olfactory Flashcards
Axons from olfactory receptors are among the _____ and _____
thinnest and slowest
Describe an olfactory receptor
A small bipolar neuron
Dendrite ends in olfactory vesicle, from which 10-30 cilia spread over the surface in a layer of mucus secreted by Bowman’s glands
Stimulate chemosensitive cilia
Unusual among human neurons-replaced throughout life, 1-2m life
Axons from olfactory receptors collect into a series of bundles (only about 20) called ___________, pass through holes in __________ of ethmoid bone
olfactory fila
cribiform plate
olfactory receptor axons end in
olfactory bulb
olfactory fila make up
cranial nerve I
taste and smell:
conscious chemical sensation
olfaction:
detects volatile chemicals (odorants) drawn into nasal cavity
humans can detect about ________ different odors
10,000
peripheral origin of olfactory system
olfactory epithelium
Patch in roof of nasal cavity, bilateral
Contains 3 million receptor cells, supporting cells, bowman’s gland ducts, sensory endings from CN V (irritants)
Olfactory epithelium
_________ develops as an outgrowth of telencephalon
olfactory bulb
Olfactory bulb and tracts reaches
ipsilateral hemisphere with no relay in thalamus
olfactory fibers sort in
bulb
each type of olfactory receptor sends an axon to one _________ of a mitral cell even though these cells are intermingled in the olfactory epithelium
glomerulus
olfactory bulbs project to
olfactory cortex
axons of mitral and ______ cells in tract
tufted
Collaterals to anterior olfactory nucleus
thought to regulate sensitivity of olfactory bulb
fibers project to both bulbs
cross midline in anterior commissure
some fibers in tract end in
olfactory tubercle
most fibers turn laterally and end in
lateral olfactory pathway
olfactory bulb projections end in two general areas
primary olfactory cortex
amygdala
primary olfactory cortex consists of
cortex near lateral olfactory tract, aka piriform cortex
cortex covers amygdala, periamygdaloid cortex
small part of hippocampal gyrus
olfactory information sent to
hypothalamus, thalamus, hippocampus, orbital cortex, amygdala
olfactory association cortex
orbital surface of frontal lobe and anterior insula
