SENSE OF TASTE
The receptors for taste are found in taste buds, most of which are in papillae on the tongue (Fig. 9–2). These chemoreceptors detect chemicals in solution in the mouth. The chemicals are foods and the solvent is saliva (if the mouth is very dry, taste is very indistinct). There are five (perhaps more) general types of taste receptors: sweet, sour, salty, bitter, and savory.
Savory (also called umami or glutamate) is a taste like grilled meat. We experience many more dif-ferent tastes, however, because foods are often com-plex chemicals that stimulate different combinations of receptors, and the sense of smell also contributes to our perception of food.
Figure 9–2. Structures concerned with the senses of smell and taste, shown in a mid-sagittal section of the head.
QUESTION: If we sniff something pungent, why can we often taste it as well? (Follow the inhaled air.)
Some taste preferences have been found to be genetic. People with more than the average number of taste buds find broccoli very bitter, whereas people with fewer taste buds may like the taste.
The impulses from taste buds are transmitted by the facial and glossopharyngeal (7th and 9th cranial) nerves to the taste areas in the parietal-temporal cor-tex. The sense of taste is important because it makes eating enjoyable. Some medications may interfere with the sense of taste, and this sense becomes less acute as we get older. These may be contributing fac-tors to poor nutrition in certain patients and in the elderly.