The Tongue: Facts,
Function & Diseases
By Alina Bradford, Live
Science Contributor | October
1, 2015 11:56pm ET
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The tongue consists of eight
interwoven, striated muscles
that can move in any
direction.
Credit: Djomas | Shutterstock
Though the tongue may seem
like a simple organ, it has a
wide range of purposes,
such as licking, breathing,
tasting, swallowing and
articulating speech. Its many
talents are due to the
construction of the tongue.
Size
Typically a human tongue is
around 3.3 inches (8.5
centimeters) for men and 3.1
inches (7.9 cm) for women,
according to the University
of Edinburgh. The world’s
longest tongue is 3.97 inches
(10.1 cm) long, from the tip to
the middle of the closed top
lip, and belongs to Nick
Stoeberl of Salinas,
California, according to
Guinness Book of World
Records. The longest tongue
for a woman is 3.8 inches
(9.75 cm), belonging to
Chanel Tapper of Los
Angeles.
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Function
The tongue consists of eight
interwoven, striated muscles
that can move in any
direction, making it quite
flexible. Throughout the
muscles are glands and fat,
while the outside is covered
by a mucus membrane. The
top of the tongue, also called
the dorsum, is covered with
papillae, tiny nodes that
contain the taste buds and
the serous glands.
The serous glands secrete
some of the fluid found in
saliva, while the taste buds
taste food through receptors
that send information to the
brain. Receptors are nerve
endings that have a chemical
reaction to the food that is
being eaten. There are
different reactors for
different types of flavors,
and there are around 50 to
150 taste receptor cells
inside each taste bud,
according to Encyclopedia
Britannica.
It is a myth that different
parts of the tongue taste
different things. While it is
true that different receptors
taste different flavors, these
various receptors are
bunched in four places on
the tongue. Most of the taste
receptors are found on the
tip of the tongue, according
to the University of Texas
Medical Branch
.
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The bottom of the tongue is
smooth. Its purple color
comes from the many blood
vessels that run along the
bottom of the tongue.
The root of the tongue is the
bottom part of the tongue
that can't be seen. It has
arteries, bundles of nerves
and muscles that branch out
to the rest of the tongue.
Sticking it out
Sticking out your tongue is
considered unacceptable
behavior in many cultures,
but it is a sign of respect in
others, according to Bright
Hub Education. In Tibet,
sticking out the tongue is a
greeting. When two people
meet, they stick out their
tongues at each other.
Among the Maori people of
New Zealand, sticking out the
tongue is part of a war chant
and is meant to intimidate the
enemy. If a Maori woman
sticks out her tongue, it is a
sign of defiance. [ Infographic:
Will Your Tongue Really Stick
to a Frozen Flagpole?
]
The unusual condition
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The unusual condition known
as "geographic tongue"
causes red and white
patches that give the
appearance of continents on
a map.
Credit: Bin im Garten
Wikimedia Commons
Diseases &
conditions
Though the tongue is small,
it can develop many different
conditions. "The most
common condition that I see
as a dentist is [oral]
erythema migrans, aka
'geographic tongue,'" said Dr.
Corbin Brady of Brady Dental
Care in Des Moines, Iowa.
This condition is
characterized by red patches
on the tongue with a yellow
or white serpentine border
that disappears and
reappears on different parts
of the tongue. "Its etiology is
unknown and no known
conditions seem to cause it.
The good news is that no
pain or symptoms are
typically associated with it,"
said Brady. (Erythema
migrans is also the name of a
skin rash that is a symptom
of Lyme disease. The two are
not related.)
Like with geographic tongue,
most shape changes or
discoloration of the tongue,
such as furry tongue or
black or yellow coloring, are
harmless.
Oral thrush, or oral
candidiasis, is caused by an
accumulation of a fungus on
the lining of the mouth. It
causes creamy white lesions
on the tongue and inner
cheeks, according to the
Mayo Clinic. It is more likely
to affect babies, the elderly
and people with suppressed
immune systems, such as
people with HIV/AIDS.
Smoking can cause a wide
variety of tongue problems.
People who smoke often find
that their sense of taste is
deadened or changed.
"Nicotine is a known
vasoconstrictor, something
that limits blood flow — it
limits your bodies cells from
functioning or healing. For
the tongue, continued
smoking has shown to alter
the morphology of the
fungiform papillae, which hold
your taste buds. Smoker's
papillae have been shown to
typically be less dense in
number, have less blood flow
(less capillaries), and have
thicker 'skin' (more keratin),"
Brady said.
Smoking and other tobacco
products can also cause
tongue cancer. According to
Cancer Treatment Centers of
America
, some of the symptoms may
include:
Difficulty swallowing or
chewing
Persistent tongue and/or
jaw pain
White or red patch on the
gums, tongue, tonsil, or
lining of the mouth
A lump or thickening in the
inside of the mouth
Sore throat or feeling that
something is caught in the
throat that does not go
away
Difficulty moving the jaw or
tongue