Nasal cavity: olfactory region
Although the organization of the olfactory region of the nasal cavity is similar to that of the non-olfactory region, important differences distinguish the two regions. In the olfactory region, the pseudostratified epithelium is much thicker and possesses bipolar neuronal cell bodies in addition to epithelial cells. Also, serous glands replace the mixed glands in the lamina propria. 400x
Olfactory epithelium >
Pseudostratified columnar epithelium of the olfactory region is much thicker than is respiratory epithelium. In addition to the epithelial cells usually seen, bipolar neurons are also present. Their nuclei are located in the middle of the epithelium with nuclei of supporting cells above and those of basal cells below the neuronal nuclei.
In addition to cilia associated with epithelial cells, the peripheral neuronal process of each bipolar neuron enlarges at the surface of the epithelium to form an olfactory vesicle from which multiple, lengthy, non-motile cilia project. These cilia act as receptor sites for olfactory stimuli.
Bowman's glands >
Serous glands of Bowman (blue arrows) fill the connective tissue lamina propria beneath the epithelium. These glands open onto the surface and keep the surface cleansed to receive new odors. One of their ducts (green arrows) is visible traversing the epithelium.
Sensory, cranial neurons are also present in the lamina propria. These neurons carry general sensory input as well as the special sense of smell.