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29 Cards in this Set
- Front
- Back
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4 types of chemoreceptors |
1.taste receptors 2. olfactory receptors 3. visceral chemoreceptors 4.chemosensitive endings - have warning and reward fx |
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visceral chemoreceptors |
detect O2, glucose, hormone levels, etc for homeostasis, monitor internal environment |
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chemosensitive endings |
mediate common chemical sense- heat of chili peppers, cool of menthol, sting of amonia |
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taste |
detection of chemicals in water solution. chemical detection of sweet, salty, sour, bitter and savory (umami) |
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flavor |
the combination of smell, taste and common chemical sense (pungency, spiciness) and somatosensory (temp and texture) |
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papillae |
bumps and folds of tongue, 3 types 1. fungiform 2. foliate 3. vallate or (circumvallate) |
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fungifrom papillae |
located at the tip and sides of tongue CN III each contain 3-5 taste buds |
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foliate papillae |
located on posterior and sides of tongue CN VII and IX |
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vallate papillae |
-series of 8 or 9 papillae arranged in a V shape on the post 1/3 of tongue - CN IX -each contain about 250 taste buds |
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taste buds |
modified spindle shaped epithelial cells with neuron like properties. -lifespan of a couple weeks
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how tastebud work? |
microvilli processes extend thru a tastepore, here they are exposed to the chemical stimuli dissolved in the saliva, which produce receptor potentials. chemical synapses are made on the end of cranial nerves. |
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sweet |
sugars, saccharin, alcohol, and some amino acids |
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sour |
H+ |
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salt |
metal ions |
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bitter |
alkaloids such as quinine and nicotine |
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umami |
savory - like grilled meat. aminoacids glutamate (MSG) and aspartate |
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salt transduction |
cation channels in tastebuds allow Na+ influx which depolarizes the cell. influx Na+ correlates directly to amount of Na+ in saliva |
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sour transduction |
usually due to acids (H+) - open pH sensitive cation channels and cause depolarization |
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sweet, bitter and umami |
G-coupled protein channels cause cation channels to open and the cell to depolarize |
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taste pathway |
tastebuds synapse onto cranial nerves--> solitary tract--> solitary nucleus-->B/L to VPM of thalmus-->I/L gustatory cortex in the insula |
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smell |
-detection of airborn chemicals -peripheral receptors in olfactory epithelium in roof of nasal cavity -innervated by CN I -CN V in olfactory epithelium for common chemical sense e.g. amonia |
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olfactory receptors |
-true bipolar neurons -odors are caught in a layer of mucus via cilliary hairs which are teh olfactory vessicle
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pathway for smell |
olfactory vesicle (dendritic end on receptor cell lives in snot)-->receptor cells in olfactory epithelium-->unmylinated axons collect into olfactory filia-->filia pass thru holes in the olfactory plate that synapse with the olfactory bulb (the first CN) |
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smell transduction |
-binding of oderatant causes cation channels to open and depolarization, if local potential is high enough AP are sent. the cells quickly adapt to prolonged stimuli |
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olfactory pathway post endering bulb |
olfactory nerves --> lateral olfactory tracts--> to uncus --> 1* olfactory cortex (& amygdala)--> DM--> olfactory association area (in frontal lobe/insula next to the gustatory cortex)--> many places |
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ansomnia |
loss of smell |
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conductive deficits |
-blockage of nasal cavity/ olfactory epithelia -causes include septal deviations, nasal polyps, inflammation and allergies |
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sensorineural deificts |
-damage to neural components -usually due to head injuries where nerve is damaged at the cribiform plate -or neurodegenerative diseases like parkinson's or alzheimers |
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seizure in uncus |
-can cause olfactory hallucinations and behaviors like smacking lips |
