Olfactory Flashcards
olfaction: the sensation of smell, via detection of _____ in the air that we breathe
odorants
olfactory receptors are distributed within the ______ lining an upper portion of the nasal cavity
olfactory epithelium
a stream of inhaled air is circulated past the olfactory epithelium, which is coated with a ______
mucus lining
______ stimulation of odorant receptors triggers bioelectric signaling (trains of action potentials) from the olfactory sensory neuron
Ligand
______ projecting a “dendrite” into the olfactory epithelium, and an axon which projects into the olfactory bulb
bipolar neurons,
the human genome contains ~_____odor receptor genes
1000
_____ of the 1000 odor receptor genes code for receptor proteins*
400
odorant receptors belong to the ______ , with each presenting a unique and specific sequence and structural motif
G protein-coupled superfamily
Odorants function as ligands which bind to olfactory receptors, to trigger the opening of ______ , causing the sensory neuron to depolarize
ion channels
T/F odorant receptors are rapidly adapting
True
Encoding the intensity of smell: The strength of the neuronal response ) will vary in proportion to the ______ of the odorant
concentration
Each olfactory neuron will express ______ of the ~400 distinct receptors encoded by the human genome
just one
How many distinct odorant can humans discriminate?
10,000 +
What are the two key characteristics of receptor odorant specificity:
any one receptor will respond to more than just one odorant
any one odorant will stimulate more than just one receptor
Individual odorants are detected by an array of receptors, that generate a ______ of signals
distinctive pattern
_______ will generate unique patterns of receptor activation that enable coding of individual odorants
combinatorial coding
Primary axons from the olfactory receptors project into the _____ where they synapse upon second order neurons
olfactory bulb
axons from olfactory sensory neurons synapse upon dendrites of olfactory bulb neurons within distinct bundles of neuropil called ______
glomeruli
______ & ____ cells are relay neurons that project axons towards the olfactory cortex
mitral & tufted
_______ cells are interneurons that encircle the glomerulus
periglomerular cells
Where does integration and processing of the primary afferent signals arising from the olfactory receptors take place?
Olfactory Bulb
inputs that converge upon one particular _____ appear to all derive from just one particular type of receptor
glomerulus
