How does the smell work?

Frequent feeling, known as olfaction, uses a sensory organ called nose to transmit information about the smell of olfactory cortex in the brain. Diffuse suspension of the relevant molecules called odors are analyzed by the nose using the molecular lock scheme and keys, in which the odors are identified by their unique chemical signatures.

The meaning has evolved as a means of detecting information about survival about the outside world, especially for food assessment. The fragrance is the oldest of the senses, with analogues reaching up to the first animals 600 million years ago. One of the five primary senses, the smell is most intimately associated with the creation of memories. Human olfactory epithelium is about 16 cm², contrast with some dogs that have 150 cm².

With the procedure of Color Vision, SIGHT can be considered a primary human sense: the smell plays a more limited role, primarily related to food and sexual gluing. The olfactory receptor neurons are surrounded by supporting cells that eliminate mucus, which facilitates the pickup of odor molecules.The nostrils are covered with hair to prevent unwanted organisms and inanimate material from the environment.

olfactory receptor neurons, each of which can detect several molecules, project axons into the brain through olfactory nerve. These projections converge on a small (~ 50 micron) structure called olfactory bulb, eventually converging only about 100 neurons. Given the degree of convergence found in the olfactory part of the nervous system, it may be surprising that we can distinguish between so many odors, but apparently any activation patterns between 100 neurons are the work. Most people can distinguish between a few thousand odors and varying degrees of intensity and a combination of fragrances.