Questions: Bipolar neurons Photoreceptors Ganglion cells

The three groups of cells in the retina that provide a direct pathway for impulses triggered at the photoreceptors to the optic nerve are:

• Bipolar neurons
• Photoreceptors
• Ganglion cells

Explanation for each option:

1. Amacrine cells: These cells are involved in the processing and integration of visual information within the retina, but they do not form a direct pathway from photoreceptors to the optic nerve. They primarily interact with bipolar and ganglion cells.

2. Bipolar neurons: These cells act as intermediaries between photoreceptors and ganglion cells. They receive signals from photoreceptors and transmit them to ganglion cells, forming a direct part of the pathway to the optic nerve.

3. Horizontal cells: These cells are involved in lateral inhibition and help integrate and regulate input from multiple photoreceptors, but they do not form a direct pathway to the optic nerve.

4. Photoreceptors: These are the cells that initially detect light and convert it into electrical signals. They are the starting point of the direct pathway to the optic nerve.

5. Ganglion cells: These cells receive input from bipolar neurons and their axons form the optic nerve, which carries visual information to the brain. They are a crucial part of the direct pathway.

In summary, the direct pathway from photoreceptors to the optic nerve involves photoreceptors, bipolar neurons, and ganglion cells.