The tongue is no mere extension of skin -- it's a multipurpose organ in its own right. While its chief function is tasting the substances animals take into their bodies for nourishment, it participates in other important activities as well. As with other anatomical structures, it has evolved to undertake these functions to different degrees in different organisms.
A Matter of Taste
The dorsum, or upper surface, of the tongue has thousands of tiny projections called papillae. Toward the front, these are narrow and high, while toward the back they are much wider and flatter. The epithelial tissue lining the papillae contains taste buds, which resemble tiny flasks open to the mouth cavity. When food particles reach the taste buds, they come into contact with gustatory cells located within the buds; this sets off a neurochemical cascade that ends with the transmission of taste-specific information to the brain. The result is the perception of the food in the terms we describe it today -- sweet, sour, salty or bitter.
A Digestive Aid
The tongue consists mostly of powerful, smooth muscle, and is anchored to the floor of the mouth and to the hyoid bone of the throat by sturdy ligaments and other connective tissue. Because it can move freely in many directions, it can both crush food into smaller, more easily ingested portions and aid in swallowing by conveying food backward into the throat cavity. In addition, the underside of the tongue is highly absorptive thanks to a large plexus of veins there, allowing some medications to be taken sublingually rather than swallowed outright; nitroglycerin is one such example.
Let's Talk About It
Humans are the only animals that communicate using complex, sustained utterances. Were it not for the tongue, speech as we know it would be impossible. Working together with the teeth and the lips, the tongue helps humans generate up to 90 distinct words per minute and can move in an astonishing 20 separate directions. Without the tongue, the English alphabet would not include hard consonants such as "d," "t" and "k" or soft consonants such as "l" and "r."
What a Sensation!
Though perhaps not typically regarded as a sensory organ beyond taste, the tongue is more sensitive to touch than any other part of the body. Consequently, it is vital in determining, for example, whether something taken into the mouth is safe to eat -- if it is too hard or too sharp, the tongue sends this information to the brain, which decides whether to swallow the item. The tongue is also adept at sweeping through the mouth to probe for occult particles of food that may remain after swallowing.
- Photo Credit offstocker/iStock/Getty Images
What Is the Function of the Stomach?
The stomach is a hollow organ composed of several strong muscular layers. It is located under the rib cage and connected at...
What Is the Function of the Epiglottis?
The epiglottis is a structure found in the throat. Specifically, it's located behind the tongue and above the larynx. Elastic cartilage forms...
What Are the Functions of the Cranial Nerves?
There are twelve pairs of cranial nerves, all but two of which originate in the brain stem. These nerves facilitate operation of...
What Is the Function of the Digestive System?
The digestive system consists of the mouth, esophagus, stomach, pancreas, gallbladder, liver, small intestine, large intestine, colon and rectum. The main function...
Cow Tongue Facts
Your supermarket's beef showcase is mostly filled with familiar standbys, from steaks and roasts to versatile-but-bland ground beef. Food enthusiasts looking to...
Definition of Hard and Soft Palates
The palate is the roof of the mouth, according to BookRags.com, an on-demand educational resource site. The hard palate is formed by...
Mechanical & Chemical Digestion in the Mouth
The digestive system is designed to convert the foods eaten on a daily basis into materials the body can use. To do...
The Parts of Human Speech Organs & Their Definitions
Imagine that your neighbor greets you with a cheery "Good morning" but that when you open your mouth to respond, nothing comes...
How to Test Cranial Nerves
There are 12 pairs of cranial nerves that extend from the brain to parts of the head, face and trunk. They are...
What Are the Functions of the Tonsils?
Tonsils are part of the lymphatic system and protect the body from harmful germs and contaminants. They lie strategically, just behind the...