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Taste and Smell
Chemo senses
detect airborne
                              chemicals

                              detect chemicals
                              dissolved in saliva
Chemosenses provide survival value for animals
Chemo senses
Chemo senses
Chemo senses
Some molecules
  can have same
  structures, but
  different ¡°smells¡±
Others can have
  different
  structures and be
  id¡¯d as same smell
350 types of
olfactory receptors,
each sensitive to a
particular group of
odors.

Each olfactory
receptor neuron
contains only 1
type of olfactory
receptor.
Chemo senses
Fatty, soapy


  Fatty, cheese,dairy



  Orange, rose, waxy


  Fatty, cheesy, waxy




Almond
The functional grpasocc. w/ a compound (COOH for acids;
OH for alcohols) determines the general area of the
olfactory bulb that is activated, and the compounds length
determines the position of the area.
Rats can distinguish betwn the 2 forms of Carvone, but
not Limoene.
Others are more complex due to
    downstream processing.
Chemo senses
Chemo senses
Now add other odors, w/ their 100¡¯s of
molecules. We will not experience a
jumble¡­here we¡¯ll smell coffee, bacon eggs!!!
Onion smell labeled pizza perceived
 more positively than one labeled body
 odor
Activity pattern in olfactory receptors the same. The label changed
perception & this was reflected in different activity of secondary ctx.
Chemo senses
Chemo senses
¨C All over, no taste
            buds

          ¨C Tip & sides

                                 fungiform
          ¨C Folds along back &
            sides




folaite
? Site of transduction

? Each receptor cell
  responds to a ltd # of
  molecule types.

? Receptors synapse w/ 3
  cranial nerves
   ¨C These also carry non-
     taste info such as pain
     &tmp
Chemo senses
? Rat studies indicate
  some taste perception
  is based on
  distributed coding.

? Chemicals that
  produced similar firing
  patterns were
  perceived as the same
  (red & green lines)
Chemo senses
? Involves taste & olfaction

? Orbitofrontalctx combines
  taste, olfaction, primary
  somatosensory &what
  pathway

? Has neurons that respond
  to both taste & smell;
  others taste & vision

? Often respond to similar
  qualities (smell of sweet &
  taste of sweet)
Chemo senses
Chemo senses
? A.L. Fox (worked for
  DuPont) prepped some
  PTC., co-worker c/o
  bitter taste from
  dust¡­.Fox tasted
  nothing.

? A.F Blaheslee ( a
  geneticist) dispensed
  PTC to 2500 Ss at a
  conference.
  ¨C 28%: ¡°tasteless¡±
  ¨C 66% ¡°bitter¡±
Why?
  ¨C Different # of receptors
  ¨C Some have specialized
    neurons

More Related Content

Chemo senses

  • 3. detect airborne chemicals detect chemicals dissolved in saliva Chemosenses provide survival value for animals
  • 7. Some molecules can have same structures, but different ¡°smells¡± Others can have different structures and be id¡¯d as same smell
  • 8. 350 types of olfactory receptors, each sensitive to a particular group of odors. Each olfactory receptor neuron contains only 1 type of olfactory receptor.
  • 10. Fatty, soapy Fatty, cheese,dairy Orange, rose, waxy Fatty, cheesy, waxy Almond
  • 11. The functional grpasocc. w/ a compound (COOH for acids; OH for alcohols) determines the general area of the olfactory bulb that is activated, and the compounds length determines the position of the area.
  • 12. Rats can distinguish betwn the 2 forms of Carvone, but not Limoene.
  • 13. Others are more complex due to downstream processing.
  • 16. Now add other odors, w/ their 100¡¯s of molecules. We will not experience a jumble¡­here we¡¯ll smell coffee, bacon eggs!!!
  • 17. Onion smell labeled pizza perceived more positively than one labeled body odor
  • 18. Activity pattern in olfactory receptors the same. The label changed perception & this was reflected in different activity of secondary ctx.
  • 21. ¨C All over, no taste buds ¨C Tip & sides fungiform ¨C Folds along back & sides folaite
  • 22. ? Site of transduction ? Each receptor cell responds to a ltd # of molecule types. ? Receptors synapse w/ 3 cranial nerves ¨C These also carry non- taste info such as pain &tmp
  • 24. ? Rat studies indicate some taste perception is based on distributed coding. ? Chemicals that produced similar firing patterns were perceived as the same (red & green lines)
  • 26. ? Involves taste & olfaction ? Orbitofrontalctx combines taste, olfaction, primary somatosensory &what pathway ? Has neurons that respond to both taste & smell; others taste & vision ? Often respond to similar qualities (smell of sweet & taste of sweet)
  • 29. ? A.L. Fox (worked for DuPont) prepped some PTC., co-worker c/o bitter taste from dust¡­.Fox tasted nothing. ? A.F Blaheslee ( a geneticist) dispensed PTC to 2500 Ss at a conference. ¨C 28%: ¡°tasteless¡± ¨C 66% ¡°bitter¡±
  • 30. Why? ¨C Different # of receptors ¨C Some have specialized neurons

Editor's Notes

  1. Animals are able to detect chemical signals because they have Important evolutionary job ¨C keep genes in gene pool
  2. Emotional reaction happen firstSmell has a direct link to the amgdyla
  3. Dogs are better at smelling, It¡¯s because they have a lot more olfactory receptors, not because theirs are better
  4. Olfactory neuron will only carry one olfactory kind of receptor
  5. Olfactory receptor neurons are located in nose, send axons to glomerulus in olfactory bulb (right under the brain)Receptors distributed all over
  6. Similar patterns of activity, then we perceive similar odorsDon¡¯t need to memorize the acids
  7. Highly organized further organized by the size of the molecules
  8. Red means lots of activityCool colors = less activityblack Arrows show that the activity is the sameWhite arrows show differences in activityRats can tell the different kind of carvone depending on the different activity of the neurons
  9. Neuron enters the olfactory bulb, goes to the piriform cortex, then gets bounced to the orbitofrontal cortex, then straight to the prefrontal areaThe olfactory senses are the only ones that don¡¯t stop at the thalamus
  10. This is why it takes a little longer for us to realize the emotional responseUsually, the olfactory was take the longer route
  11. Expectation alters perception of how favorable the smell was
  12. Subjects were told that it was either cheddar cheese or sweat, but it was actually both togetherChemical caused the exact same pattern of activity, the pattern of activity downstream was different depending on what they thought they were smelling
  13. Umami, sour, bitter, salt, sugar
  14. Know filiform, know that there are 4 forms of papillae
  15. TASTE budshave receptors that bind together and at the tips, transduce
  16. Area in the brain stem, first area information synapses
  17. Olfaction and taste are linked downstream such that perception of taste is heavily dependent on olfactory Smell influences taste
  18. There is a difference between the two group