The olfactory epithelium contains olfactory receptor neurons that detect scents. These neurons have cilia at their ends that contain olfactory receptors which transduce scents. When scents bind to receptors, it creates an electrical signal that travels along the neuron's axon to the olfactory bulb. The olfactory bulb then sends this signal to regions of the brain involved in smell perception and the limbic system.

1. Olfactory
pathway
Domina
Petric, MD

2. Introduction
• The olfactory mucosa contains
the olfactory receptor neurons that are
responsible for scent transduction.
• The transduction occurs in the olfactory
receptors located on cilia at the ends of
the olfactory receptor neurons.
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3. The olfactory epithelium
• The olfactory epithelium includes several
distinct cell types.
The most important of these is the olfactory
receptor neuron:
• a bipolar cell that gives rise to a small in
diameter, unmyelinated axon at its basal
surface
• axon transmits olfactory information centrally
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4. The olfactory cilia
• At its apical surface, the receptor neuron
gives rise to a single process.
• The process expands into a protrusion from
which several microvilli, olfactory cilia,
extend into a thick layer of mucus.
• Two other cell classes are also in the
olfactory epithelium: basal cells and
sustentacular (supporting) cells.
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5. The oflactory receptors
• Olfactory receptors are protein
molecules attached to the olfactory
receptor neurons.
• There are about 1,000 kinds of olfactory
receptors.
• All the olfactory receptors are the same
on each olfactory receptor neuron.
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6. Passive vs. assisted pathway
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7. The passive pathway
Molecules reach the
olfactory mucosa via
inhaled air.
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8. The assisted pathway
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9. The electrical signal
The electrical signal is sent
via the axons of the olfactory
neurons to structures
called glomeruli on the left
and right olfactory bulbs.
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10. http://archive.cnx.org
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11. The olfactory pathway
• Information is conducted from the
olfactory bulbs by the lateral olfactory
tract to the primary olfactory cortex.
• it goes to the thalamus (mediodorsal
nucleus) and on to the orbito-frontal
cortex.
• Here the conscious smell perception
occurs.
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12. Limbic system
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13. Literature
•http://www.ucalgary.ca
•http://archive.cnx.org
•https://www.ncbi.nlm.nih.gov/b
ooks/NBK10896/ (Neuroscience,
2nd edition)
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