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59 Cards in this Set

  • Front
  • Back
Refrative power of a lens is measured in
Diopters
Diopters is equal to
Reciprocal of focal distance in Meters
Emmetropia
Normal; light focuses on retina
Hypertropia
Farsighted; light focuses behind the retina
Hypertropia is corrected with
Convex lens
Myopia is
Nearsighted; light focuses in front retina
Myopia is corrected with
Biconcave lens
Astigmatism is
Irregular Curvature of the lens
Astigmatism is corrected with
Cylindric lens
Presbyobia is a result of
Loss of accomodation power of the lens occur with aging
In presbyopia, the near point moves and corrected with
further from the eye

Convex lens
Pigment layers of the retina absorb
Stray light and prevent scatter of light
Layer that converts 11-cis retinal to all trans retinal
Pigment epithelial layer
Rods and cones are not present on
The optic disk; ie blind spot
The ______ cells synapse on bipolar cells; the bipolar cells then synapse on _______
Rods and cones cells
Ganglion cells
The basis for high acuity and low sensitivity of cones is
Few cones synapse on single bipolar cells
Where is the highest visual acuity and what is the ratio?
The fovea; ratio 1:1 bipolar:cones
What is the reason for less acuity and and greater sensitivity seen in the rods?
Many rods synapse on single bipolar cell; light striking any one of the rods will synapse on the bipolar
Are the output cells of the retina
Ganglion cells
What form the optic nerve?
Ganglion cells' axons
In presbyopia, the near point moves and corrected with
further from the eye

Convex lens
Pigment layers of the retina absorb
Stray light and prevent scatter of light
Layer that converts 11-cis retinal to all trans retinal
Pigment epithelial layer
Rods and cones are not present on
The optic disk; ie blind spot
The ______ cells synapse on bipolar cells; the bipolar cells then synapse on _______
Rods and cones cells
Ganglion cells
The basis for high acuity and low sensitivity of cones is
Few cones synapse on single bipolar cells
Where is the highest visual acuity and what is the ratio?
The fovea; ratio 1:1 bipolar:cones
What is the reason for less acuity and and greater sensitivity seen in the rods?
Many rods synapse on single bipolar cell; light striking any one of the rods will synapse on the bipolar
Are the output cells of the retina
Ganglion cells
What form the optic nerve?
Ganglion cells' axons
Axons of the ganglion cells for the optic tract and end in the
Lateral geniculate body of thalamus
What fibers of the cross in the optic chiasm and what fibers remain ipsilateral?
The nasal hemiretina cross while the temporal fibers remain ipsilateral
The right optic tract is composed of _____ and synapse in the ______ tract
Left nasal hemiretina and
Right temporal hemiretina

Synpase in Right lateral genicualte
What is the geniculocalcarine tract?
Fibers from the lateral geniculate that pass posterior to the occipital lobe of the cortex
Cutting the optic nerve causes
Blindness on the same side
Cutting the optic chiasm causes
Heteronymous bitemporal hemianopia
Axons of the ganglion cells for the optic tract end in the
Lateral geniculate body of thalamus
What fibers of the cross in the optic chiasm and what fibers remain ipsilateral?
The nasal hemiretina cross while the temporal fibers remain ipsilateral
The right optic tract is composed of _____ and synapse in the ______ tract
Left nasal hemiretina and
Right temporal hemiretina

Synpase in Right lateral genicualte
What is the geniculocalcarine tract?
Fibers from the lateral geniculate that pass posterior to the occipital lobe of the cortex
Cutting the optic nerve causes
Blindness on the same side
Cutting the optic chiasm causes
Heteronymous bitemporal hemianopia
Visual Aide
Homonymous Contralateral Hemianopia; results from a lesion in optic tract
Visual
Rhodopsin belongs to what family of receptors?
G-protein coupled receptors
Rhodopsin is
the photosensitive element; opsin = protein and retinal = aldehyde of Vit.A
Light in the retinal converts ____ to ____.
11-cis retinal to all-trans retinal
Thru a series of steps ______ product is formed which activates trasnducin
Metarhodopsin II
Why is vit. A necessary for the visual pathway?
Regeneration of 11-cis retinal.
Metarhodopsin II signaling:
Metarhodopsin activates G-protein transducin which then activates phospodiesterase
Phosphodiesterase role in the visual pathway is
1.Catalyzes the conversion of cGMP to 5'GMP; decreases cGMP.
2. ↓cGMP causes closure of Na+ channels; causing hyperpolarization
3.Hyperpolarization, leads to DECREASED RELEASE OF EITHER EXCITATORY OR INHIBITORY NEUROTRANSMITTERS
Increasing light intensity causes an increase
hyperpolarization
Three cotrical cell type are involved in shape and orientation and they are:
Simple cells
Complex cells
Hypercomplex cells
The Simple cells of visual cortex are involved in
Correct position and orientation
The complex cells of the visual cortex are involved in
moving bars or edges of light with correct orientation
The hypercomplex cell of the visual cortex respond to
Lines of length and curves and angles
An opacity that forms in the lens
Cataracts
Tx for Cataracts
Removal of lens and artificially implant a lens
Intraocular pressures are extremely high which can lead to optic nerve compression
Glaucoma