Smell and Taste (Karius) Flashcards
what receptors have a high turnover rate, odorant or taste and what can effect them
both, chemotherapy
what is added to natural gas to alert us to the presence of it and what happens with age
mercaptan, sensiativty to this smell declines with age
what kind of receptors are odorant receptors
G-protein coupled that create cAMP to open cyclic nucleotide gated ion channel
-Gs or Golf
what happens if odorant persists for more than a few minutes
the sensitivity of the channel to cAMP is reduced decreasing Na+ and Ca++ entry
-AP potential is reduced
what happens when odorant concentration is really high
changes perceived smell because it starts to bind other receptors that have a low affinity for that odorant
what is TAARs receptors
activation does not necessarily lead to conscious awarenes of an order, instead produce physiologic/endorcine responses to pheromones
transmission to the brain of smell, neurons involved
axons of olfactory neurons pass through cribfriform plate and synapse on neurons of the olfactory bulb
layers of the olfactory bulb
granule cell layer mitral cell layer external plexiform layer glomerular layer olfactory nerve layer
cribriform plate
olfactory epithelium
which cels of the olfactory bulb are not directly activated by olfactory cells
the granule cells
the olfactory neruons will synapse with what cells in the glomeruli
mitral cells
tufted cells
periglomerular cells
which cells of the glomeruli have axons going to the cortex and which have cell axons that stay in the olfactory bulb?
mitral cells and tufted cells have axons go to cortex (axons join olfactory tract)
periglomerular cell axons will remain in the olfactory bulb
role of periglomerular cells
release GABA at their synaptic contact with other glomeruli and inhibit the activity from those glomeruli
function of the granular cells
also release GABA at their synaptic contacts but they synapse with mitral and tufted cells
-also increase specifictiy of message going to olfactory cortex
first possible synapse in olfactory cortex
in anterior olfactory nucleus
-synapses relay info to contralateral side and axons also continue on the ipsilateral side
what are the 2 main parts of the olfactory cortex most important in smell perception
piriform cortex
lateral entorhinal cortex
where does the entorhinal cortex project and what is its function
hipposcampus and memory function
where does the piriform cortex project to and what is the function
lateral hypothalamus and control of appetite
also to medial orbitofrontal cortex via the thalamus to provide information that is used to identify the flavor of foods
where does the olfactory cortex send input back to
the olfactory bulb/epithelium to modify receptor responses to odorants
when is sour taste produced
when hydrogen ion enters the taste bud via a hydrogen-ion channel
how is salty taste produced
when sodium or calcium ion enter the taste bud via a sodium or calcium channel
what kind of receptor is the umami taste receptor
metabotropic glutamate recepter activated by glutamate
gustary input synapses
NTS
thalamus
gustatory cortex (includes anterior insular cortex)
synapse for gustary at thalamus goes where next
cortex and the lateral hypothalamus
-input has significant impact on appetite
what does the perception of flavor require
gustatory input from the gustatory cortex
olfactory input from olfactory cortex (especially piriform cortex)
somatosensory info from the mouth
