Download Other Senses

Gustation and Olfaction:
Taste and Smell
http://www.youtube.com/watch?v=
W0w5oGVwJ_Q
1. Gustation (taste)
A. Taste cells are chemical sensitive receptors
located in taste bud clusters
•
•
Taste buds and papillae are located on the
tongue, in the throat, and on the soft palate
For a stimulus to be tasted, it must be dissolved
1. Gustation (taste)
B. Receptors are sensitive to 5 or 6 basic taste
qualities
1.
2.
3.
4.
5.
Sweetness
Saltiness
Sourness
Bitterness
Umami- MSG, glutamates
6. Curry/Eastern spices (currently up for debate)
1. Gustation (taste)
C. Other influences on taste
– Smell, touch, temperature
• Ex: flavor can be changed by food’s texture or aroma
• Examples?
1. Gustation (taste)
D. Types of tasters
• Non tasters – people unable to taste chemical
propylthiouracil (PROP), a bitter compound
• Medium tasters – people with average number of
taste buds; they taste bitter PROP at avg. level
• Supertasters – people with extremely sensitive taste
buds, high number of taste buds, highly sensitive to
PROP (women more likely than men)
Olfaction: Smell
OLFACTORY
RECEPTOR
AFFERENT
NEURONS
PREFRONTAL
CORTEX
OLFACTORY
BULB
HYPOTHALAMUS
AMYGDALA
HIPPOCAMPUS
2. Olfaction (smell)
A. Receptors for smell located on olfactory
epithelium
•
Thin membrane found in upper nasal cavity
***THE ONLY SENSORY INFORMATION NOT
ROUTED THRU THE THALAMUS BEFORE IT
PROJECTS TO THE CORTEX***
2. Olfaction (smell)
1. Olfactory cells carry info to olfactory bulb
•
Olfactory bulb activates the prefrontal cortex
2. Olfactory receptor neurons have a life cycle of
about 30 days and are continually created
3. Olfactory cells in the olfactory epithelium are
stimulated by gases dissolved in the fluid covering
the membrane
4. For a stimulus to be smelled it must be dissolved
2. Olfaction (smell)
B. Odors or scents stimulate the olfactory
epithelium
1. Odors can evoke highly emotional
memories
•
On avg., women detect odors more readily than
men (brain responses are stronger)
2. Olfaction (smell)
C. Pheromones: same species odors, used as a
form of chemical communication
D. Anosmia: loss or lack of smell. Specific
anosmia is the inability to smell a single
chemical
The case of asparagus and methanethiol…
Sensory Interaction
– Stroop effect http://faculty.washington.edu/chudler/java/ready.
html