Olfactory system Flashcards
what are the components of the olfactory system
olfactory: mucosa, nerve, bulb, tracts, cortex
where is the olfactory mucosa located
located in superior aspect of each nasal fossa (spenoethmoid recess), 2.5 cm square of specialized mucosa, extends onto the median nasal septum and lateral wall
what type of epithelial cells line the olfactory mucosa
PSCC
what are olfactory glands
bowman’s gland, found beneath epithelium, secretes fluid onto surface of mucosa to dissolve odorant chemicals
what are olfactory cells
bipolar neurons that are modified to serve as olfactory receptor cells and conduct impulses, few month turnover, axons are unmyelineated (CN1)
what are olfactory nerves
formed by axons of olfactory cells, bundles of axons enter cranial cavity through cribriform foramina of ethmoid bone, axons enter olfactory bulb and terminate in clusters of synaptic endings called glomeruli
what are olfactory bulbs
extension of brain that is along ventral surface of frontal lobe, mitral cells, tufted cells
what are mitral cells
dendrites arborize within glomeruli with olfactory cell axons, one mitral cell communicates with several olfactory cells, axons comprise most of fibers of olfactory tract and project centrally in brain
what are tufted cells
another type of neuron found within olfactory bulbs, axons of these cells travel through olfactory tracts
what are the association neurons of the olfactory bulb
include periglomerular cells, granule cells, serve to modify olfactory info before reaching the cerebral olfactory areas
what is the olfactory tract
most fibers are from mitral cells, but some from tufted cells
where do olfactory tract fibers lead to
olfactory trigone at base of brain, which splits into lateral olfactory stria and medial olfactory stria
where do most of the olfactory tract transverse to
lateral olfactory stria to the lateral olfactory area of the cerebrum
T/F some fibers make up an intermediate olfactory stria and terminate in the anterior perforated substance
true
T/F although often observed as a ridge of tissue, the “medial olfactory stria” does not include olfactory tract fibers to the septal area as originally thought
true
what are the cerebral olfactory areas
lateral olfactory area and anterior perforated substance
what does the lateral olfactory area receive input from
the olfactory bulbs through fibers of the lateral olfactory stria
what areas are included in the lateral olfactory area
uncus, limen insula, part of amygdala
what areas comprise the primary olfactory area
uncus, limen insula, part of amygdala (largely in temporal lobe)
what is the primary olfactory area responsible for?
subjective appreciation (awareness) of an olfactory stimulus
what is the olfactory association area
cortical areas adjacent to the primary olfactory cortex: permits the identification of the qualities of odors and also the significance
what do the lateral olfactory areas (with hippocampus & amygdala) serve as?
important limbic system structures–allow for odors to influence memories, emotions, and visceral responses
where is the anterior perforated substance positioned
between lateral and medial olfactory stria, area forms intermediate olfactory area
