Problem 150 - Objective Biology for NEET

Question

Assertion: Tounge contains receptor for taste. Reason: The upper surface of the tounge has small projections called papillae, all of which bear taste buds which act as receptor for taste.

Step-by-Step Solution

Answer

Yes, the tongue does contain receptors for taste. The assertion and reason are in agreement with the biological understanding of the human sensory system. The small projections on the upper surface of the tongue, known as papillae, bear the taste buds which receive and interpret tastes, thereby functioning as taste receptors.

Step 1: Understanding the Structure of the Tongue

Firstly, it should be known that the tongue is a muscular organ in the mouth which serves several functions, including tasting. The upper surface of the tongue is covered with small bumps known as papillae.

Step 2: Exploring Papillae and Taste Buds

Secondly, all papillae bear taste buds, which are the actual sensory receptor sites where chemicals from the food we eat are translated into nerve impulses that the brain interprets as specific tastes.

Step 3: Confirming the Tongue as a Receptor for Taste

Lastly, given that the taste buds exist on the papillae and that they are responsible for interpreting the chemical composition of food as different tastes, it can be confirmed that the tongue contains receptors for taste. The reason given about papillae housing the taste buds, which in turn act as sensors for taste, aligns with the assertion.

Key Concepts

Tongue Structure

The tongue is a vital organ not just for tasting, but also for speaking and swallowing. It is primarily composed of muscle tissues, which give it flexibility and strength. These muscles help the tongue move in various directions, enabling us to form speech and chew food effectively.
The upper surface, which we readily see, is called the dorsum. It is coated with a mucous membrane that contains small, visible bumps known as papillae. These papillae give the tongue its rough texture.

• The base of the tongue connects it to the floor of the mouth and supports its movement.
• The muscular nature of the tongue facilitates a wide range of motions, enhancing our ability to taste, speak, and swallow.

The structure of the tongue, with its muscle layers and papillae, plays a crucial role in its many functions.

Papillae

The term 'papillae' refers to the numerous small, knob-like projections on the surface of the tongue. These anatomical features are more than just bumps; they play critical roles in tasting and touch.
There are different types of papillae, each with its own function:

• Fungiform papillae: Mushroom-shaped and located mainly at the tip and edges of the tongue, they contain taste buds.
• Filiform papillae: Thin, thread-like, and the most numerous, but they do not contain taste buds. They help the tongue sense texture.
• Circumvallate papillae: Larger, dome-shaped structures located at the back of the tongue, each housing many taste buds.
• Foliate papillae: Located on the sides of the tongue, containing taste buds and playing a role in perceiving taste.

Papillae not only aid in the perception of taste but also in the tactile sensation, providing information about the texture of food.

Taste Buds

Taste buds are the actual sensory organs responsible for detecting taste. They reside primarily in papillae structures on the tongue's surface. Each taste bud contains numerous taste receptor cells, which are sensitive to different flavors: sweet, sour, salty, bitter, and umami.
When food enters the mouth, chemicals from the food dissolve in saliva and interact with the taste receptor cells within the taste buds. This interaction triggers nerve impulses that travel to the brain, allowing us to perceive specific tastes.

• Taste buds can have a lifespan ranging from 10 to 14 days, after which they regenerate.
• They are distributed throughout the tongue but are most densely populated at its tip and sides.

Therefore, through taste buds, the tongue acts as a critical receptor, translating chemical signals from food into our flavorful experience.