Mitral and periglomerular cells are seen
in ?
a) Medulla
b) Olfactory bulb
c) Primary visual cortex
d) Geniculate body
Correct Answer - B
Ans. is ‘b’ i.e., Olfactory bulb
The sensory receptors for olfaction (smell) are located in the
olfactory mucous membrane. In human, the olfactory mucous
membrane (olfactory neuroepithelium) located in the roof of the
nasal cavity near the septum. Because of its location high in the
nasal cavity, the olfactory mucosa is not directly exposed to the flow
of inspired air entering the nose.
The olfactory mucosa contains olfactory receptors. The olfactory
receptors are unique in that the receptor cell itself is a neuron. The
olfactory receptor cell has cilia projecting in the nasal mucosa which
act as receptor for olfaction (These are dendrites of neuron/receptor
cells). The axons of olfactory neuron (olfactory receptor cells) form
olfactory nerve which passes through cribriform plate and terminates
in the olfactory bulb. In olfactory bulb axons of olfactory nerve
synapse with dendrides of mitral cells to form the olfactory glomeruli.
Mitral cells are the principal output neurons of olfactory bulb and
their axons form the olfactory tract.
The olfactory bulb also contains periglomerular cells, which are
inhibitory neurons and granule cells which have no synapse and
make reciprocal synapses with mital and tufted cells.
Like the taste fibers, olfactory tract also projects to the primitive parts
of the brain as well as the neocortex. The projections to the primitive
parts are principally to the pyriform area (olfactory cortex), amygdala
and entorhinal cortex, which in turn projects to the hippocampus.
The pathway to the neocortex involves a relay in the olfactory
tubercle, and then in the thalamus, the output of which projects to
the orbitofrontal cortex.