martin chapter 9 Flashcards
what are the 2 neural systems that process chemical stimuli?
gustatory and olfactory system
where are the primary cortical areas for taste and smell?
within the limbic system regions
taste is mediated by 3 cranial nerves thanks to their innervation of oral structures
facial (VII)
glossopharyngeal (IX)
vagus (X)
taste receptor cells are clustered in?
taste buds
located on the tongue and at various intraoral sites
name of the chemicals from food that activate taste receptor cells
tastants
depending on the particular chemical they can activate taste cells both by binding on membrane receptors or they can directly pass through membrane channels
taste cells are innervated by?
distal branches of the primary afferent fibers In the facial, glossopharyngeal and vagus nerve
what’s the role of the primary afferent fiber?
to receive infos from particular classes of taste receptor cells and to transmit this sensory info to the CNS (encoded as action potentials)
the central branches of afferent fibers innervating the taste buds, after entering the brain stem, collect in?
the solitary tract of the dorsal medulla and terminate in the rostral portion of the solitary nucleus
where do the axons of the second order neurons in the rostral portion of the solitary nucleus ascend and terminate?
they ascend ipsilaterally in the brain stem in the central tegmental tract and terminate in the parvocellular division of the ventral posterior medial nucleus (in the thalamus)
where do third order neurons in the thalamus project?
they project to
-posterior limb of internal capsule
-the insular cortex and nearby operculum
these are the locations of the primary gustatory cortex
projections of the insular gustatory cortex to the orbitofrontal cortex, the cingulate cortex and other insular areas are important for?
-integration of gustatory information with olfactory informations
-for the behavioral and affective significance of taste
what are taste receptor cells?
epithelial cells that transduce chemical stimuli within the oral cavity into neural signals
taste buds contain 3 cell types
-taste receptor cells
-basal cells (stem cells that differentiate into receptor cells)
-supporting cells (provide structural support)
taste buds on the tongue are clustered on?
papillae
taste receptor cells that are located on the anterior 2/3 of the tongue are innervated by?
chorda tympani nerve, a branch of the facial nerve
the posterior third of the tongue is supplied by?
lingual branches of glossopharyngeal nerve
taste buds in the epiglottis are supplied by?
superior laryngeal nerve, a branch of the vagus nerve
taste buds on the palate are supplied by?
the greater petrosal nerve, a branch of the facial nerve (arises from the intermediate part of the facial nerve)
taste buds on the pharynx are innervated by?
glossopharyngeal nerve
where are the cell bodies of afferent fibers that innervate taste receptor cells located?
in peripheral sensory ganglia
where are the cell bodies of afferent fibers of the intermediate branch of the facial nerve located?
in the geniculate ganglion
where are the cell bodies of the afferent fibers of the vagus and glossopharyngeal nerves located?
in their respective inferior ganglia
where do the afferent fibers of the intermediate branch of the facial nerve enter the brain stem?
at the pontomedullary junction
where do the taste fibers of the glossopharyngeal and vagus nerves enter the brain stem?
in the rostral medulla
