THIS ARTICLE ELABORATES THE FIVE MAJOR BODY SENSES AND THEIR FUNCTIONS.
The gustation, olfactory, skin and body senses
The gustation sense:
Taste or gustation is one of the five senses. It refers to the ability to detect the flavor of substances such as food, fruits drinks etc.
We humans receive taste through the sensory organs called taste buds or gustatory calculi, concentrated on the top of the tongue. The sense of taste like that of the sense of smell, involves the stimulation of chemoreceptors by dissolved materials.
Taste buds contain sensory receptors also known as chemoreceptors and are found in the papillae or top of the tongue and largely distributed in the epithelium of the tongue, soft palate, pharynx and epiglottis. This consists of small sensory nerves endings of the glossopharyngeal, facial and vagus nerves (cranial nerves 7, 9 and 10). Some of the cells have hair-like microvilli on their free borders, projecting tiny pores in the epithelium. The sensory receptors are stimulated by chemicals that enter the pores dissolved in saliva.
The sensation of taste can be categorized into 5 basic tastes: sweet, bitter, sour, and salty and umami. The recognition and awareness of umami is a relatively recent development in western cuisine. “Umami” is originally the Japanese word for “good taste”. Not surprisingly, it is the characteristics of many oriental dishes.
As taste senses both harmful and beneficial things, all basic tastes are classified as either appetitive or aversive, depending upon the effect they have on our body. Sweetness helps to identify energy rich foods while bitterness serves as a warning sign of poisons or bad foods.
Nerve impulse are generated and conducted along the glossopharyngeal, facial and vagus nerves before synapsing in the medulla and thalamus. Their final destination is the taste area of the parietal lobes of the cerebral cortex was taste is then perceived.
However, some taste consistently stimulates taste buds in specific parts of the tongue namely:
*sweet and salty= at the tip
*sour= at the sides
*bitter= at the back.
The sense of taste triggers salivation and the secretion of gastric juice. It also has protective functions.eg. When a rotten food is eaten, a reflex like squeezing of the face, gagging and vomiting may be induced.