206
UNIT 3
Organ Systems
Ducts of
Ducts of
Bowman glands
Bowman glands
Connective
Connective
tissue
tissue
Basal cells
Basal cells
Blood vessel
Blood vessel
Nuclei of
Nuclei of
olfactory cells
olfactory cells
Olfactory
Olfactory
epithelium
epithelium
Lamina
Lamina
propria
propria
Cilia
Cilia
Basal cells
Blood vessel
Connective
tissue
Ducts of
Bowman glands
Olfactory fila
Olfactory fila
(axons with nuclei of
(axons with nuclei of
unmyelinated Schwann cells)
unmyelinated Schwann cells)
Olfactory fila
(axons with nuclei of
unmyelinated Schwann cells)
Nuclei of
olfactory cells
Olfactory
epithelium
Lamina
propria
Cilia
Nuclei of
Nuclei of
supporting cells
supporting cells
Nuclei of
supporting cells
Bowman
Bowman
glands
glands
Bowman
glands
B
Figure 11-4B.
Olfactory mucosa, nose.
H&E,
3
326
Olfactory mucosa
is composed of specialized
epithelium (
olfactory epithelium
) and
lamina
propria
with
Bowman glands
, nerve axons
(
olfactory ±
la
), and
blood vessels
. The olfac-
tory epithelium looks like other pseudostrati-
F ed columnar epithelium but contains different
types of cells:
olfactory cells
(
receptor neurons
),
supporting
(
sustentacular
)
cells
, and
basal cells
.
Olfactory receptor neurons are bipolar cells with
long, nonmotile cilia, which function as recep-
tors for odorants. Supporting cells are colum-
nar shaped; their nuclei are dark and ovoid and
are positioned in the apical region of the cells.
Microvilli and a terminal web of the supporting
cells may be seen at the electron microscopy level.
The function of the supporting cells is to provide
mechanical support; they may also be involved
in binding or inactivation of odorant molecules.
Basal cells are short cells with round nuclei. They
lie in a single layer at the basal region of the epi-
thelium, serve as stem cells, and are capable of
regenerating into the other types of cells in the
epithelium. The lamina propria of the olfactory
mucosa contains Bowman glands,
olfactory ±
la
(collective unmyelinated axons), and blood ves-
sels. Bowman glands are serous glands, which
release a watery secretion onto the surface of the
epithelium. These watery secretions (containing
water-soluble proteins) serve to bathe the surface
of the olfactory epithelium and help trap and dis-
solve odorant molecules. The olfactory F
la are
axons of the olfactory receptor neurons.
Figure 11-4A.
A
representation
of
olfactory
mucosa.
The
olfactory mucosa
is located in the roof of the
nasal cavity (±ig. 11-1); it is composed of
olfactory
cells
(olfactory receptor neurons),
supporting cells
,
and
basal cells
in the epithelium, and of
olfactory
± la
(unmyelinated axons) and
Bowman glands
in the
lamina propria. Bowman glands release their product
onto the surface of the epithelium via ducts. The main
function of the olfactory mucosa is to detect odor.
Odorant molecules come into contact with the surface
of the olfactory epithelium in the nasal cavity and bind
to receptors on the cilia of the olfactory cells. Olfac-
tory cells transmit signals through the olfactory F
la to
the olfactory bulb and to the olfactory centers of the
central nervous system. Olfactory neurons are able to
proliferate after being damaged.
T. Yang &D. Cui
Olfactory cell
(olfactory receptor
neuron)
Duct of
Bowman gland
Basal cell
Olfactory fila
(unmyelinated axons)
Bowman gland
Fibroblast in
connective tissue
Supporting cell
A
Clinically, loss of smell is called
anosmia
, and
decreased sensitivity to odorants is called
hyposmia
.
These symptoms are often associated with upper air-
way infections.
previous page 221 Dongmei Cui -  Atlas of Histology with Functional and Clinical Correlations 2011 read online next page 223 Dongmei Cui -  Atlas of Histology with Functional and Clinical Correlations 2011 read online Home Toggle text on/off