TEST BANK For Ganong’s Review of
Medical Physiology (23rd edition) by Kim
Barrett, Heddwen Brooks, Scott Boitano and
Susan Barman.
National Board–Style MCQs with 100%
Correct Answers and Explanations
Volume III – Chapter 14-26.
,Chapter 14 – Smell & Taste
1. The sensory receptors for smell are located in the:
A. Inferior turbinate
B. Olfactory bulb
C. Olfactory epithelium of upper nasal cavity
D. Nasopharynx
E. Maxillary sinus
✅ Answer: C
Explanation:
Olfactory receptors are found in the olfactory epithelium over the superior nasal septum and
superior turbinate.
2. Olfactory receptor neurons are unique because they:
A. Are bipolar neurons
B. Are replaced throughout life
C. Use Na⁺ channels for transduction
D. Synapse in the thalamus first
E. Are myelinated
✅ Answer: B
Explanation:
Olfactory receptor neurons undergo continuous regeneration from basal stem cells.
3. Odorant binding to receptors results in activation of:
A. IP₃ pathway
B. Tyrosine kinase
C. cAMP pathway
D. Ca²⁺-ATPase
E. Phospholipase C exclusively
✅ Answer: C
Explanation:
Odorants activate Gs → adenylate cyclase → ↑ cAMP, opening cation channels.
,4. Depolarization of olfactory receptor neurons is mainly due to influx of:
A. Na⁺ only
B. Ca²⁺ only
C. Cl⁻ efflux
D. K⁺ influx
E. H⁺ influx
✅ Answer: C
Explanation:
Ca²⁺ influx opens Ca²⁺-activated Cl⁻ channels, and Cl⁻ efflux causes depolarization.
5. Each olfactory receptor neuron expresses:
A. All odorant receptors
B. Two odorant receptors
C. One type of odorant receptor
D. No specific receptor
E. Taste receptors
✅ Answer: C
Explanation:
Each olfactory neuron expresses only one odorant receptor gene, allowing precise odor coding.
6. Olfactory receptor neurons synapse in the:
A. Thalamus
B. Hypothalamus
C. Piriform cortex
D. Olfactory bulb
E. Amygdala
✅ Answer: D
Explanation:
Primary synapse occurs in the olfactory bulb, forming glomeruli.
, 7. Which cranial nerve carries olfactory sensation?
A. CN V
B. CN VII
C. CN IX
D. CN X
E. CN I
✅ Answer: E
Explanation:
Smell is mediated by olfactory nerve (CN I).
8. Olfactory pathway is unique because it:
A. Uses GABA
B. Is bilateral
C. Does not relay in thalamus before cortex
D. Has only one synapse
E. Uses glutamate only
✅ Answer: C
Explanation:
Olfaction is the only sensory system that bypasses the thalamus initially.
9. Taste buds are primarily located on the:
A. Hard palate
B. Soft palate
C. Filiform papillae
D. Fungiform, circumvallate, and foliate papillae
E. Esophagus
✅ Answer: D
Explanation:
Taste buds are present in fungiform, circumvallate, and foliate papillae (not filiform).
Medical Physiology (23rd edition) by Kim
Barrett, Heddwen Brooks, Scott Boitano and
Susan Barman.
National Board–Style MCQs with 100%
Correct Answers and Explanations
Volume III – Chapter 14-26.
,Chapter 14 – Smell & Taste
1. The sensory receptors for smell are located in the:
A. Inferior turbinate
B. Olfactory bulb
C. Olfactory epithelium of upper nasal cavity
D. Nasopharynx
E. Maxillary sinus
✅ Answer: C
Explanation:
Olfactory receptors are found in the olfactory epithelium over the superior nasal septum and
superior turbinate.
2. Olfactory receptor neurons are unique because they:
A. Are bipolar neurons
B. Are replaced throughout life
C. Use Na⁺ channels for transduction
D. Synapse in the thalamus first
E. Are myelinated
✅ Answer: B
Explanation:
Olfactory receptor neurons undergo continuous regeneration from basal stem cells.
3. Odorant binding to receptors results in activation of:
A. IP₃ pathway
B. Tyrosine kinase
C. cAMP pathway
D. Ca²⁺-ATPase
E. Phospholipase C exclusively
✅ Answer: C
Explanation:
Odorants activate Gs → adenylate cyclase → ↑ cAMP, opening cation channels.
,4. Depolarization of olfactory receptor neurons is mainly due to influx of:
A. Na⁺ only
B. Ca²⁺ only
C. Cl⁻ efflux
D. K⁺ influx
E. H⁺ influx
✅ Answer: C
Explanation:
Ca²⁺ influx opens Ca²⁺-activated Cl⁻ channels, and Cl⁻ efflux causes depolarization.
5. Each olfactory receptor neuron expresses:
A. All odorant receptors
B. Two odorant receptors
C. One type of odorant receptor
D. No specific receptor
E. Taste receptors
✅ Answer: C
Explanation:
Each olfactory neuron expresses only one odorant receptor gene, allowing precise odor coding.
6. Olfactory receptor neurons synapse in the:
A. Thalamus
B. Hypothalamus
C. Piriform cortex
D. Olfactory bulb
E. Amygdala
✅ Answer: D
Explanation:
Primary synapse occurs in the olfactory bulb, forming glomeruli.
, 7. Which cranial nerve carries olfactory sensation?
A. CN V
B. CN VII
C. CN IX
D. CN X
E. CN I
✅ Answer: E
Explanation:
Smell is mediated by olfactory nerve (CN I).
8. Olfactory pathway is unique because it:
A. Uses GABA
B. Is bilateral
C. Does not relay in thalamus before cortex
D. Has only one synapse
E. Uses glutamate only
✅ Answer: C
Explanation:
Olfaction is the only sensory system that bypasses the thalamus initially.
9. Taste buds are primarily located on the:
A. Hard palate
B. Soft palate
C. Filiform papillae
D. Fungiform, circumvallate, and foliate papillae
E. Esophagus
✅ Answer: D
Explanation:
Taste buds are present in fungiform, circumvallate, and foliate papillae (not filiform).
