Gustation

• 5 tastes can be distinguished

  • sour
  • sweet
  • bitter
  • salty
  • umami
• Odors from food can pass upward from mouth into the nasal cavity, stimulating olfactory receptors
• Olfaction is more sensitive than taste (10 000 odors VS 5 tastes)
• If you have a cold or allergies and your nose is blocked and you cannot taste your food, olfaction is blocked not gustation
• Gustatory receptor cells are responsible for the sense of taste. They are located in the taste buds. Each one has a long gustatory hair (chemoreceptors)
• Taste buds are found on the tongue (10 000), on the roof of the mouth and in the throat. They are found in elevations on the tongue called papillae
• Adaptation to taste occurs within 1-5 minutes of constant stimulation
• Tastants are chemicals that stimulate gustatory receptor cells
• Tastants need to be dissolved in saliva before they can enter taste buds and stimulate gustatory receptors
• Mechanism of action for gustation

  1. tastant reaches gustatory hair
  2. neurotransmitter is released and signal is sent to the sensory neurons
  3. signals first reaches the limbic system and hypothalamus (reaction and memory)
  4. signal continues to the parietal lobe of cerebral cortex
• Sweet foods make reactions of pleasure whereas bad foods make reactions of disgust (taste aversion). These are survival mechanisms