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26 Cards in this Set
- Front
- Back
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What is the term for a sense that can sense something at a distance?
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distal
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What are three characteristics for chemicals that we can smell?
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1.volatile (vaporize easily)
2. Must be soluble in both water and lipids. 3. Usually organic |
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How many different odors can be discriminated?
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about 10000
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What is the basic outline of the olfactory sense?
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1. Chemicals inhaled
2. Dissolved in olfactory epithelium (or mucosa) 3. Interact with receptors 4. Nerves go directly to olfactory bulb and brain. |
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What is the roughly bottom-to-top layout of mucusa and olfactory bulb?
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mucous, cilia of receptors, nerve fibers, cribriform plate (porous bone), olfactory bulb
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What are two things you can say about the receptor cells?
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1. Lock and key binding based on compound shape.
2. Not specific: respond in different amounts to different chemicals. |
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What about organization of mucosa into zones?
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1. Divided into 4 zones.
2. Different types of receptors in each zone, but a given receptor is only found in one zone. 3. Makes sense: heavier compounds fall sooner, also related to airflow. |
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How does the mucosal organization relate to the olfactory bulb organization?
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1. Zones in mucosa correspond to zones of glomeruli.
2. Each different type of receptor ends up in only one or two glomeruli (bundle of synapses). 3. Many to one reduction. |
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What are the two types of olfactory cortices and where are they relatively located?
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Primary olfactory cortex (piriform), back, secondary olfactory cortex (orbito-frontal) front
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Is the olfactory pathway ipsi- or contralateral? What is another part of the brain that it connects to?
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Ipsilateral (two olfactory bulbs on each side). Amygdala, related to emotions.
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How is intensity coded?
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More receptors receiving chemical, more intense smell (summation).
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How is perceptual constancy in vision related to smell?
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Vision: object is bigger, must be closer. Smell: object smells more intensely, must be closer.
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How is the type of smell (quality) encoded?
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Through a pattern of activity across a range of regions in the mucosa.
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What can you say about similar chemical structure and perception?
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Sometimes, chemcals are very similar in structure yet result in different perceptions. Sometimes, chemicals very different in structure but result in same perception.
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How is the smell threshold similar to ideal auditory and visual thresholds?
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We can perceive one molecule of mercaptan in a large number of molecules in air. Similar to perceiving one photon or tiniest vibration in air.
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What can you say about gender, age, and adaptation?
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Gender differences in smell perception, smell declines with age, adapt to prolonged stimulus.
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What did the experiment with episodic vs. laboratory odor find out?
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If people have a story or shock associated with odor, much more likely to remember it. Odor can serve as a very potent and long-lasting memory cue.
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What do releaser pheromones do?
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Produce an immediate and direct effect on the receive. E.g. female dog releaser hormone causes male dog to intiate mating behavior.
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What do primer pheromones do?
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Produce a long-lasting receptive state or physiological change (usually hormonal.
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What do marker pheromones do?
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Used by some mammals to mark their territories by leaving chemical trails.
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Alarm pheromones
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Pheromones that signal the presence of danger.
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What about pheromones in humans?
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Possible, but not confirmed. Women may synchronize their mentrual cycles via transmission of pheromones...evoluitionarily, regular mentrual cycles could increase chances of succesful conception.
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What is the common chemical sense?
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A system that serves as an irritant detector: stimulated by chemical irritants touching mucosal surfaces.
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What types of receptor cells are most likely used in the common chemical sense?
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Free nerve endings with simple binders.
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Where in the brain do taste and smell combine in flavor perception?
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The orbital-frontal cortex.
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What is the perception of taste also influenced by?
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The limbic system (emotion, hunger).
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