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20 Cards in this Set
- Front
- Back
What provides friction that helps the tongue to move objects around in the mouth
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Filiform
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What contains about 5 tastbuds; scattered over entire surface of tongue
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Fungiform
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Containes about 100 taste buds
-Largest of papillae -7-12 form an inverted V at back of the tongue |
Circumvallate
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Supporting Cells
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-Form bulk of taste bud.
-Insulate receptor cells from each other as from surrounding tongue epithelium |
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Basal Cells
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Divide and differentiate into supporting cells >>> new gustatory cells
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What role do microvilli play in detecting taste?
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Long microvilli called taste hairs project through small opening.
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What 3 processes must happen in order for a taste to be detected?
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1. Chemicals dissolved in saliva come in contact with taste hairs>>bind to receptor proteins of the gustatory cells
2. Differet taste involves different receptors. -Depolarization of cell membrane as a result of chemically gated ion channels opening up or -G proteins>use secondary messengers to produce their effects. (Transmits info to nucleous to stimulate) 3. Results in neurotransmitters released by receptor cell>>Action Potential of the afferent fiber. -Threshold for receptor stimulation varies for each of the primary taste senstations. -Taste receptors respond more quickly to unpleasant that pleasant stimuli |
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What is the gustatory pathway?
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Taste buds are monitored by Cranial nerves Vii, IX, and X.
-Facial nerve - monitors all teh taste buds from anterior 2/3>tip of tongue>circumvalllate b. Glossopharyngeal - monitors posterior 1/3 of tongue & circumvallate C. Vagus - Innervates taste buds scattered on pharynx & larynx 2. Sensory afferents carried by these cranial nerves synapse in Medulla Oblongata 3. Postsynaptic joins someatic axons that carry infomation on touch, pressure, prorioception>>Thalmus 4. Another synapse in thalamus>gustatory center |
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Which reflexes are triggered by taste?
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-Increase in saliva and gastic juices
-Gaggins or reflexinve vomiting |
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What is gustatory discrimination?
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4 primary taste - sweet, sour, salty, & bitter
-Taste receptors differe in their sensitivity to tastes. Salty and Sweet --> anterior (tip) of tongue Sour and Bitter --> posterior (back) of tongue |
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Umami
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Pleasant taste charachteristic of beef broth, chicken broth, and parmesan cheese; found in circumvallate papillae
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Water
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Water receptors in phrarynx sensory output of these receptor.
Hypothalamus - affects systems involved ini H2O balance |
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What is the location and structure of olfactory epithelium?
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Contains olfactory receptors, supporting cells & basal cells.
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Supporting cells (Olfactory epithelium)
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Surround & cushin olfactory receptor cells
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Basal Cells/stem cells (Olfactory epithelium)
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Found at base of epithelium; divide and differentiate into supporting cells or new olfactory receptor cells.
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Olfactory receptor cells.
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-highly modified neurons - thin apical dendrite > ends in a knob > several long cilia radiate from knob > OLFACTORY CILIA
-Olfactory cilia - increases receptive surface area; covered within a thin layer of mucus; mucus traps & dissolves airborne odor moleculese - mucus renewed continuously (produced by supporting cells & glands in underlying c.t.) -unmyelinated axons of olfactory receptor cells form fiber bundles >>>Olfactory nerve -bundles project through openings in cribiform plate - bundles synapse in olfactory bulbs |
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Trace the olfactory pathway
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-Odor molecules come in contact with olfactory cilia
-Dissolved chemicals - stimulates olfactory cilium membrane > opens Na+ channels -Depolarrization>action potential>impulse transmitted along the axons of receptor cells -Axon of receptor cells come together > form olfactory nerve fiber bundles -Synapse in olfactory bulbs with mitral cell (type of neuron) -mitral cells are activated>impulses flow from olfactory bulbs via olfactory tracts to: Olfactory cortex and Hypothalamus emotional aspects of smells are analyzed & responded to) |
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Discuss the relationship between granule and mitral cells.
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Mitral cells are second-order neurons. Granule cells inhibit mitral cells so that only highly excitatory olfactory impulses are transmitted.
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Discuss the emotional aspects of smell
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-Olfactory bulbs - house granule cells that inhibit mitral cells(so that only highly excitatory olfactory impulses are transmitted) - granule cells allow employees of Bondi's island to still enjoy thier lunch.
-Aromas of food are perceived differently (starving vs. just eaten) -Smells associated with danger triggers SNS fight or flight response. -Appetizing odors - increase salivation & stimulates digestive tract Unpleasant odors - trigger protective reflexes > sneezing, coughing. |
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Explain olfactory discrimination
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-Olfactory system can make subtle distinctions among 2000-4000 chemicals
*no apparent structural differences exist amoung the olfactory receptor cells *at least 50 primary smells *not completely understood>appears the CNS interprets each smell on the basis of the overall pattern of receptor activity *some smells are detected in very small concentrations (ex. beta-mercoptan (added to natural gas) |