Neuroscience Resources for Kids

That's Tasty

Delicious, scrumptious, delectable, mouth-watering,yummy.
Stale, awful, terrible,unsavory, bland, unpalatable.

Just a few of the many words todescribe how food tastes. Notice too, that these words can also describe smells. As you mightimagine, smell and taste are often linked together. The sense of taste is also called gustation.

For food to have a taste, it must be dissolved in water. There arefour basic tastes: sweet, salty, sour and bitter:

SWEET	SOUR	SALTY	BITTER

Like a piece of cake	Like a lemon	Like, well, salt!	Like a cup of bad coffee

All other tastes come from a combination of these four basic tastes.Actually, a fifth basic taste called "Umani" has recently been discovered.Umani is a taste that occurs when foods with glutamate (like MSG) areeaten. While these tastes can be detected on many areas of the tongue,in general, the sensitivities for the basic tastes are found on differentparts of the tongue (see the picture below):

The actual organ of taste iscalled the "taste bud". Each taste bud (and there about about 10,000taste buds in humans) is made up of many (between 50-150) receptorcells. Taste buds live for only 1 to 2 weeks and then are replaced by newtaste buds. Each receptor in a taste bud responds best to one of the fourbasic tastes. A receptor can respond to the other three tastes, but itresponds strongest to a particular taste.

TheTaste Bud

Imagefrom Biodidac

There are two cranial nervesthat innervate the tongue and are used for taste: the facial nerve(cranial nerve VII) and the glossopharyngeal nerve (cranial nerve IX). The facial nerve innervates the anterior (front) two-thirds of the tongueand the glossopharyngeal nerve innervates that posterior (back) one-thirdpart of the tongue. Another cranial nerve (the vagus nerve, X) carriestaste information from the back part of the mouth. The cranial nervescarry taste information into the brain to a part of the brain stem calledthe nucleus of the solitary tract. From thenucleus of the solitary tract, taste information goes to the thalamus andthen to the cerebral cortex. Like information for smell, tasteinformation also goes to the limbic system (hypothalamus and amygdala). Another cranial nerve (the trigeminal nerve, V) also innervates thetongue, but is not used for taste. Rather, the trigeminal nerve carriesinformation related to touch, pressure and pain. Cranial Nerves
used fortaste

Did youknow?

The complete inability to taste is called ageusia and the reduced ability to taste is called hypogeusia.Ageusia is a rare disorder. It may be rare because there are 3different nerves that carry taste information to thebrain. Older people have a reduced sense of taste.This probably occurs because the taste buds are notreplaced as fast in older people.

Try some experiments to testyour sense of taste.