Bruce Nelsonfor, Age 13, Of New York, N.Y.,for his question:
How do we taste?
When a spoonful of ice cream enters the mouth, the brain gets the good news almost at once. There are nerves that report on the flavor and others that report on the smooth texture. Other nerves report that, the delicious morsel is cold, and some of the news is relayed from nerves in the back of the nose which send messages of smell to the brain.
The sense of taste is a very complicated job of communications, and very often it combines with the sense of smell. Most of the tasting job is done by small bodies cal1ed taste buds. Each bud is a wad of sensitive cells which is connected by a nerve fiber to the brain. We find the taste buds in groups buried in the rough bumps on the tongue. Other taste buds may be present in the palate, the insides of the cheeks and other membranes inside the mouth.
There are small oval fields of taste buds around the edge of the tongue and a large y shaped fie1d at the back of the tongue. An oval area of taste buds in the center of the tongue does not seem to do as much work as those around the edge and back of the tongue.
The papillae, the bumpy pimples which covet the surface of the tongue, 8re always moist with saliva. The taste buds are usually grouped under the mushroom or cup shaped papillae, and here the saliva collects in pockets of liquid. This is important, for the taste buds can respond only to chemicals dissolved in liquid.
When food enters the mouth, it is chewed and doused with saliva. The liquid with its dissolved chemicals seeps into the pits on the bumpy tongue and reaches the taste buds. Some taste buds respond to some flavors, some respond to others. The message of this or that flavor is flashed to the brain immediately, and you know
Whether you are eating salt or sugar, sweet flavors are relayed to the brain from the taste buds at the tip of the tongue. Salty flavors are relayed by fields of taste buds on either side of the sweet tasting buds. Soon flavors are reported by taste buds on the sides of the tongue at the back. Bitter flavors are reported by the v shaped field of taste buds on the back of the tongue.
Other nerve endings in the mouth report on the texture and temperature of the food. Still more nerve endings relay messages to the brain on the odor of each mouthful of food.
Most food has some odor which mingles with the air. The nerve endings in the nose respond to odors in gaseous form. The taste buds, it is thought, can distinguish only sweet and salt, sour and bitter. But most foods are a blend of these tastes. Texttn;e, temperature and odor sensations also add their reports to the flavor, and the combinations of these various reports make it possible for the brain to distinguish an endless number of different flavors and tastes.