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12 Cards in this Set
- Front
- Back
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Visible light |
Photo receptors only detect visible light. The wavelengths that are reflected off an object to our photo receptors and absorbs all the other colors. |
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Pathway of light |
Light goes through the cornea and into the pupil projected into the lens which changes its shape. The lens are able to bend the light onto the photoreceptors. |
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Retina |
Made up of 3 cell layers. Ganglion cells, bipolar cells, and photoreceptors. The ganglion cells are connected to the optic nerve. It looks contains the optic disk aka Blind spot because there are no receptors. |
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Photoreceptors |
Outersegment that contain disc with photo pigment protiens which absorb light. Inner segment has the cellular organelles. Synaptic end contain the synaptic vehicles with neurotransmitters. |
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Rods |
Light sensitive that can activate small senses of light. Normally used at night and can't detect color. Photo pigment is called rhodosin. They also allow for peripheral vision. |
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Cones |
Less sensitive to light that provide color vision and more active during the day. We have 3 types of cones, blue, green, and red cones. Contain photopsin pigments. |
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Rods in the dark |
Rods are demoralized by Na channels being always open by cGMP (key that unlocks gate) Cell becomes more depolarized and undergo action potential to release inhibitory neurotransmitters onto bipolar cells. |
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Rods in the light |
Na channels are closed using the GMP and hyperpolarizing it. Photopigment recieves light allowing the Retinal to convert from 11-cis form to all-trans form where retinal is separated from opsin. Opsin then activates g protien and alpha subunits dissociated. Alpha subunit activates cGMP phosphodiesterase. It converts to GMP |
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Rods in light pt. 2 |
Bipolar cells can no depolarize and stimulate ganglion cells releasing glutamate neurotransmitters. |
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Neural pathway for vision |
Axons running through optic nerve from Ganglion cells also from the superior colliculi synapse at the Thalamus but not before crossing over to opposite sides in the optic chiasm. Then, interferon connects from thalamus to occipital lobes and interprets what photo receptors saw. |
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Fovea centralis |
Area of greatest visual acuity where wavelengths of light fall directly onto cones that occur better in good light. |
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Greatest light sensitivity |
Adjacent to fovea Centralia where rods are activated in dim light. Many rods converge into one single ganglion cells that enhances light sensitivity. |
