gustatives

Gustatives, or gustation, refers to the sense of taste, a component of the chemosensory system. The gustatory system detects chemical stimuli in the oral cavity and contributes to flavor perception together with smell, texture, and temperature. Taste information is detected by taste receptor cells within taste buds, which are clustered in the tongue's papillae and also found in the soft palate, pharynx, and epiglottis.

Anatomy and signaling: Tastants dissolve in saliva and bind to receptors on taste cells. Activation generates signals carried by three cranial nerves: VII (facial) for the anterior two-thirds of the tongue, IX (glossopharyngeal) for the posterior one-third, and X (vagus) for areas including the epiglottis. Signals reach the brainstem and relay to the gustatory cortex, mainly in the insula and frontal operculum, with integration in the orbitofrontal cortex. Olfactory input and somatosensory cues shape perceived flavor.

Basic tastes and receptors: Traditionally five basic tastes are recognized: sweet, sour, salty, bitter, and umami. Some researchers propose additional tastes, such as oleogustus for fat. Receptor mechanisms include T1R receptors for sweet (T1R2/3) and umami (T1R1/3), T2R receptors for bitter, epithelial sodium channels for salty, and proton-sensitive channels for sour.

Clinical and variability: Taste perception varies by age, health, and genetics. Conditions such as ageusia (loss) or hypogeusia (reduced) can arise from infections, medications, radiation, or nerve damage. Taste influences nutrition and food choice, but flavor arises from the combination of taste, smell, and other sensory inputs.