Problem 1 - Anatomy and Physiology of Animals

Question

Watch this video (http://openstaxcollege.org/// 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?

Step-by-Step Solution

Answer

Personal taste sensitivity can vary and may share similarities with family members due to genetic factors.

Step 1: Understand Papillae and Taste Sensitivity

We first note that papillae are small structures on the surface of the tongue that contain taste buds. A greater density of papillae generally indicates a higher sensitivity to certain tastes.

Step 2: Categorize the Groups

There are two main groups based on papillae density: 'tasters' who have a high density of papillae and are more sensitive to certain tastes, and 'non-tasters' who have a lower density of papillae and less sensitivity, particularly to bitterness.

Step 3: Analyze Personal Taste Sensitivity

Reflect on your own taste experiences to assess your sensitivity to flavors like bitterness. Consider performing a test by tasting a commonly bitter food, like black coffee, to see if you perceive it as more or less bitter compared to others.

Step 4: Observe Familial Patterns

Evaluate the taste sensitivity in your family members to see if there is a pattern or similarity in taste sensitivity, which might suggest a genetic component to taste perception similar to Dr. Reed's studies.

Key Concepts

papillae density

Papillae are tiny, visible bumps on the tongue's surface, each home to taste buds. They play a vital role in taste sensitivity. Imagine your tongue as a landscape where papillae are hills. The denser these hills, the more sensitive you might be to the flavors you encounter.

The density of papillae varies among individuals, which influences how we experience taste. For someone with a high papillae density, their tongue is essentially packed with many more taste buds, making them more sensitive to certain flavors, especially those that are bitter or sour.

Papillae density can be easily visualized by applying a colored dye to the tongue. This allows the bumps to stand out, providing a clearer picture of their density and a better understanding of an individual's taste sensitivity. If you have a high papillae density, you are more likely to have a richer and more intense taste perception.

tasters and non-tasters

People are often divided into two categories based on their taste sensitivities, determined by papillae density: "tasters" and "non-tasters." Tasters have more papillae on their tongues, thus, more taste buds. This increased number of taste buds makes them more sensitive to specific flavors, particularly those which are bitter. This group might find Brussels sprouts or dark chocolate quite intense.

On the flip side, non-tasters have fewer papillae and taste buds, resulting in a lower sensitivity to flavors, especially bitterness. For non-tasters, bitter foods may taste less intense, or even pleasant. It's fascinating to see how such physical differences in papillae can lead to such different tasting experiences.

This classification into tasters and non-tasters is an effective way to understand one's taste profile—giving a personal insight into why certain flavors are more or less appealing.

taste buds

Taste buds are the microscopic sensory organs contained within the papillae, and they are crucial for detecting different flavors in the foods we eat. Each taste bud is a collection of cells that work together to relay flavor information—sweet, sour, salty, bitter, and umami—to the brain.

The average human has thousands of taste buds scattered on the tongue, roof of the mouth, and throat. However, the number can significantly vary based on papillae density. This variation directly impacts how intensely we perceive different tastes.

When you eat something, the chemicals from the food dissolve in your saliva and make contact with the taste buds, activating them. Each activated taste bud sends a signal to the brain, which then interprets the flavor. More taste buds mean a stronger signal and a more pronounced taste perception.

genetic component of taste perception

The ability to perceive tastes is influenced heavily by genetics. This is why members of the same family might share similar taste sensitivities.

Genes determine the density of papillae on your tongue and, consequently, the number of taste buds you have. This genetic component can explain why some people are tasters and others are non-tasters. It also highlights why certain flavors might be universally loved or hated within households.

Understanding this genetic aspect clarifies why individual taste experiences vary so widely. For instance, Dr. Danielle Reed discovered her non-taster status through genetic research, explaining her unique taste experiences compared to those around her. This illustrates how personalized our sense of taste is, being a genetic narrative of each individual's sensory perception.