DIGESTIVE ORGANS 
405 
and are arranged on the back of the tongue in the form of 
a V (Figure 364). 
Our power to taste sweet, sour, bitter, and salt, which 
are the four fundamental tastes in man, is due mainly 
to certain nerve cells located 
on the larger papillae. The 
food stimuli received by the 
special sensory cells of the 
papillae are carried to the brain 
Figure 364 . — Tongue of Man 
Showing Two of the Three 
Kinds of Papilla. 
The circumvallate papillae 
are at base of tongue and about 
five or six in number; the 
fungiform papillae are numer¬ 
ous, round, mushroom-like pro¬ 
jections scattered over the 
surface of the tongue. The 
third type of papillae, the fili¬ 
form, are the most numerous 
and like coarse hairs. You can 
recognize these papillae on your 
own tongue. 
Figure 365 . — Diagram of Taste 
Cells in the Tongue. 
The taste cells are much longer 
than the surrounding cells. The 
nerve which carries taste stimuli 
to the brain ends among these 
long cells. 
by the taste nerves. In the brain the food stimulus is 
interpreted as sweet, sour, or bitter (Figure 365). 
LABORATORY STUDY 
Blindfold in turn several members of the class and have each hold his 
nose while a small amount of some highly flavored food is placed on the 
tongue. Such common foods as maple sirup, vanilla extract, mar¬ 
malade, jams, etc., are admirable for this test. Make a record of each 
