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22 Cards in this Set
- Front
- Back
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Light passes through _ before hitting the retina.
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cornea, anterior chamber (aqueous humor), lens, vitreous chamber (viterous humor)
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What area is specialized for highest visual acuity?
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Fovea
(pointed in the direction of sight) |
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What is Schlemm's canal?
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Trabecular meshwork in the anterior chamber that drains aqueous humor produced in the posterior chamber.
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What disease is associated with blockage of Schlemm's canal?
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Glaucoma
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The visual axis is drawn through the _, and it divides _ from _.
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Fovea
Divides temporal retina (L) from nasal retina (M) |
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What spot includes the fovea and a broader region?
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Macula
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The visual blind spot is located at the _.
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Optic disk
- no photoreceptors - nerve exit - vessel entry and exit |
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Describe the pupillary light reflex.
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consensual changes result in pupil diameter in response to changes in light intensity
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Describe accommodation.
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Focus close
Increase refractive power Fatter lens (review muscles and zonule fibers) |
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What is visual acuity?
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Ability to distinguish two points.
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Visual field:
LS/RS LI/RI Draw retinal field: |
Retinal field is flipped in BOTH vertical and horizontal planes:
RI/LI RS/LS |
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General term for retinal layer that contains synaptic connections:
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Plexiform layer
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General term for retinal layer that contains cells:
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Nuclear layer
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Important retinal layers from inside out (direction of light travel):
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Inner Limiting membrane
Nerve fiber layer *Retinal ganglion cell layer *Inner plexiform layer *Inner nuclear layer (bipolar, horizontal, amacrine) *Outer plexiform layer *Outer nuclear layer (photoreceptor cell bodies) Outer limiting membrane *Photoreceptor layer Pigmented epithelium (retinitis pigmentosa) Choroid layer Sclera |
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In which retinal layer are the photoreceptor cell bodies located?
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Outer nuclear layer
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Are photo receptors located in the outer nuclear layer?
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No, only the cell bodies are located in the outer nuclear layer.
Photoreceptors have their own layer farther out. |
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What cell types are present in the inner nuclear layer?
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Bipolar
Horizontal Amacrine I - (don't worry about it) |
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Where are action potentials generated in the retina?
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Ganglion cells
(2 cell layers away from photoreceptor) |
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Which cells in the inner nuclear layer mediate lateral effects?
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Horizontal
Amacrine |
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What makes the fovea histologically distinct?
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Lateral displacement of inner nuclear (H,B,A,I) and ganglion cells
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What are 2 reasons for increased visual acuity in the fovea?
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More direct pathway for light
Less divergence in connections (closer to 1:1) |
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Describe the two types of photoreceptors.
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Rods
- low light (scotopic) - concentrated peripherally Cones - day (photopic) and color - concentrated centrally (fovea) |
