1. Olfactory pathway
Domina Petric, MD

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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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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
Odorant molecules can reach the olfactory receptors via a passive pathway or an assisted pathway. 
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The passive pathway
Molecules reach the olfactory mucosa via inhaled air. 
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The assisted pathway
The molecules attach to an olfactory binding protein that transports them directly to the olfactory receptors.
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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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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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Limbic system
The limbic system is involved in the perception of emotions and is responsible for the "affective" component of smell.
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Literature
(Neuroscience, 2nd edition)
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