Chapter 14, Problem 1ILQ

Watch this video (http://openstaxcollege.org/l/DanielleReed) to learn about Dr. Danielle Reed of the Monell Chemical Senses Center in Philadelphia, PA, who became interested in science at an early age because of her sensory experiences. She recognized that her sense of taste was unique compared with other people she knew. Now, she studies the genetic differences between people and their sensitivities to taste stimuli. In the video, there is a brief image of a person sticking out their tongue, which has been covered with a colored dye. This is how Dr. Reed is able to visualize and count papillae on the surface of the tongue. People fall into two large groups known as “tasters” and “non-tasters” on the basis of the density of papillae on their tongue, which also indicates the number of taste buds. Non-tasters can taste food, but they are not as sensitive to certain tastes, such as bitterness. Dr. Reed discovered that she is a non-taster, which explains why she perceived bitterness differently than other people she knew. Are you very sensitive to tastes? Can you see any similarities among the members of your family?

Summary Introduction

To analyze:

Whether I am sensitive to taste and look for similarities among my family members.

Introduction:

The people sensitive taste possess more taste buds on their tongue compared to insensitive people. The sense of bitterness is one parameter that identifies one as a taste sensitive people.

Explanation of Solution

The taste buds are spread throughout the tongue surface. However, they are more concentrated on the posterior end of the tongue. This region is specific to bitter taste. Thus people with a higher density of taste buds are more sensitive to bitter taste. They can identify this taste more efficiently and quickly than others. Moreover, the glossopharyngeal and facial nerves carry stimuli of taste from two-thirds of the anterior surface of the tongue. The vagus nerve innervates the posterior end of the tongue sensitive to bitterness. Thus this difference in stimuli transmission to the brain specifically identifies the bitter taste and makes some people sensitive to this taste.

I am not sensitive to taste as bitter substances are equally palatable for me as other tastes. Most of my family members share this trait with me.

Conclusion

Bitterness sensitivity is one parameter to identify someone as sensitive to taste. This is due to presence of more number of taste buds on the anterior end of the tongue corresponding to bitter taste stimuli.