Olfactory/Gustatory Anatomy

Question 1

Where does olfactory bulb lie?

Answer 1

• On cribiform plate
• Inferior to medial aspect of frontal lobe
• Rostral end of anterior cranial fossa

Question 2

Where are odor receptors found?

Answer 2

• In olfactory mucosa @ roof of nasal cavity (inf. surface of cribiform plate)
• Along nasal septum and medial wall of sup. turbinate

Question 3

Pathway of olfactory receptor neurons?

Answer 3

Pass through lamina propria - group into olfactory fila - make up CN I - pass through cribiform plate - terminate in olfactory bulb

Question 4

Process of olfactory perception

Answer 4

Odor molecules inhaled - contact mucus layer - OMs bind odorant receptors - GPCR pathway - depolarization - AP

Question 5

Role of periglomerular cells?

Answer 5

They branch extensively in glomerulus and send axons to surrounding glomeruli (crosstalk)

Question 6

What makes up the external plexiform layer?

Answer 6

• Tufted cells and dendrites of tufted cells, mitral cells and granule cells

Question 7

What’s special about granular cells?

Answer 7

No axons (dendrodendritic)

Question 8

What area is known as the olfactory cortex?

Answer 8

Ventral surface of telencephalon

Question 9

Main targets of anterior olfactory nucleus

Answer 9

Olfactory bulbs bilaterally and to the CL anterior olfactory nucleus

Question 10

Where is olfactory info projected to?

Answer 10

• Insular and orbitofrontal cortices and the dorsomedial nucleus (thalamus) (which produce experience of flavors)

Question 11

Where is olfactory info directed to?

Answer 11

Lateral hypothalamus and hippocampus

Question 12

How does taste transduction occur?

Answer 12

Soluble chemicals diffuse through taste pore and bind receptors on apical microvilli of taste cells
- Significant depolarization - AP - relayed to afferent fibers - 1st order neurons

Question 13

What does the chorda tympani (CN VII) innervate?

Answer 13

• Fungiform papillae on ant. 2/3 of tongue

- Anterior foliate papillae

Question 14

What does the greater petrosal n. (CN IX) innervate?

Answer 14

Taste buds on soft palate

Question 15

Where are cell bodies for CN VII located?

Answer 15

Geniculate ganglion

Question 16

What does the lingual-tonsillar branch (CN IX) innervate?

Answer 16

• Taste buds in vallate papillae

- Posterior foliate papillae

Question 17

What does sup. laryngeal n. innervate?

Answer 17

Taste buds of epiglottis and esophagus

Question 18

Where do fibers from CN IX and X have cell bodies?

Answer 18

Inferior ganglia (petrosal and nodose)

Question 19

Effect of CN VII lesion?

Answer 19

• IL loss of taste from anterior 2/3 of tongue (chorda tympani leaving CN VII distal to geniculate gang.)
• IL facial paralysis, hyperacusis (stapedius m. paralyzed)
• IL impaired secretion from glands

Question 20

Effect of damage distal to geniculate ganglion?

Answer 20

• Taste loss may or may not happen

- IL facial paralysis