Term
| olfactory receptor neurons (ORN) |
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Definition
-neuronal cells (unlike taste cells)
-life cycle of 4-8 weeks (unusual for adult neurons) |
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Definition
-detoxify toxins in mucus
-contribute to mucus |
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Definition
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Term
| olfactory receptor neuron properties |
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Definition
-bipolar shape
-dendrite (1 per ORN), end in a knob, several cilia from one knob
-Axon: unmyelinated, collectively called cranial nerve (but not bundled physically) |
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Term
| olfactory transduction (oderant reacting with ORN): g-protein coupled |
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Definition
1. odorant binds to odorant receptor
2. olfactory G-protein (g_olf) activated
3. Adenyl cyclase activated
4. cAMP synthesized
5. cAMP binds to cyclic nucleotide gated (CNG) channels
6. Influx of Na+ and Ca2+
7. Ca2+ binds to Ca2+ activated Cl- channels
8. membrane depolarization |
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Term
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Definition
-g protein coupled
-7 TM domains
-odorant binding occurs in EC domain
-g-protein interaction occurs via intracellular c-terminal
-most ORNs express a single odorant type |
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Term
| each ORN is broadly tuned |
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Definition
-one odorant can activate more than one type of odorant receptor
-CNS has to compare the pattern of activity for the different ORN types |
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Term
| odor perception (population coding) |
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Definition
| a pattern of activity across unique ORN types |
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Term
| olfactory pathway (nose to brain) |
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Definition
-ORNs axons project to olfactory bulb via small bundles (cranial nerve I)
-ORNs synapse onto mitral cells in glomeruli
-Mitral cell axons form a bundle (laterl olfactory tract) which projects to: olfactory cortex, olfactory tubercle-MDN of thalamus-orbitofrontal cortex |
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Term
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Definition
| the inability to detect a common odor |
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