Final answer:
Sensory neurons on the tongue detect chemicals in food corresponding to five basic tastes. Each taste has specific receptors, with salty and sour detected through ion transport, and sweet, bitter, and umami through G-protein coupled receptors that send signals to the brain via cranial nerves.
Step-by-step explanation:
When you taste something, sensory neurons that are specialized for detecting chemicals responsible for taste are employed. These neurons are organized into taste buds on the tongue. The specific taste neurons detect the five primary tastes: sweet, salty, sour, bitter, and umami. For example, a salty taste involves Na️ ions from NaCl entering taste neurons, causing excitation. Sour tastes are detected by sensory neurons that respond to increased H️ ion concentrations from acidic substances. Sweet, bitter, and umami flavors involve specialized G-protein coupled receptors on taste neurons, which, upon binding with their respective tastants, trigger neurotransmitter release onto other sensory neurons. These connected neurons carry the signal to the brainstem and then to the gustatory cortex of the cerebral cortex for taste perception.
Further, the sensation of taste is also connected to cranial nerves, particularly the facial, glossopharyngeal, and a small part of the vagus nerve, which directly connect to the different regions of the tongue and convey the sensory information to the brain for processing.