Exam 4: Gustatory pathways (CN 7, 9, 10)- Michaels

Question 1

What are the three chemosensory systems

Answer 1

Olfaction, gustation, chemesthesis (trigeminal)

Question 2

What do taste buds in the gut do physiologically?

Answer 2

activate molecular pathways that help guide the digestion or rejection of food

Question 3

Describe the innervation of the tongue (taste and touch/temp)

Answer 3

Anterior 2/3rd: Facial= taste, trigeminal= touch and temp, Posterior 1/3rd is supplied by glossopharyngeal

Question 4

Where are the primary afferent nerves (VII, IX, and X) that innervate tastebuds of the head?

Answer 4

7: anterior 2/3 of tongue (via chorda tympani), 9: posterior 1/3rd of tongue, 10: epiglottis and larynx

Question 5

What tract does taste from the mouth/larynx travel to the brainstem? Where do they end?

Answer 5

Solitary tract, end if the nucleus of the solitary tract

Question 6

Where does the solitary nucleus project to?

Answer 6

The reticular formation (Swallowing, coughing, etc.), The hypothalamus and amygdala, the thalamus (medial portion (oral) of the VPM)

Question 7

Where does the portion of the VPM responsible for taste project to?

Answer 7

Gustatory cortex (insula)

Question 8

In what structure do second order neurons from the solitary tract ascend to the taste region of the VPM? Unilateral or bilateral?

Answer 8

Via taste lemniscus, ascend bilaterally

Question 9

What order neurons project from the thalamus to the insular cortex for taste?

Answer 9

Third order neurons

Question 10

where are we consciously aware of taste?

Answer 10

insular cortex

Question 11

What additional information arrives to the orbitofrontal cortex with taste?

Answer 11

Olfactory information to produce the “flavor” sensation

Question 12

What reflexes is the nucleus of the solitary tract also connected to? What nuclei are they?

Answer 12

swallowing (nucleus ambiguus, hypoglossal nucleus), salivation (sup and inf salivatory nuclei), and gagging (nucleus ambiguus)

Question 13

What nerve is used to send information from the chemical monitory system inside our body?

Answer 13

Vagus nerve (and some of 9)

Question 14

What visceral reflexes does the nucleus of the solitary tract participate in?

Answer 14

heart rate and digestion via the dorsal motor nucleus of CN X

Question 15

Where are pattern generators of chewing and swallowing located?

Answer 15

Reticular formation