Flashcards in The Visual System Deck (55)
Neural component of the eye.
- designed to transduce a photon of light into something the nervous system will recognize (action potential)
- transduced through chemical reactions into action potentials
Primary (only) purpose of non-neural eye components.
refract (bending) photons of light
Non-neural components of the eye.
cornea, aqueous chamber, lens, vitreous chamber/fluid, neural retina, fovea/macular region, ciliary muscle and lens, iris
How does the cornea receive nutrients?
tears (avascular - CN VII damage can cause cornea to dry out)
Attach lens to ciliary muscles.
This helps maintain the shape of the eye.
where all photons of light are refracted to, greatest acuity
surrounds fovea centralis, yellowish in color b/c of protein lutein (filters out ultraviolet light and helps to protect the eye)
Retina is an extension of the ___________.
diencephalon (thalamus, hypothalamus, etc.)
What occurs when the ciliary muscle fibers are relaxed?
suspensory ligament/zonular ligament are taught, pulling on lens to elongate lens for focusing on distance vision
What occurs when the ciliary muscle fibers are contracted?
narrows aperture, allowing suspensory ligaments to be relaxed, thickening/rounding the lens for focusing on near vision
Iris (two series of muscles)
circular: sphincter pupilli (parasympathetic)
radially orientation: dilation of iris (sympathetic)
between 400-700 nm in wavelength
Round muscle around the border of the iris.
ciliary muscle (CN III)
Connect the photoreceptor cells to the retinal ganglion cells (output cells).
Rods (1) and Cones (3: red, blue, green)
These cells spread info laterally rather than vertically.
Horizontal Cells and Amacrine Cells
Superficial: optic fiber layer
axons of retinal ganglion cells
Ganglion cell layer
cell body of retinal ganglion cells
Inner plexiform layer
synapses are occurring between amacrine and bipolar cells with ganglion cells
Inner nuclear layer
cell heavy with cell bodies of bipolar cells, horizontal cells, and amacrine cells
Outer plexiform layer
cell free layer! synapses for horizontal, bipolar cells, and photoreceptor cells
Outer nuclear layer
contains cell bodies of rods and cones
Inner segments and Outer segments
Series of blood vessels that feed the deeper structures of the eye.
optic fiber layer-->ganglion cell layer-->inner plexiform layer-->inner nuclear layer-->outer plexiform layer-->outer nuclear layer-->inner segments and out segments-->pigment epithelium-->choroid
- marks the center of the fovea, in the center of the macula lutea
- greatest concentration of photoreceptors, bipolar, to ganglion cells (1:1:1 relationship)
- creates your greatest visual acuity
- prone to degenerative diseases
Right visual world
Left Temporal Retina
Right Nasal Retina
Left visual world
Right Temporal Retina
Left Nasal Retina