Question 1

Which of the following statements best describes the specificity of olfactory receptors in humans?

Accepted Answer

Each olfactory receptor cell expresses only one type of receptor protein, but each receptor can bind multiple odorants.

Question 2

A patient presents with a loss of smell following a head injury. Which structure is most likely damaged, resulting in anosmia?

Accepted Answer

Filaments of the olfactory nerve (cranial nerve I)

Question 3

Which cranial nerve is primarily responsible for transmitting taste sensations from the anterior two-thirds of the tongue?

Accepted Answer

Facial nerve (VII)

Question 4

Which of the following best explains why foods taste bland when you have a blocked nose?

Accepted Answer

Olfactory input contributes approximately 80% to the perception of taste.

Question 5

Which of the following is the correct sequence of events in olfactory transduction?

Accepted Answer

Odorant binds receptor → G protein activates adenylate cyclase → cAMP opens cation channels → Na$$^+$$ and Ca$$^{2+}$$ influx → depolarization

Question 6

Which taste sensation is most sensitive and serves as a protective mechanism against potentially harmful substances?

Accepted Answer

Bitter

Question 7

A mutation in the gene encoding the G protein gustducin would most directly affect the transduction of which taste sensations?

Accepted Answer

Sweet, bitter, and umami

Question 8

Which of the following best describes the role of mitral cells in the olfactory pathway?

Accepted Answer

They are second-order neurons that amplify, refine, and relay olfactory signals to the brain.

Question 9

Which of the following equations correctly represents the conversion catalyzed by adenylate cyclase during olfactory transduction?

Accepted Answer

$$\mathrm{ATP} \rightarrow \mathrm{cAMP} + \mathrm{PP_i}$$

Question 10

Which of the following best explains why dogs have a superior sense of smell compared to humans?

Accepted Answer

Dogs have a larger olfactory bulb relative to brain size and more olfactory receptor neurons.

Question 11

Which of the following cranial nerves is NOT involved in transmitting gustatory signals from the tongue to the brain?

Accepted Answer

Trigeminal nerve (V)

Question 12

Which of the following is TRUE regarding the regeneration of olfactory neurons?

Accepted Answer

Olfactory neurons are replaced every 30–60 days by stem cells at the base of the epithelium.

Question 13

Which of the following best describes the process by which salty taste is detected?

Accepted Answer

Na$$^+$$ influx directly depolarizes the gustatory epithelial cell.

Question 14

A patient with temporal lobe epilepsy reports experiencing olfactory hallucinations (phantosmia) before a seizure. Which brain region is most likely involved?

Accepted Answer

Olfactory cortex

Question 15

Which of the following is NOT a requirement for a chemical to be detected as an odorant?

Accepted Answer

It must be an inorganic salt.

Question 16

Which of the following best describes the pathway of gustatory signals from the tongue to the cortex?

Accepted Answer

Taste bud → cranial nerve → solitary nucleus (medulla) → thalamus → gustatory cortex (insula)

Question 17

Which of the following best explains why spicy foods can be perceived as pleasurable by some individuals?

Accepted Answer

Spicy foods excite pain receptors (nociceptors) in the mouth, which can be interpreted as pleasurable.

Question 18

Which of the following is TRUE regarding the adaptation of taste receptors?

Accepted Answer

Taste receptors adapt rapidly, with complete adaptation in 1–5 minutes.

Question 19

Which of the following best describes the function of the glomeruli in the olfactory bulb?

Accepted Answer

They are regions where axons from neurons with the same receptor type converge and synapse with mitral cells.

The Chemical Senses: Smell (Olfaction) and Taste (Gustation)

Study Guide - Practice Questions

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