1. Senses and Sensibility
I. Sensory modalities
II. Physiology of sensation
III. Thermal homeostasis
IV. Physiology of taste
Physiology of smell

3. Sensory Modalities Chemoreceptors
(e.g., taste, smell, O2 level in blood)

4. Sensory Modalities Chemoreceptors Mechanoreceptors
(e.g., taste, smell, O2 level in blood)
Mechanoreceptors
(e.g., touch, hearing, equilibrium, proprioreception)

5. Sensory Modalities Chemoreceptors Mechanoreceptors Photoreceptors
(e.g., taste, smell, O2 level in blood)
Mechanoreceptors
(e.g., touch, hearing, equilibrium, proprioreception)
Photoreceptors
(vision, photoperiod)

6. Sensory Modalities Chemoreceptors Mechanoreceptors Photoreceptors
(e.g., taste, smell, O2 level in blood)
Mechanoreceptors
(e.g., touch, hearing, equilibrium, proprioreception)
Photoreceptors
(vision, photoperiod)
Thermoreceptors

7. Communication by Sensory Neurons
Axon
Hillock
Sensory stimuli cause graded potentials

8. Communication by Sensory Neurons
Axon
Hillock
Sensory stimuli cause graded potentials
AP triggered in sensory neuron if graded potentials reach threshold

9. Communication by Sensory Neurons
Axon
Hillock
Sensory stimuli cause graded potentials
AP triggered in sensory neuron if graded potentials reach threshold
Sensory neurons synapse onto neurons of CNS

10. Properties of Sensory Neurons
Selectivity
Hearing
Taste
Vision

11. Properties of Sensory Neurons
Selectivity
Transduction
convert stimulus into graded potential
Na+ channels open or close
AP created in sensory neuron

12. Senses and Sensibility
I. Sensory modalities
II. Physiology of sensation
III. Thermal homeostasis
IV. Physiology of taste
Physiology of smell

13. Range of Sensory Perception
Sensory Adaptation
Thalamus filters out some stimuli

14. Range of Sensory Perception
Range Fractionation
- neurons differ in range of sensitivity

15. Senses and Sensibility
I. Sensory modalities
II. Physiology of sensation
III. Thermal homeostasis
IV. Physiology of taste
Physiology of smell

16. Thermoreceptors Peripheral Thermoreceptors Central Thermoreceptors
- epithelial tissue
Central Thermoreceptors
- hypothalamus

17. Thermal Homeostasis Stimulus: Cold Air Stimulus: High Core Temp
Peripheral
Thermoreceptor
Central
Hypothalamus
Motor Neuron
Muscle (Shivering)
Sympathetic NS
Sweat Glands

18. Senses and Sensibility
I. Sensory modalities
II. Physiology of sensation
III. Thermal homeostasis
IV. Physiology of taste
Physiology of smell

19. Chemoreceptors Chemoreceptors respond to chemicals in an
aqueous solution
The Chemical Senses:
Taste
5 receptor types
cells are highly generalized

20. Taste Buds are Located in Papillae

21. Taste Buds are Located in Papillae
Gene Simmons has LOTS
of papillae!

22. Taste Buds are Located in Papillae
Taste buds line the papillae of your tongue.

23. Taste Buds are Located in Papillae
Taste buds line the papillae of your tongue.
I Rock & Roll all Night and Party Every Day!

24. Anatomy of Taste Buds
Taste cell
Support cell
Basal cell

25. Anatomy of Taste Buds
Taste cell
Support cell
Basal cell
1) Taste cells form receptor surface and synapse with cranial nerves

26. Anatomy of Taste Buds
Taste cell
Support cell
Basal cell
1) Taste cells form receptor surface and synapse with cranial nerves
2) Supporting cells provide support for taste buds

27. Anatomy of Taste Buds
Taste cell
Support cell
Basal cell
1) Taste cells form receptor surface and synapse with cranial nerves
2) Supporting cells provide support for taste buds
3) Basal cells produce new _________

28. Hypothetical Distribution of Taste Cells

29. Hypothetical Distribution of Taste Cells

30. Distribution of Taste
Taste cell
Support cell
Basal cell
Most taste cells respond to only 1 of the 5 tastes

31. Transduction in Taste Cells
Salty & Sour flavors
- Na+ or H+ ions enter cells through existing channels

32. Transduction in Taste Cells
Sweet , Bitter & Umami more complicated
Bind to receptors and activate secondary messengers, which open Na+ channels

33. Senses and Sensibility
I. Sensory modalities
II. Physiology of sensation
III. Thermal homeostasis
IV. Physiology of taste
Physiology of smell

35. Jerry made the ice cream but Ben would test all the new flavors because Ben has hardly any sense of smell
JERRY GREENFIELD:
He kept making me put in these bigger and bigger pieces of chunks.
BEN COHEN:
Jerry always wanted to make them smaller so that there would be better chunk distribution in each scoop, or in each pint, and I insisted that it was critical that the chunks be really, really huge. And he said, “but Ben, somebody might take a spoonful and they won't get a chunk at all.” And I said, “that's OK, that's a sacrifice you have to make. It's worth it, for the big chunk they'll get in the next spoon.”

36. Olfaction (Smell)
Smell enhances the sense of Taste

37. Olfaction (Smell)
Smell enhances the sense of Taste

38. Olfaction (Smell)
Smell enhances the sense of Taste

39. Olfaction (Smell)
Smell enhances the sense of Taste
Olfactory cells

40. Olfaction (Smell) Smell enhances the sense of Taste Olfactory cells
Mucus

41. Anatomy of Olfaction Olfactory nerve olfactory bulb
Ethmoid
olfactory epithelium
basal cell
olfactory cell
support cell

42. Chemoreceptors Chemoreceptors respond to chemicals in an
aqueous solution
The Chemical Senses:
Taste
5 receptor types
cells are highly generalized
Smell
Thousands of receptor types
cells are highly specialized

43. Olfactory Cells Are Specialists
The nose can distinguish ~10,000 odors

44. Olfactory Cells Are Specialists
The nose can distinguish ~10,000 odors
10,000 Odors!
How does your nose knows?

45. Olfactory Cells Are Specialists
Nose can distinguish ~10,000 odors!
Each olfactory cell expresses a different receptor protein (only one type per cell)

46. Olfactory Cells Are Specialists
Nose can distinguish ~10,000 odors!
Each olfactory cell expresses a different receptor protein (only one type per cell)
Cells with a given receptor are randomly distributed in the olfactory epithelium

47. Olfactory Cells Are Specialists
Nose can distinguish ~10,000 odors!
Each olfactory cell expresses a different receptor protein (only one type per cell)
Cells with a given receptor are randomly distributed in the olfactory epithelium
All neurons of a given type converge in the olfactory bulbs of the brain

48. point of convergence (in olfactory bulb)
Convergence of Olfactory Cells
nasal epithelium
Ethmoid Bone

49. Physiology of Olfaction
Volatile odor enters nasal cavity

50. Physiology of Olfaction
Volatile odor enters nasal cavity

51. Physiology of Olfaction
Volatile odor enters nasal cavity
Odor dissolves in mucus lining

52. Physiology of Olfaction
Volatile odor enters nasal cavity
Odor dissolves in mucus lining
Bind to receptor protein

53. Physiology of Olfaction
Volatile odor enters nasal cavity
Odor dissolves in mucus lining
Bind to receptor protein
Na+ channels open

54. Physiology of Olfaction
Volatile odor enters nasal cavity
Odor dissolves in mucus lining
Bind to receptor protein
Na+ channels open
AP sent to Olfactory Bulb

55. Physiology of Olfaction
Volatile odor enters nasal cavity
Odor dissolves in mucus lining
Bind to receptor protein
Na+ channels open
AP sent to Olfactory Bulb
To the Brain

57. Hmmm…
That smells like bacon

58. The Dirty Secret Behind Flavor
So why do McDonald’s fries taste soooooo good?

59. New Jersey Smells Great!
McDonalds French Fries: Potatoes, partially hydrogenated soybean oil, natural flavor (beef, wheat and dairy sources), dextrose, sodium acid pyrophosphate (to preserve natural color). Cooked in partially hydrogenated vegetable oils (may contain partially hydrogenated soybean oil and/or partially hydrogenated corn oil and/or partially hydrogenated canola oil and/or cottonseed oil and/or sunflower oil and/or corn oil). Contains derivatives of wheat and dairy.