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Spatial relationships among the cellular tapetum, visual streak and rod density in dogs.

Yamaue Y, Hosaka YZ, Uehara M - J. Vet. Med. Sci. (2014)

Bottom Line: Maximum rod density was found in the area dorsal to the visual streak, and the density in that area was significantly higher than the rod density in the visual streak and accorded spatially with the thickest part of the tapetum.The horizontal visual streak was found over the horizontal line through the optic disc in the temporal half and extended slightly into the nasal half.The visual streak was located within the tapetal area, but ventrally to the thick part of the tapetum.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Anatomy, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan.

ABSTRACT
The dog visual system is well suited to dim light conditions due to rod-dominated retina and the reflective tapetum. The topographical distributions of rods and thickness of the tapetum of the dog were quantified in retinal whole mounts stained with thionine, and spatial relationships among the tapetum, rod density and visual streak of high ganglion cell density were elucidated. The relationship between the retina and tapetum was analyzed in parasagittal sections stained with thionine or hematoxylin-eosin. The tapetum was thick in its center, and the thickest part consisted of 9 to 12 tapetal cell layers. Rod density ranged from 200,000 to 540,000/mm(2). Maximum rod density was found in the area dorsal to the visual streak, and the density in that area was significantly higher than the rod density in the visual streak and accorded spatially with the thickest part of the tapetum. The horizontal visual streak was found over the horizontal line through the optic disc in the temporal half and extended slightly into the nasal half. The central area of the highest density of ganglion cells was approximately located midway between the nasal and temporal ends of the visual streak. The visual streak was located within the tapetal area, but ventrally to the thick part of the tapetum.

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Rods (A–C) and ganglion cells (D–F) in retinal areas 4 (A, D), 2 (B, E) and 9 (C, F) of DR12 (Refer to caption of Fig. 5). D–F are taken from the same microscopic fields of A–C, respectively. In area 4 corresponding to the thickest part of the tapetum, rods are small in diameter, and ganglion cells are intermediate in density. In area 2 corresponding to the dorsal thin part of the tapetum, rods are large in diameter, and ganglion cells are low in density. In area 9 corresponding to the visual streak, rods are intermediate of areas 2 and 4 in diameter, and ganglion cells consist exclusively of a small type showing highest density. Arrows, cones. Scale bar=10 µm (A–C) and 100 µm (D–F).
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fig_003: Rods (A–C) and ganglion cells (D–F) in retinal areas 4 (A, D), 2 (B, E) and 9 (C, F) of DR12 (Refer to caption of Fig. 5). D–F are taken from the same microscopic fields of A–C, respectively. In area 4 corresponding to the thickest part of the tapetum, rods are small in diameter, and ganglion cells are intermediate in density. In area 2 corresponding to the dorsal thin part of the tapetum, rods are large in diameter, and ganglion cells are low in density. In area 9 corresponding to the visual streak, rods are intermediate of areas 2 and 4 in diameter, and ganglion cells consist exclusively of a small type showing highest density. Arrows, cones. Scale bar=10 µm (A–C) and 100 µm (D–F).

Mentions: Rod Densities: In the histological observations without statistical examination, there was a clear difference in rod densities of the selected areas (Fig. 3Fig. 3.


Spatial relationships among the cellular tapetum, visual streak and rod density in dogs.

Yamaue Y, Hosaka YZ, Uehara M - J. Vet. Med. Sci. (2014)

Rods (A–C) and ganglion cells (D–F) in retinal areas 4 (A, D), 2 (B, E) and 9 (C, F) of DR12 (Refer to caption of Fig. 5). D–F are taken from the same microscopic fields of A–C, respectively. In area 4 corresponding to the thickest part of the tapetum, rods are small in diameter, and ganglion cells are intermediate in density. In area 2 corresponding to the dorsal thin part of the tapetum, rods are large in diameter, and ganglion cells are low in density. In area 9 corresponding to the visual streak, rods are intermediate of areas 2 and 4 in diameter, and ganglion cells consist exclusively of a small type showing highest density. Arrows, cones. Scale bar=10 µm (A–C) and 100 µm (D–F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4363019&req=5

fig_003: Rods (A–C) and ganglion cells (D–F) in retinal areas 4 (A, D), 2 (B, E) and 9 (C, F) of DR12 (Refer to caption of Fig. 5). D–F are taken from the same microscopic fields of A–C, respectively. In area 4 corresponding to the thickest part of the tapetum, rods are small in diameter, and ganglion cells are intermediate in density. In area 2 corresponding to the dorsal thin part of the tapetum, rods are large in diameter, and ganglion cells are low in density. In area 9 corresponding to the visual streak, rods are intermediate of areas 2 and 4 in diameter, and ganglion cells consist exclusively of a small type showing highest density. Arrows, cones. Scale bar=10 µm (A–C) and 100 µm (D–F).
Mentions: Rod Densities: In the histological observations without statistical examination, there was a clear difference in rod densities of the selected areas (Fig. 3Fig. 3.

Bottom Line: Maximum rod density was found in the area dorsal to the visual streak, and the density in that area was significantly higher than the rod density in the visual streak and accorded spatially with the thickest part of the tapetum.The horizontal visual streak was found over the horizontal line through the optic disc in the temporal half and extended slightly into the nasal half.The visual streak was located within the tapetal area, but ventrally to the thick part of the tapetum.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Anatomy, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan.

ABSTRACT
The dog visual system is well suited to dim light conditions due to rod-dominated retina and the reflective tapetum. The topographical distributions of rods and thickness of the tapetum of the dog were quantified in retinal whole mounts stained with thionine, and spatial relationships among the tapetum, rod density and visual streak of high ganglion cell density were elucidated. The relationship between the retina and tapetum was analyzed in parasagittal sections stained with thionine or hematoxylin-eosin. The tapetum was thick in its center, and the thickest part consisted of 9 to 12 tapetal cell layers. Rod density ranged from 200,000 to 540,000/mm(2). Maximum rod density was found in the area dorsal to the visual streak, and the density in that area was significantly higher than the rod density in the visual streak and accorded spatially with the thickest part of the tapetum. The horizontal visual streak was found over the horizontal line through the optic disc in the temporal half and extended slightly into the nasal half. The central area of the highest density of ganglion cells was approximately located midway between the nasal and temporal ends of the visual streak. The visual streak was located within the tapetal area, but ventrally to the thick part of the tapetum.

Show MeSH
Related in: MedlinePlus