PURVES NEUROSCIENCES CHAPTER 15: THE CHEMICAL SENSES
Odorants interact with olfactory receptor neurons found in the olfactory epithelium which lines the
interior of the nose.
Cribiform plate separates the olfactory epithelium from the brain.
Axons project through the cribiform plate directly to the neurons in the olfactory bulb. The olfactory
bulb sends projections to the pyriform cortex, as well as other structures in the forebrain via the
olfactory tract (an axon pathway).
Olfactory sensory information is relayed to and then processed in the pyriform cortex a three-
layered archicortex dedicated to olfaction.
The pathway cribiform plate pyriform cortex bypasses the thalamus, HOWEVER: olfactory
information from the pyriform cortex is relayed to the thalamus en route to association in the
neocortex where further processing occurs.
Anosmias = chemosensory deficits.
Bowman’s glands = secretory specializations that produce mucus, are distributed throughout the
olfactory epithelium.
Other cells present in the olfactory epithelium:
- Basal cells
- Sustentacular (supporting) cells contain enzymes that catabolize organic chemicals and
other potentially dangerous molecules.
Nasal mucosa = mucus layer and epithelium with neural and supporting cells.
The neural portion of the olfactory epithelium is primarily defined by the olfactory receptor neurons
(ORNs) bipolar cells.
Olfactory ensheathing cells = glial cells that surround axons in the olfactory nerve and bulb.
Odorants interact with olfactory receptor neurons found in the olfactory epithelium which lines the
interior of the nose.
Cribiform plate separates the olfactory epithelium from the brain.
Axons project through the cribiform plate directly to the neurons in the olfactory bulb. The olfactory
bulb sends projections to the pyriform cortex, as well as other structures in the forebrain via the
olfactory tract (an axon pathway).
Olfactory sensory information is relayed to and then processed in the pyriform cortex a three-
layered archicortex dedicated to olfaction.
The pathway cribiform plate pyriform cortex bypasses the thalamus, HOWEVER: olfactory
information from the pyriform cortex is relayed to the thalamus en route to association in the
neocortex where further processing occurs.
Anosmias = chemosensory deficits.
Bowman’s glands = secretory specializations that produce mucus, are distributed throughout the
olfactory epithelium.
Other cells present in the olfactory epithelium:
- Basal cells
- Sustentacular (supporting) cells contain enzymes that catabolize organic chemicals and
other potentially dangerous molecules.
Nasal mucosa = mucus layer and epithelium with neural and supporting cells.
The neural portion of the olfactory epithelium is primarily defined by the olfactory receptor neurons
(ORNs) bipolar cells.
Olfactory ensheathing cells = glial cells that surround axons in the olfactory nerve and bulb.
