What is a photoreceptor?
Photoreceptors are nerve cells that have been designed to be sensitive to light. These cells are placed in the eye, allowing to see the body and the process that work is complex and quite fascinating. There are three types of photoreceptors: bars, cones and photo -sensitive ganglium cells and each plays a clear role in vision.
When a photoreceptor is exposed to light, photosensitive proteins in the neuron are stimulated, which triggers a number of answers that convert light into a signal that can be read. This process occurs in a fraction of a second, allowing the photoreceptor to provide the brain constant information about the visual environment. Some photoreceptors are sensitized to specific spectra and the brain uses information from these cells to distinguish colors. Rather than literally seeing the color, in other words, the photoreceptor responds to the specific spectra and the brain on the reaction to determine what the eye is vision.
Photoreceptor cells that have been sensitized to specific spectra are knownLike cones, cells that make it perfect for people to "see" color. These cells have a shape similar to a cone looking at enlargement, explain the name and require bright light to work efficiently. On the other hand, the rods work in very weak light, but do not distinguish the color well. Many organisms have a mixture of rods and cones that are designed to achieve balance between the ability to see in the dark and can distinguish colors.
It seems that the third type of photoreceptor, photo -sensitive ganglium cells, plays a role in circadian rhythms and can also control the size of the pupil by providing the brain information about how much light is available. Together with rods and cones there are photo -sensitive ganglium cells in the retina. These cells were discovered in the 1960s, long after the presence of rods and cones was established. Scientists studied these cells by examining entities with blocked inputs from rods and cones.
to make foToreceptors worked properly, need a stable supply of proteins they use to detect light. One of these proteins is well synthesized from vitamin A, and therefore people are encouraged to include a lot of this vitamin in their diet. Nutritional shortcomings can lead to rejected production of these proteins, causing visual problems. Examples of proteins found in photoreceptors include: melanopsin, opsin and retina.