Tongue

Tongue muscles weave in several directions, allowing the organ to curl, flatten, and press food against the teeth and palate. Intrinsic muscles change the tongue's shape, while extrinsic muscles connect it to the jaw, hyoid bone, and soft palate to move it in space. A thin membrane called the frenulum anchors the underside to the floor of the mouth.

The top surface is covered with papillae—tiny bumps that increase friction and host taste buds. Filiform papillae provide texture, whereas fungiform, circumvallate, and foliate papillae contain clusters of sensory cells that respond to dissolved chemicals in saliva. These taste receptor cells send signals to the brainstem through the facial, glossopharyngeal, and vagus nerves.

Taste buds recognize five primary tastes. Sweet signals energy-rich sugars, salty alerts to essential minerals, sour warns of acidity, bitter flags potential toxins, and umami detects amino acids like glutamate. Smell, temperature, and texture combine with taste to create flavor, which is why a stuffy nose makes meals seem bland.

The tongue also plays starring roles in speech and swallowing. Precise movements shape consonant sounds, while coordinated pushes move chewed food, or bolus, toward the pharynx. Reflexes close the soft palate and epiglottis so food enters the esophagus rather than the nasal cavity or airway. Saliva lubricates the process and contains enzymes that begin carbohydrate digestion.

Oral hygiene keeps the tongue healthy by brushing away bacteria that can cause bad breath. Drinking water, limiting sugary snacks, and avoiding tobacco protect taste buds and surrounding tissues. Doctors investigate persistent color changes, lesions, or loss of taste with exams and biopsies, and speech therapists help patients regain tongue coordination after injury or stroke.