makuaisti

Makuaisti, in Finnish, denotes the sense of taste and is the sensory system that allows organisms to detect chemical compounds in foods and beverages. It contributes to nutrition, safety, and enjoyment by helping identify nutritive substances and avoid potentially harmful toxins.

Taste receptors are organized in taste buds on the tongue and in other areas such as the soft palate, epiglottis, and pharynx. Each taste bud contains taste receptor cells that respond to chemical tastants. When a tastant binds its receptor, a signal is transmitted via the facial (VII), glossopharyngeal (IX), and vagus (X) nerves to the gustatory cortex in the insula and frontal operculum.

Traditionally, five basic tastes are recognized: sweet, sour, salty, bitter, and umami. Sweet and umami signal energy-rich nutrients; bitter can indicate toxins; sour and salty reflect chemical properties of foods. Some researchers describe additional qualifiers, but the five-taste model remains standard.

Taste sensitivity varies with age, genetics, and health. Genetic differences influence bitter perception (for example, how some people taste certain bitter compounds). Children and older adults may have different taste sensitivity, and some people are termed supertasters.

Taste interacts with smell to form flavor. Olfactory input from retronasal routes contributes substantially to flavor perception, while temperature and texture also influence taste experiences.

Disorders of makuaisti include ageusia (loss of taste), hypogeusia (reduced taste), and dysgeusia (distorted taste). Causes include infections, medications, head injury, smoking, and metabolic diseases; certain infections, notably COVID-19, can cause temporary or prolonged taste disturbances.