Archivio mensile:luglio 2017

Olfaction or Sense of Smell Is the Most Ancient and Primordial Sense

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From an evolutionary point of view, the sense of smell is considered the earliest and primordial of the senses as evidenced by its connection with the most remote and primitive parts of the brain, phylogenetically older. The role of primary chemical sense in primordial organisms, for interaction with the living environment (spatial orientation, food research, sexual approaches, the presence of dangers, etc.) remained essentially unchanged in present organisms. However, while for most animals it is still evident the fundamental influence of olfactory perception on the basic functions of survival and reproduction, man, due to his highest evolutionary and cultural level, often tends to consider smell a “auxiliary sense”, of secondary importance respect to other senses as sight, hearing and taste, from which we obtain information that we generally feel most important and more direct. In many animal species, thanks to its particular development, it is vital for survival: it allows for food research, warns of predators, favour mating. A blind or deaf mouse can still find food by his sneezing, but if he lacks the smell he would starve because he could not identify the food. The humanity, in the course of evolution, has increasingly deprived this prodigious sensory mode, and today it is perhaps the least used of the five. An important reference in seeking rewarding olfactory stimuli is your “olfactory memory”: During your life, you have accumulated a lot of odorous memories and surely among these, there are some that recall you moments of relaxation and happiness. The acquisition of the erected station allowed the man to use the sight to perceive the environment around himself. Smells, in fact, are often heavier than air and can, therefore, be best appreciated at ground level. In the perception of odours is involved the amygdala, that is, the portion of the brain that is related to the sexual sphere and the emotions. It is an area where sensory afferents are very fast: that is why some smells still thrill us before we are aware that they have perceived them. But emotions, by virtue of the speed at which they arise, are also alarm bells that warn us in the case, for example, of smoke, gas, toxic substances or non-edible foods. Losing the perception of odours means, therefore, losing even a formidable defence weapon. In many animal species, it is of vital importance to the functions of food research and mating. A lowering or the complete loss of sense of smell is very unpleasant because it accompanies the loss of a part of the taste. In fact, the aroma of food is perceived by the nose; The taste buds of the tongue are responsible only for the sweet and salty, bitter and acidic feelings; That’s why with the loss of smell the foods seem “flat” and insipid. Where do the smell end and taste begin? The two senses are inseparable. The temptation of coffee is not born from the flavour but from its intense aroma.

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