Sensing Taste: Understanding Gustation

Taste

Overview

• Taste is the sensation of flavor perceived by the tongue and palate
• Also known as gustation
• Mediated by taste buds on the tongue and elsewhere in the oral cavity

Taste Buds

• Small sensory organs located on the surface of the tongue and elsewhere in the oral cavity
• Contain 50-100 specialized taste receptor cells
• Each taste bud has a small pore that allows molecules to enter and bind to receptors

Taste Receptors

• Specific receptors on the surface of taste receptor cells that bind to molecules of different tastes
• Five basic tastes:
  • Sweet: activated by carbohydrates, sugars, and some amino acids
  • Sour: activated by acids
  • Salty: activated by salts
  • Bitter: activated by bitter compounds, such as tannins and alkaloids
  • Umami: activated by glutamates, found in meats, seafood, and vegetables

Transduction of Taste

• When a molecule binds to a taste receptor, it triggers a chemical signal that is transmitted to the brain
• The signal is transmitted through the nervous system to the brain, where it is interpreted as a specific taste

Taste Pathways

• Taste information is transmitted to the brain through the following pathways:
  • Anterior (front) two-thirds of the tongue: chorda tympani nerve
  • Posterior (back) one-third of the tongue: glossopharyngeal nerve
  • Palate and epiglottis: vagus nerve
• The brain integrates information from these pathways to create the sensation of taste

Factors Influencing Taste

• Olfaction (smell): greatly enhances the sense of taste
• Temperature: affects the sensitivity of taste receptors
• Hormonal changes: can affect taste perception, e.g. during pregnancy
• Age: taste perception can decline with age
• Nutrition: deficiencies in certain nutrients, e.g. zinc, can affect taste perception

Taste

Overview

• The sensation of flavor perceived by the tongue and palate is known as taste or gustation.
• Taste is mediated by taste buds on the tongue and elsewhere in the oral cavity.

Taste Buds

• Small sensory organs located on the tongue and elsewhere in the oral cavity.
• Each taste bud contains 50-100 specialized taste receptor cells.
• Taste buds have a small pore that allows molecules to enter and bind to receptors.

Taste Receptors

• Specific receptors on the surface of taste receptor cells bind to molecules of different tastes.
• The five basic tastes are:
  • Sweet: activated by carbohydrates, sugars, and some amino acids.
  • Sour: activated by acids.
  • Salty: activated by salts.
  • Bitter: activated by bitter compounds, such as tannins and alkaloids.
  • Umami: activated by glutamates, found in meats, seafood, and vegetables.

Transduction of Taste

• When a molecule binds to a taste receptor, it triggers a chemical signal that is transmitted to the brain.
• The signal is transmitted through the nervous system to the brain, where it is interpreted as a specific taste.

Taste Pathways

• Taste information is transmitted to the brain through the following pathways:
  • Chorda tympani nerve: anterior (front) two-thirds of the tongue.
  • Glossopharyngeal nerve: posterior (back) one-third of the tongue.
  • Vagus nerve: palate and epiglottis.

Factors Influencing Taste

• Olfaction (smell) greatly enhances the sense of taste.
• Temperature affects the sensitivity of taste receptors.
• Hormonal changes, such as those during pregnancy, can affect taste perception.
• Taste perception can decline with age.
• Deficiencies in certain nutrients, such as zinc, can affect taste perception.