Tongue: Structure and Functions

The tongue is a muscular and sensory organ located in the oral cavity. It plays a central role in various functions, including taste, speech, and the manipulation of food during digestion. Here’s a detailed note on the structure and functions of the tongue:

Structure of the Tongue

1. Muscular Tissue:

   – The tongue is primarily composed of skeletal muscle, which allows for its extensive range of movements.

   – The tongue’s intrinsic muscles control its shape, while the extrinsic muscles move it within the oral cavity.

2. Papillae:

   – Papillae are small, raised structures on the tongue’s surface.

There are three main types of papillae:

Filiform Papillae: These are small, conical structures that provide a rough surface to the tongue. They do not contain taste buds.

Fungiform Papillae: Mushroom-shaped papillae scattered across the tongue, each containing taste buds.

Circumvallate Papillae: Large, circular structures near the back of the tongue, housing numerous taste buds.

3. Taste Buds:

   – Taste buds are specialized sensory organs found in papillae.

   – They contain receptor cells that detect taste molecules (tastants) and transmit signals to the brain to interpret different tastes.

   – Taste receptors are sensitive to sweet, sour, bitter, salty, and umami (savory) tastes.

4. Salivary Glands:

   – Salivary glands within the tongue and surrounding structures secrete saliva into the mouth.

   – Saliva moistens food, aids in digestion, and contains enzymes that start breaking down food components.

Functions of the Tongue

1. Taste Sensation (Gustation):

   – The primary function of the tongue is to detect and identify different tastes, allowing humans to enjoy a variety of flavors in food and beverages.

   – Taste receptors in the tongue transmit signals to the brain, interpreting and distinguishing between sweet, sour, salty, bitter, and umami tastes.

2. Speech and Articulation:

   – The tongue is crucial in producing speech sounds (phonemes).

   – It shapes the vocal tract by moving against the palate, teeth, and other oral structures to produce different speech sounds.

3. Mastication (Chewing):

   – The tongue helps manipulate food within the oral cavity while chewing and mixing with saliva.

   – Its movements facilitate the formation of a bolus (a rounded mass of food) for swallowing.

4. Swallowing (Deglutition):

   – The tongue is essential in the swallowing process.

   – It pushes the chewed food to the back of the mouth and initiates the swallowing reflex.

5. Cleaning and Lubrication:

   – The tongue helps remove food particles from the teeth and oral surfaces.

   – Saliva secretion from salivary glands in the tongue and oral cavity keeps the mouth moist and aids in food breakdown.

Common Tongue Disorders

1. Geographic Tongue: A benign condition characterized by irregular, map-like patterns on the tongue’s surface.

2. Fissured Tongue: The presence of deep grooves or furrows on the tongue’s surface.

3. Black Hairy Tongue: This occurs when filiform papillae become elongated, discolored, and may look dark or black.

4. Oral Thrush: A fungal infection of the mouth and tongue, often caused by Candida yeast.

5. Tongue Tie (Ankyloglossia): A condition where the strip of skin beneath the tongue (lingual frenulum) restricts tongue movement.