Term
| What are the four categories of chemoreceptors in taste and smell? |
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Definition
1.visceral chemoreceptors 2.gustatory receptors 3.olfactory receptors 4.chemosensitive endings |
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Term
| what three things is flavor a combination of? |
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Definition
1. direct chemical stimulation of taste buds on tongue 2. stimulation of olfactory receptors by vapours in food 3. stimulation of chemical receptors and somatosensory free nerve endings in mucous membranes of oral and nasal cavities - impt for texture, spiciness, temperature, texture of food |
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Term
| where are taste receptors located? |
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Definition
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Term
| what structures do taste buds sit on? |
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Definition
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Term
| what are the three kinds of papillae? |
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Definition
1. fungiform papillae -200-300 -contains 3-5 taste buds 2.foliate papillae -about 20 folds -contain 100-150 taste buds 3.circumvallate papillae -series of 8 or 9 -contain 250 taste buds |
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Term
| what type of cells are taste receptors? |
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Definition
| modified epithelial cells, but act like neurons |
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Term
| what are the five taste sensations? |
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Definition
salty - cation channels sour - cation channels bitter - G protein-coupled receptors --> cation channels sweet - G protein-coupled receptors --> cation channels umami(glutamate) - G protein-coupled receptors --> cation channels |
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Term
| how is the signal in taste receptor carried to neurons? |
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Definition
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Term
| which nerves transmit taste information? |
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Definition
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Term
| What structures does CN VII innervate? |
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Definition
soft palate via greater petrosal nerve anterior 2/3 of tongue from chorda tympani nerve Info goes to geniculate ganglion |
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Term
| what structures does the CN IX innervate? |
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Definition
posterior 1/3 of tongue, tonsils and pharynx info sent to inferior ganglion of IX (petrosal ganglion) |
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Term
| what taste structures does the CN X innervate? |
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Definition
epiglottis info sent to inferior ganglion of X (nodose ganglion) |
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Term
| what is the solitary tract nucleus? |
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Definition
The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX) and vagus (X) cranial nerves. from Wikipedia |
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Term
| where do secondary neurons from the solitary tract nucleus go? |
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Definition
1. reflex motor nuclei -from there to muscles involved in swallowing, salivation, coughing 2. to ipsilateral VPM of thalamus |
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Term
| where does information go after the VPM of thalamus? |
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Definition
1. central tegmental tract to gustatory cortex includes: insula medial surface of frontal operculum 2. from gustatory cortex to orbital cortex, hypothalamus and amygdala 3.collaterals along central tegmental tract to reticular formation |
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Term
| what are the sources of odourants detected by olfactory epithelium? |
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Definition
1. external environment through breathing or sniffing 2. vapours from food during eating (contributes to perception of flavour) |
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Term
| how often are olfactory receptor cells replaced? and by what are they replaced? |
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Definition
1-2 months by basal cells of olfactory epithelium |
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Term
| what type of cells are olfactory receptors? |
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Definition
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Term
| how are odourants detected? |
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Definition
olfactory vesicles have 10-30 immotile chemosensitive cilia odourants diffuse in mucous or are bound to odourant-binding proteins with the mucous axons of olfacotry receptors (unmyelinated) bundle into olfactory filia which pass through cribiform plate of ethmoid bone |
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Term
| how man different olfactory receptor neurons do we have? |
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Definition
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Term
what kind of receptors are olfactory receptors? |
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Definition
GPCR 2nd messenger system results in depolarization (CA2+, NA+, K+ influx, Cl- efflux) receptor potential adapts --> fading perception of odours |
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Term
| what cell types are seen in olfactory bulb? |
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Definition
1. mitral cells 2. granule cells 3. tufted cells |
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Term
| how are axons of the same receptor types organised? |
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Definition
| they are organised into specific glomeruli |
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Term
| what do mitral and tufted cells give collaterals to? |
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Definition
1. anterior olfactory nucleus 2. olfactory tubercle 3. PIRIFORM CORTEX 4. part of amygdala 5. periamygdaloid cortex 6. part of entorhinal cortex |
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Term
| where do projections of primary olfactory cortex go? |
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Definition
1. hypothalamus 2. hippocampus 3. amygdala 4. thalamus – dorsomedial nucleus connects olfactory bulb to olfactory association cortex (anterior insula adjacent to gustatory cortex) 5. directly to association cortex 6. orbital cortex |
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Term
| where is the association cortex for flavor located? |
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Definition
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Term
the association cortex for flavour recieves what kinds of inputs? |
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Definition
1. gustatory 2. somatosensory 3. olfactory 4. visual 5. limbic • all can modulate flavour |
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