NB2 Lecture 3+4; DLA 30 + 31

Question 1

gustatory pathway

Answer 1

1. anterior tongue (CN VII) / posterior tongue (CN IX) / epiglottis (CN X)
2. solitary nucleus (medulla)
3. ventro-postero-medial nucleus (thalamus)
4. primary gustatory cortex (insula / frontal operculum in cortex)

this pathway remains ipsilateral

Question 2

CN 1

Answer 2

sense of smell

Peripheral processes and cell bodies located in the olfactory epithelium of the nasal cavity

Fibers pass through the cribriform plate to the olfactory bulb

Fibers pass through the olfactory tracts and terminate in the cortex

Question 3

anosmia

Answer 3

Loss of smell

Question 4

Kiesselbach’s area

Answer 4

This area is the most common site of significant nosebleeds

lots of vasculature

Question 5

nerves of the lateral nasal wall

Answer 5

branches of the ophthalmic division (CN
V1) and the maxillary division (CN V2 of the
trigeminal n.)

Question 6

nerves of the nasal septum

Answer 6

Anterosuperior part of the septum is supplied by
branches of the ophthalmic division (CN V1)

Rest by branches of the maxillary division (CN V2)

Question 7

Olfactory signal transduction

Answer 7

Metabotropic signal transduction

The second messenger is cAMP

Question 8

gustatory ionotropic transduction

Answer 8

salty (Na)
sour (H+)

taste ion… current through ion channel…..depolarization…..transmitter release

Question 9

gustatory metabotropic transduction

Answer 9

Sweet (cAMP)
bitter (IP3)

Taste molecule → Receptor binding → G-protein → Enzyme → Second messenger → Current through ion channel → Depolarization → Transmitter release

Question 10

primary, secondary, and tertiary gustatory neurons

Answer 10

primary: axon in peripheral nerve; cell body in
peripheral ganglion

secondary: Cell body in CNS; synapse in thalamus (no crossing over)

tertiary: : cell body in thalamus; axon through
internal capsule and corona radiata; synaptic terminal in primary gustatory cortex

Question 11

Hyposmia

Answer 11

decreased ability to smell

Question 12

Hypogeusea

Answer 12

decreased ability to taste

Question 13

Ageusea

Answer 13

no ability to taste

Question 14

Olfactory Hallucinations

Answer 14

A patient suffering from epileptic seizures originating in the vicinity of the uncus may sometimes experience olfactory hallucinations

like the experience of a pungent, unpleasant smell, in the absence of odorants that would explain such smell sensations

Question 15

Suprahyoid muscles

Answer 15

Open the mouth

Elevate hyoid bone and move it forward during
swallowing

Question 16

Mylohyoid nerve

Answer 16

innervate mylohyoid

anterior belly of digastric

Question 17

stylohyoid m

Answer 17

facial nerve

posterior digastric

Question 18

geniohyoid m

Answer 18

Ventral ramus of spinal nerve C1 (traveling with

hypoglossal nerve

Question 19

nerves that allow for taste

Answer 19

vagus
glossopharyngeal
facial

Question 20

touch pain temp of tongue innervation

Answer 20

vagus
glossopharyngeal
lingual

Question 21

Palatoglossus

Answer 21

elevates tongue

CN X

Question 22

Genioglossus

Answer 22

protrudes tongue

CN XII

Question 23

Hyoglossus

Answer 23

depresses tongue

CN XII

Question 24

Styloglossus

Answer 24

retracts tongue

CN XII

Question 25

intrinsic muscles of tongue

Answer 25

change shape of tongue

superior longitudinal
inferior longitudinal
transverse
vertical