Question
All are true about optic nerve except:
| A. |
Arises from axons of bipolar neurons
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| B. |
approx 5cm long
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| C. |
Covered by 3 layers continuous with meninges
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| D. |
a and b
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Show Answer
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Correct Answer » A
Explanation
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A. Arises from axons of bipolar neurons
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The optic nerve arises from the axons of ganglion cells in the retina, not bipolar neurons.
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Bipolar neurons serve as interneurons connecting photoreceptors (rods and cones) with ganglion cells.
The retina is a layered structure involved in the first stages of visual processing. It contains three main types of neurons:
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Photoreceptors (rods and cones): Detect light and initiate the visual signal.
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Bipolar cells: Serve as interneurons, relaying signals from photoreceptors to ganglion cells.
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Ganglion cells: Their axons converge at the optic disc and form the optic nerve.
- The optic nerve length is approximately 4 to 5 cm, extending from the back of the eye to the optic chiasm.
