Anatomy Tutorial: Olfaction & Gustation
\({\bf{Olfaction:}}\) sense of smell contains: > two sensory organs, located on either side of the nasal septum > an olfactory epithelium made of bipolar olfactory sensory neurons, supporting cells, basal epithelial cells > lamina propria, a layer of loose CT under the epithelium, containing olfactory glands, blood vessels nerves |dw:1540167252683:dw| > basic mechanism: nasal conchae produces turbulence, bringing olfactants in contact w/ olfactory mucus so it can diffuse and stimulate olfactory neurons
\({\bf{Olfactory~Nerve~Cells:}}\) > dendrites make a bulb that projects into nasal cavity > the bulb is the base for cilia which extend into the mucus > odorant binds to cilia --> depolarization --> action potential \({\bf{Olfactory~Pathways:}}\) > two neuron pathway - first-order neuron: leaves olfactory epithelium, becomes first cranial nerve - second-order neuron: synapse w/ olfactory cortex > **** travels to cerebral cortex without synapsing in thalamus *** > CNS interprets smell based on receptor activity
\({\bf{Gustation:}}\) sense of taste > gustatory epithelial cells: taste receptors, found on tongue, and portions of pharynx/larnyx > detects food molecules/dissolved chemicals and transmits information to gustatory cortex > tongue has epithelial projections (papillae) > each taste bud has gustatory epithelial cells, special epithelial cells, and basal cells > gustatory cells extends microvilli into taste pores |dw:1540168623080:dw| \({\bf{Gustatatory~Pathways:}}\) > three neurons > synapses in the medulla, thalamus, cerebral cortex > innervated by cranial nerves VII, IX, X |dw:1540168903407:dw| \({\bf{Taste~Pathways:}}\) - salty, sweet, sour, bitter, umami, and water receptors - higher sensitivity to unpleasant tastes for survival purposes
Adapted from Human Anatomy, Martini, et. al. 9th edition
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