Medical neuroscience

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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