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35 Cards in this Set
- Front
- Back
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What are the first order neurons in the smell pathway?
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Primary olfactory sensory neurons located in neuroepithelium
unmylinated axons form olfactory nerve bundles which project to olfactory bulb |
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Where do the second order neurons in the smell pathway project to/from?
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Project from olfactory bulb
Project to : 1. Piriform Cortex (Uncus) 2. Amygdala |
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What is the function of the piriform cortex (uncus)?
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Smell perception
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What is the function of the amygdala?
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odor associated emotions
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The accessory system is important in what and uses what "organ"
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Important in detecting pheromes
Uses Vomeronasal Organ |
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What 3 cell types are found in the olfactory neuroepithelium?
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1. Olfactory Sensory Neurons
2. Supporting Cells 3. Basal Cells |
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What is the cellular anatomy of the Olfactory Sensory neurons?
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Ciliated Bi-polar neurons
Regenerate throughout life |
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What is the function of basal cells?
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Stem cell life - give rise to new OSN's and supporting cells
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What are the steps in olfactory signal transduction?
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1. Odor molecule binds to GPCR
2. Activation of olfactory G-Protein (GOLF) 3. cAMP created, opens cyclic nucleotide gated (CNG) channel, which allows Na/Ca to flow IN 4. Ca opens Cl channels and allows Cl- to flow out End result is depolarization of cell |
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What is unique about odorant receptor gene sperfamily?
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It is the LARGEST in the genome
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One OSR expresses how many receptors?
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Only one
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Does one OSR only respond to ONE odorant?
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NO, can respond to multiple (provided they have similar structure)
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Does one odorant only bind to one receptor?
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NO, binds to multiple
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How are odor quality and intensity encoded?
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POPULATION ENCODING- By combination of multiple receptors/neurons
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Where do the aon terminals of the sensory neurons synapse with the dendrites of olfactory bulb neurons?
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Glomeruli
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What are the 3 major cell types in the olfactory bulb?
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1. Mitral/tufted cells - receive inputs from OSNs; send axons to higher cortical areas
2. Periglomerular cells - modulate/temper inputs to mitral/tufted cells 3. Granule Cells - modulate/temper outputs from mitral/tufted axons to cortical regions |
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Which 2 cell types in the olfactory bulb are inhibitory?
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Peroglomerulare and Granule cells
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What serve as the anatomical and functional units in the olfactory bulb?
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Golmeruli
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What is the output of mitral/tuftedd cells?
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Sends its ONLY primary dendrite into a single glomerulus, which is innervated by ~25 mitral/tufted cells
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Is odor representation distributed in the pifiform cortex spatially?
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NO - random
Different than visual, auiditory, and somatosensory system |
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What are the 5 modalities of taste?
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1. Salty
2. Sour 3. Bitter 4. Sweet 5. Umami |
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What is the anatomy of taste buds?
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Taste cells are clustered in taste buds
Taste cells extend microvilli into taste pore Taste cells are innervated by sensory neurons at the basal pole |
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Taste information is sent to the brain via which 3 cranial nerves?
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1. IX
2. VII 3. X |
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Sensory fibers from the taste cells enter what tract and synapse on what nuclei?
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The SOLITARY tract and nuclei
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The solitary nucleus axons project to where?
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Project to VPM, which relay taste information to the ipsilateral, primary gustatory cortex (INSULA)
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The modalities of salty and sour are mediated by what mechanism?
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ION CHANNELS
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What is the ion channel for salty tastes?
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Na salts cause Na influx through the epithelium sodium channel (ENaC) which depolarizes the cell
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What is the ion channel for acidic/sour tastes?
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Passage of H+ ions through a type of TRP (transient receptor potential) channel causes depolarization in cell
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The modalities of Sweet, umami, and bitter are mediated by what?
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GPCRs
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Sweet cells express what receptors?
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T1R2 + T1R3
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Umami cells express what?
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T1R1 + T1R3
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Bitter cells express what?
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T2Rs
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Each taste cell expresses how many receptors?
Is tuned to how many modalities? |
Many receptors BUT just one modality
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Taste information is encoded how?
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A "labeled line" scheme - based on what type of cell is activated, brain deduces what tastants are encountered
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How is the insula organized?
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Spatially, supporing a labeled line hypothesis
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