Gustatory System

Taste receptors or papillae can be seen on the tongue as little red dots, or raised bumps, particularly at the front of the tongue. They do not have an axon. Information is relayed onto terminals of sensory fibers by transmitter. These fibers derive from the ganglion cells of the cranial nerves VII and IX. The facial nerve (VII c.n.) carries taste sensations from the anterior two thirds of the tongue. Fibers come from the lingual nerve (branch of the trigeminal nerve), reach the chorda tympani and, through it, the facial nerve. The posterior third of the tongue is innervated by the glossopharyngeal nerve (IX c.n.). Cellular bodies are in the plexiform ganglion. Nervous fibers from both nerves terminate at the gustative nucleus (or Nageotte's, or solitary tract nucleus), located in the dorsolateral part of the medulla oblongata.

From there, information is projected to the somatosensory cortex for conscious perception of taste and to the hypothalamus, amygdala and insula, giving the so-called "affective" component of taste, for behavioral response, (e.g. aversion, gastric secretion, feeding behavior).

The functional meaning of the gustative cortex is not yet fully understood. More than a simple terminal station for consciousness of taste, it seems to represent part of a more complex circuit which governs the alimentary behavior.

The main cortical area of taste is the opercular cortex (able to de-codify four groups of stimuli: sweet, salt, sour, and bitter). From there, projections start to the orbitofrontal and prepiriform cortex.

Pars op ecu la ri s

Cortical taste area near insula

Taste fibers in the trigeminothalamic dorsal tract

Solitary nucleus, pars gustatoria

Pars op ecu la ri s

Cortical taste area near insula

Taste fibers in the trigeminothalamic dorsal tract

Solitary nucleus, pars gustatoria

Solitary nucleus

Gustative fibers in the dorsal trigeminothalamic tract

Was this article helpful?

0 0
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Post a comment