in Neural Control and Coordination (Nervous System) by

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Following is the mechanism of generation of light-induced impulse in retina:

  1. The impulses are generated in the rods and the cones of the retina through the cornea by the light rays of the visible wavelength.
  2. The photo pigments, which are the photosensitive compounds, consist of opsin, which is a protein, and retinal, which is an aldehyde of vitamin A.
  3. The light causes the dissociation of retinal from opsin, which results in structural change of opsin. Hence, due to this the membrane permeability occurs. Thus, there is generation of potential difference in the photoreceptor cells.
  4. This creates the signal, which further creates the action potential or impulse in the ganglion cell through bipolar, cells. Now these impulses or the action potentials are send to the optic nerves and then to the visual cortex the area of the brain.
  5. Here, the impulses or we can neural impulses are then analysed and thus the image is created on the retina is recognized.
  6. The image formed on the retina is based on the past memory and the past experiences.