Taste and smell." Gustatory and Olfactory Pathways
1. Taste and Smell
Gustatory / Olfactory pathways
Daniel Vela-Duarte, MD
Department of Neurology
Loyola University Medical Center
July 2012
2. Smell.
It's a warning system to identify
potentially toxic food or noxious
chemicals.
Contributes to various life
qualities, provides awareness of
many pleasurable
sensations, including
appreciationof certain foods and
beverages and other pleasures.
6. Olfactory impulses reach
the cerebral cortex without
relay through the thalamus.
Olfaction is unique among
sensory systems. From the
prepiriform cortex fibers
project to the neighboring
entorhinal cortex and the
medial dorsal nucleus of
the thalamus.
The amygdaloid nuclei
connect with the
hypothalamus and septal
nuclei.
7.
8. Clinical Manifestations of
Olfactory Lesions
Quantitative abnormalities:
loss or reduction of the sense of smell
(anosmia, hyposmia) or, rarely, increased olfactory
acuity (hyperosmia)
Qualitative abnormalities:
distortions or illusions of smell (dysosmia or
parosmia)
Olfactory hallucinations and delusions caused by
temporal lobe disorders or psychiatric disease
Higher-order loss of olfactory discrimination (olfactory
agnosia)
9. Clinical presentation
Bilateral anosmia is a common complaint, and
the patient is usually convinced that the sense of
taste has been lost as well (ageusia).
Parosmia may also be a troublesome symptom
in middle-aged and elderly persons with a
depressive illness, who may report that every
article of food has an extremely unpleasant odor
(cacosmia). Sensations of disagreeable taste
are often associated cacogeusia).
11. Taste
Older notions of a “tongue map,” which implied
the existence of specific areas subserving one or
another taste, are incorrect. Any one taste bud is
capable of responding to a number of sapid
substances, but it is always preferentially
sensitive to one type of stimulus.
