Anatomy of the globe of the eye
Fibrous tunic (outer)	Sclera Episcleral layer Schlemm's canal Trabecular meshwork Cornea Limbus layers Epithelium Bowman's Stroma Dua's layer Descemet's Endothelium
Uvea/vascular tunic (middle)	Choroid Capillary lamina of choroid Bruch's membrane Sattler's layer Ciliary body Ciliary processes Ciliary muscle Pars plicata Pars plana Iris Stroma Pupil Iris dilator muscle Iris sphincter muscle
Retina (inner)	Layers Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium Cells Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia Other Macula Foveola Fovea centralis Parafovea Perifovea Optic disc Optic cup Ora serrata
Anatomical regions of the eye	Anterior segment Adnexa Fibrous tunic Anterior chamber Aqueous humor Iris Posterior chamber Ciliary body Lens Capsule of lens Zonule of Zinn Posterior segment Vitreous chamber Vitreous humor Retina Choroid
Other	Keratocytes Ocular immune system Tapetum lucidum Eye care professional Eye disease Refractive error Accommodation Physiological Optics Visual perception