Bipolar cells

Bipolar cells are specialized neuronal cells that play a crucial role in the visual system. They are part of the retina, the light-sensitive tissue lining the inner surface of the eye, and serve as intermediaries between photoreceptor cells (rods and cones) and ganglion cells.

Function

Bipolar cells receive signals from photoreceptor cells, which detect light entering the eye, and transmit these signals to ganglion cells, which send the information to the brain via the optic nerve. There are two types of bipolar cells: ON-bipolar cells and OFF-bipolar cells. ON-bipolar cells are activated by an increase in light intensity, while OFF-bipolar cells are activated by a decrease in light intensity. This dual system allows the visual system to detect changes in light intensity more accurately.

Structure

Bipolar cells are named for their structure, which features two distinct ends or poles. One end of the bipolar cell forms synapses with the photoreceptor cells, while the other end forms synapses with the ganglion cells. The part of the bipolar cell that connects these two ends is called the axon, and it carries signals from the photoreceptor cells to the ganglion cells.

Role in Disease

Dysfunction or damage to bipolar cells can lead to various visual disorders. For example, retinitis pigmentosa, a group of genetic disorders that cause progressive vision loss, is often associated with the death of bipolar cells. Similarly, macular degeneration, a leading cause of vision loss in older adults, can also involve damage to bipolar cells.

See Also

• Photoreceptor cell
• Ganglion cell
• Retina
• Visual system
• Retinitis pigmentosa
• Macular degeneration

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