Chapter 15 Summary

Reset | Show All Answers

1.   Flavor is produced by the combination of taste and retronasal olfaction (olfactory sensations produced when odorants in the mouth are forced up behind the palate into the nose). Flavor sensations are localized to the ----- mouth nose throat , even though the retronasal olfactory sensations come from the olfactory receptors high in the nasal cavity.
Check answers for this question

2.   Taste are globular clusters of cells (like the segments in an orange). The tips of some of the cells (microvilli) contain sites that interact with taste molecules. Those sites fall into two groups: ion channels that mediate responses to ----- salts sugars and acids, and G protein–coupled receptors that bind to ----- salty sweet and bitter compounds as well as compounds described as having “umami” taste.
Check answers for this question

3.   The tongue has a bumpy appearance because of structures called papillae. Filiform papillae (the most numerous) have no taste buds. Taste buds are found in the ----- circumvallate foliate fungiform papillae (front of the tongue), ----- circumvallate foliate fungiform papillae (rear edges of the tongue), and ----- circumvallate foliate fungiform papillae (rear center of the tongue), as well as on the ----- bottom roof of the mouth.
Check answers for this question

4.   Taste projects ----- contralaterally ipsilaterally from the tongue to the medulla, thalamus, and cortex. It projects first to the insula in the cortex, and from there to the orbitofrontal cortex, an area where taste can be integrated with other sensory input (e.g., retronasal olfaction).
Check answers for this question

5.   Taste and olfaction play very ----- different similar roles in the perception of foods and beverages. Taste is the true nutritional sense; taste receptors are tuned to molecules that function as important nutrients. Bitter taste is a detection system. Sweet taste enables us to respond to the sugars that are biologically useful to us: sucrose, glucose, and fructose. Salty taste enables us to identify sodium, a mineral crucial to survival because of its role in nerve conduction and muscle function. Sour taste permits us to avoid acids in concentrations that might injure tissue.
Check answers for this question

6.   Umami, the taste produced by , has been suggested as a fifth basic taste that detects protein. However, umami lacks one of the most important properties of a basic taste: hardwired affect. Some individuals like umami, but others do not. Taste receptors are not only in the mouth but also in the gut. Digestion breaks down proteins into their constituent amino acids, and the glutamate released stimulates gut glutamate receptors, leading to conditioned preferences for the sensory properties of the foods containing protein.
Check answers for this question

7.   The importance of taste to survival requires that we be able to recognize each taste quality independently, even when it is present in a mixture. By coding taste quality with labeled lines in much the same way that frequencies are coded in ----- hearing vision , nature has ensured that we have this important capability. These labeled lines are noisy. For example, acids are able to stimulate fibers mediating saltiness, as well as those mediating sourness. Thus, acids tend to taste both salty and sour.
Check answers for this question

8.   Foods do not taste the same to everyone. The Human Genome Project revealed that we carry about 25 genes for bitter taste. The most studied bitter receptor responds to PROP and shows allelic variation in humans, leading to the designations “PROP nontaster” for those who taste the least ----- bitterness sweetness and “PROP taster” for those who taste the most. In addition, humans vary in the number of fungiform papillae (and thus taste buds) they possess. Those with the most taste buds are called supertasters and live in a “neon” taste world; those with the fewest taste buds live in a “pastel” taste world. Psychologists discovered these differences by testing people’s ability to match sensory intensities of stimuli from different modalities. For example, the bitterness of black coffee matches the pain of a ----- mild severe headache to nontasters but resembles a ----- mild severe headache to supertasters. The way foods taste affects palatability, which in turn affects diet. Poor diet contributes to diseases like cancer and cardiovascular disease.
Check answers for this question

9.   For taste, unlike olfaction, liking and disliking are ----- hardwired learned ; for example, babies are born liking sweet and salty and disliking bitter. When we become deficient in salt or sucrose, liking for salty and sweet tastes, respectively, increases. Junk foods are constructed to appeal to these preferences. Liking the burn of chili peppers, on the other hand, is ----- acquired inherited and, with the exception of some pets, is essentially limited to humans. Taste buds are surrounded by pain fibers; thus supertasters perceive greater burn from chilis than do nontasters. In addition, fungiform papillae, structures that house taste buds, are innervated by touch fibers; thus supertasters perceive greater touch sensations from fats (e.g., creamy, viscous, thick) in foods.
Check answers for this question