TASTE

Like smell, taste has a survival Value. Poisonous substances tend to taste bad and usually bitter while those that are nourishing taste pleasurable sweet or savoury. Together taste and smell allow animals to elevate and recognize what they eat and drink.

The Evolution of Taste

The sense of taste enables animals including humans to make the most of the variety of foods available to them. Many plants that look tempting are toxic, so genes that enable us to detect and therefore avoid these toxins have an obvious survival Value. One such gene that has been identified affords taste and sensitivity to phenyllthiocarbonide, (PIC) an organic compound that resembles many toxic compounds found in plants.

The Tongue;

The tongue is the main sensory organ for taste detection, It is the body’s most flexible muscular organ as revealed by it’s work in both nutrition and communication. It has three interior muscles and three pairs of muscles connecting it to the mouth and throat. Its surface is dotted with tiny pimplelike structures called papillae. Other parts of the mouth such as the palate pharynx, and epiglottis can also detect taste stimuli. All tastes are detected equally across the tongue accordingly to recent research. It has long been believed that different parts of the tongue are dedicated to detecting specific tastes. The tongue is well supplied with nerves that carry taste relative to the brain. Papillae contain taste buds that are distributed across the tongue. Four types of papillae that have been distinguished, villate, filiform, foliate, and fungiform. Filiform and fungiform are the smallest papillae. Each type bears a different amount of taste. Villate are the largest and form a V across the back of the tongue.

Taste Buds

A taste bud is composed of a group of about 25 receptor cells, alongside supporting cells, layered together much like a bunch of bananas. The tips of the cells form a small pore, through which taste molecules enter and contact receptor molecules. These are borne on taste hairs of tiny projection projections called microvill  that extend into the pore.

Taste and Smell Brain Areas

Taste and smell are both chemicals of sense receptors in the nose and mouth bound to incoming molecules, generating electrical signals to send to the brain.

Both sets of signals follow along the cranial nerves. Smell related Olfactory cells travel from the nose to the Olfactory Bulb, then along the Olfactory nerve into the “Olfactory Cortex” in the “Temporal Lobe” for processing. The pathway of taste related to gustatory data travels from the mouth along the branches to the tridgmmal and glossypharyngeal nerve to the medulla continues to the thalamus then to primary gustatory areas of the cerebral cortex, the taste areas of the “Somatosensory Cortex” and areas surrounding sites of activity in the “Executive Function.”

When food makes you ill (spoiled foods for example) the association can linger for a very long time making even the thought of the food repulsive. The phenomenon known as Flavor – Aversion Learning has been demonstrated by researchers at Harvard Medical School who fed rats a sweet liquid with a substance that made them briefly ill.

Thereafter avoided the liquid despite the tempting sweetness. When a food is paired with nausea flavor aversions Learning has a “Survivor’s Value” in teaching animals attracted looking foods that may be toxic, learning occurrences after only one episode but lasts  for many years.

Taste Aversions, as an alternative to killing coyotes that prey on domestic sheep; Some farmers in the Western U. S. placed lamb bait laced with an illness inducing drug around their ranches. The coyotes learned quickly to hate lamb meat and therefore stopped approaching sheep.

WRITTEN BY CAROLYN D HOGARTH FROM THE BOOK, “THE HUMAN BRAIN” BY RITA CARTER

THE BEAUTIFUL HUMAN BRAIN, AND ALL IT’S PATHWAYS…