550
UNIT 3
Regulation and Integration of the Body
15
Choroid
Axons
of
ganglion
cells
Pigmented
layer of retina
Pigmented
layer of retina
Axons of
ganglion cells
Outer segments
of rods and cones
Nuclei of
ganglion
cells
Nuclei of
rods and
cones
Nuclei
of bipolar
cells
(a) Posterior aspect of the eyeball
(c) Photomicrograph of retina
Neural layer of retina
Pigmented
layer of
retina
Central artery
and vein of retina
Optic
nerve
Sclera
Choroid
Optic disc
Pathway of light
Pathway of light
Pathway of signal output
(b) Cells of the neural layer of the retina
Amacrine cell
Horizontal cell
Rod
Photoreceptors
• C
one
Bipolar
cells
Ganglion
cells
Figure 15.6
Microscopic anatomy of the retina.
(a)
The axons of the ganglion cells form
the optic nerve, which leaves the back of the eyeball at the optic disc.
(b)
Light (indicated by
the yellow arrow) passes through the retina to excite the photoreceptor cells (rods and cones).
Information (output signals; gray arrow) flows in the opposite direction via bipolar and ganglion
cells.
(c)
Photomicrograph (145
3
).
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