martin chapter 9

Question 1

what are the 2 neural systems that process chemical stimuli?

Answer 1

gustatory and olfactory system

Question 2

where are the primary cortical areas for taste and smell?

Answer 2

within the limbic system regions

Question 3

taste is mediated by 3 cranial nerves thanks to their innervation of oral structures

Answer 3

facial (VII)
glossopharyngeal (IX)
vagus (X)

Question 4

taste receptor cells are clustered in?

Answer 4

taste buds
located on the tongue and at various intraoral sites

Question 5

name of the chemicals from food that activate taste receptor cells

Answer 5

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

Question 6

taste cells are innervated by?

Answer 6

distal branches of the primary afferent fibers In the facial, glossopharyngeal and vagus nerve

Question 7

what’s the role of the primary afferent fiber?

Answer 7

to receive infos from particular classes of taste receptor cells and to transmit this sensory info to the CNS (encoded as action potentials)

Question 8

the central branches of afferent fibers innervating the taste buds, after entering the brain stem, collect in?

Answer 8

the solitary tract of the dorsal medulla and terminate in the rostral portion of the solitary nucleus

Question 9

where do the axons of the second order neurons in the rostral portion of the solitary nucleus ascend and terminate?

Answer 9

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)

Question 10

where do third order neurons in the thalamus project?

Answer 10

they project to
-posterior limb of internal capsule
-the insular cortex and nearby operculum
these are the locations of the primary gustatory cortex

Question 11

projections of the insular gustatory cortex to the orbitofrontal cortex, the cingulate cortex and other insular areas are important for?

Answer 11

-integration of gustatory information with olfactory informations
-for the behavioral and affective significance of taste

Question 12

what are taste receptor cells?

Answer 12

epithelial cells that transduce chemical stimuli within the oral cavity into neural signals

Question 13

taste buds contain 3 cell types

Answer 13

-taste receptor cells
-basal cells (stem cells that differentiate into receptor cells)
-supporting cells (provide structural support)

Question 14

taste buds on the tongue are clustered on?

Answer 14

papillae

Question 15

taste receptor cells that are located on the anterior 2/3 of the tongue are innervated by?

Answer 15

chorda tympani nerve, a branch of the facial nerve

Question 16

the posterior third of the tongue is supplied by?

Answer 16

lingual branches of glossopharyngeal nerve

Question 17

taste buds in the epiglottis are supplied by?

Answer 17

superior laryngeal nerve, a branch of the vagus nerve

Question 18

taste buds on the palate are supplied by?

Answer 18

the greater petrosal nerve, a branch of the facial nerve (arises from the intermediate part of the facial nerve)

Question 19

taste buds on the pharynx are innervated by?

Answer 19

glossopharyngeal nerve

Question 20

where are the cell bodies of afferent fibers that innervate taste receptor cells located?

Answer 20

in peripheral sensory ganglia

Question 21

where are the cell bodies of afferent fibers of the intermediate branch of the facial nerve located?

Answer 21

in the geniculate ganglion

Question 22

where are the cell bodies of the afferent fibers of the vagus and glossopharyngeal nerves located?

Answer 22

in their respective inferior ganglia

Question 23

where do the afferent fibers of the intermediate branch of the facial nerve enter the brain stem?

Answer 23

at the pontomedullary junction

Question 24

where do the taste fibers of the glossopharyngeal and vagus nerves enter the brain stem?

Answer 24

in the rostral medulla

Question 25

the sense of smell is related by which nerve?

Answer 25

the olfactory nerve

Question 26

where are primary olfactory neurons located?

Answer 26

in the olfactory epithelium

Question 27

structure of primary olfactory neurons

Answer 27

bipolar morphology the peripheral portion is chemosensitive (which contains transmembrane olfactory receptors-a specific one for each neuron that dictates the spectrum of odorants to which the neuron is sensitive) the central portion is an unmyelinayed axon that project to the CNS

Question 28

where is the olfactory epithelium anatomically located?

Answer 28

in the superior nasal concha

Question 29

which is the structure through which olfactory nerve fascicles pass?

Answer 29

they pass through the foramina of the the crib form plate of the ethmoid bone

Question 30

the olfactory nerve is formed by?

Answer 30

the numerous small fascicles formed by the unmyelinated axons of the primary olfactory neurons

Question 31

nerve fascicles of primary olfactory neurons that passed through the crib form plate synapse where? and with what?

Answer 31

synapse with second order olfactory neurons in the olfactory bulb

Question 32

what is the basic odorant processing unit of the olfactory bulb?

Answer 32

the glomerulus the axons of primary olfactory neurons that carry the same olfactory receptor are collected within the same glomerulus

Question 33

name of the tract through which second order olfactory neurons project to the olfactory cortex

Answer 33

olfactory tract

Question 34

the olfactory cortex is part of?

Answer 34

the primitive allocortex (fewer layers than the neocortex)

Question 35

the olfactory cortex is made by 5 separate areas (5 primary areas) that receive a direct projection from the olfactory bulb:

Answer 35

1. anterior olfactory nucleus 2. amygdala 3. olfactory tubercle 4. piriform cortex 5. rostral entorhinal cortex

Question 36

the medial dorsal nucleus of the thalamus receive olfactory informations from?

Answer 36

the primary areas

Question 37

in addition to the olfactory neurons, the olfactory epithelium contains 2 other cell types

Answer 37

1. supporting cells 2. basal cells (stem cells that differentiate into primary olfactory neurons as the mature sensory neurons die)

Question 38

vomeronasal organ

Answer 38

-another component of the olfactory system -comprises a portion of the olfactory epithelium separate from the main olfactory epithelium -neurons of the vomeronasal organ project to the accessory olfactory bulb which projects only to the amygdala -there is no evidence that is a functioning olfactory sensory organ

Question 39

the olfactory bulb is the recipient for ?

Answer 39

migrating neurons that are born in maturity within specialized regions of the wall of the lateral ventricle. these neurons migrate along the ventricular wall into the bulb where they are involved in local olfactory circuits

Question 40

olfactory receptor cells synapse on 3 types of neurons in the olfactory bulb:

Answer 40

mitral cells and tufted cells (the two projection neurons of the olfactory bulb) periglomerural cells (interneurons)

Question 41

the glomerulus is made of?

Answer 41

axon terminals of olfactory receptor cells and the dendrites of mitral, tufted and periglomerural cells

Question 42

names of the 2 inhibitory interneurons in the olfactory bulb

Answer 42

granule cell periglomerural cell

Question 43

where do the olfactory bulb and tract lie?

Answer 43

in the olfactory sulcus on the ventral surface of the frontal lobe

Question 44

as the olfactory tract approaches to the region in which it fuses with the cerebral hemispheres, it bifurcates into?

Answer 44

lateral olfactory stria (which contains the axons from the olfactory bulb) medial olfactory stria (contains the axon from other brain regions that are projecting to the olfactory bulb)

Question 45

where do tiny branches of the anterior cerebral artery perforate the ventral brain surface?

Answer 45

in the anterior perforated substance, which is grey matter

Question 46

there are 2 major kinds of allocortex

Answer 46

archicortex (located primarily in the hippocampal formation) paleocortex (located on the basal surface of cerebral hemispheres, in part of the insular cortex and caudally along the parahippocampal gyrus and retrosplenial cortex)

Question 47

the amygdala has 3 major nuclear divisions

Answer 47

corticomedial nuclear group basolateral nuclear group the central nucleus

Question 48

to which portion of the amygdala does the olfactory bulb project?

Answer 48

to a portion of the corticomedial nuclear group

Question 49

where is the olfactory tubercle located?

Answer 49

It is part of the basal forebrain and is medial to the olfactory tract. Neurons in the olfactory tubercle receive inputs from and project their axons to brain regions that play a role in emotions