Term
| 3 types of papillae (with locations/buds amount) |
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Definition
1. Fungiform (anterior, few taste buds)
2. Foliate (posterior lat edge, 12-600 buds)
3. Circumvillate (back portion. 250 buds) |
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Term
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Definition
| dissolved ion or molecule that stimulates taste receptor proteins |
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Term
| Taste receptor cell (250 or so in each taste bud) |
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Definition
Non-neuronal, polarized epithelial cell
Apical surface has:
-microvilli that project into taste pore)
-taste receptor proteins
Basal surface has: synapses on sensory afferents
-each cell has a week lifespan |
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Term
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Definition
how a stimulus in the environment causes and electrical response in a sensory receptor cell
-transduction is how a TASTANT leads to a RECEPTOR POTENTIAL (deoplarization) in the TASTE RECEPTOR CELL.
-depolarization causes neurotrans release (ATP,5HT) from the TRC, causing sensory axon to fire action potentials |
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Term
| Transduction of salt taste: ion channel |
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Definition
1. Tastant (Na+) enters through amiloride-sensitive Na+ channels (not voltage gated), causing depolarization
2. Voltage-gated ion channels open leading to neurotransmitter release |
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Term
| Transduction of sour taste: ion channel |
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Definition
1. tastant (H+) enters through some type of cation channel (opens TRPP or closes K+) causing deoplarization
2. Voltage-gated ion channels open leading to neurotransmitter release. |
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Term
| transduction of bitter, sweet and umami tastes: G-protein coupled receptors |
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Definition
1. Tastant (quinine, glucose, or glutamate binds GPC receptor)
2. G-protein GUSTDUCIN is activated
3. Beta-gamma subunits of gustducin stimulate phospholipase C
4. phospholipase C hydrolizes PIP2 to IP3 and DAG
5. IP3 activates TRP channel (TRPM5)
6. increased intracellular Ca2+ depolarizes cell
7 neurotransmitter is released |
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Term
| Taste receptor proteins: the G-protein coupled receptor type |
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Definition
BITTER: 30 different types of bitter receptors (T2Rs), receptors consist of two T2R proteins
SWEET/UMAMI: are heterodimers (made up of two diff subtypes), T1Rs
Sweet=T1R2+T1R3
UMAMI=T1R1+T1R3 |
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Term
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Definition
| TRCs of one kind: 1 TRC has one receptor type which releases to one sensory axon |
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Term
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Definition
multimodal TRCs: 1 TRC has many receptor types to 1 sensory neuron
- or more than one kind of TRC to 1 sensory neuron |
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Term
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Definition
-Cranial nerves V11, IX, and X carry taste signals
-The axons project ipsilaterally to the gustatory nucleus in the medulla.
-gustatory nucelus axons synapse on cells in central posterior medial (VPM) of thalamus
-VPM neurons project to gustatory cortex and frontal cortex |
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