Outer nuclear layer

Outer nuclear layer
Section of retina. (Outer nuclear layer labeled at right, fourth from the bottom.)
Plan of retinal neurons. (Outer nuclear layer labeled at left, third from the bottom.)
Details
Identifiers
Latinstratum nucleare externum retinae
TA98A15.2.04.012
FMA58684
Anatomical terminology
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The outer nuclear layer (or layer of outer granules or external nuclear layer), is one of the layers of the vertebrate retina, the light-detecting portion of the eye. Like the inner nuclear layer, the outer nuclear layer contains several strata of oval nuclear bodies; they are of two kinds, viz.: rod and cone granules, so named on account of their being respectively connected with the rods and cones of the next layer.

Rod granules

The spherical rod granules are much more numerous, and are placed at different levels throughout the layer.

Their nuclei present a peculiar cross-striped appearance, and prolonged from either extremity of each cell is a fine process; the outer process is continuous with a single rod of the layer of rods and cones; the inner ends in the outer plexiform layer in an enlarged extremity, and is imbedded in the tuft into which the outer processes of the rod bipolar cells break up.

In its course it presents numerous varicosities.

Cone granules

The stem-like cone granules, fewer in number than the rod granules, are placed close to the membrana limitans externa, through which they are continuous with the cones of the layer of rods and cones.

They do not present any cross-striation, but contain a pyriform nucleus, which almost completely fills the cell.

From the inner extremity of the granule a thick process passes into the outer plexiform layer, and there expands into a pyramidal enlargement or foot plate, from which are given off numerous fine fibrils, that come in contact with the outer processes of the cone bipolars.

References

Public domain This article incorporates text in the public domain from page 1016 of 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
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1:posterior segment 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:Schlemm's canal 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscule 15:inferior rectus muscule 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea 27:sclera 28:choroid 29:superior rectus muscle 30:retina1: posterior segment2: ora serrata3: ciliary muscle4: ciliary zonules5: Schlemm's canal6: pupil7: anterior chamber8: cornea9: iris10: lens cortex11: lens nucleus12: ciliary process13: conjunctiva14: inferior oblique muscule15: inferior rectus muscule16: medial rectus muscle17: retinal arteries and veins18: optic disc19: dura mater20: central retinal artery21: central retinal vein22: optic nerve23: vorticose vein24: bulbar sheath25: macula26: fovea27: sclera28: choroid29: superior rectus muscle30: retina
1:posterior segment 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:Schlemm's canal 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscule 15:inferior rectus muscule 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea 27:sclera 28:choroid 29:superior rectus muscle 30:retina
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