Question 1

Which of the following statements concerning the sensation of smell is correct?&#10;A)Not well developed in humans&#10;B)Does not adapt to continuous stimulation&#10;C)Transmitted in solitary tract of brain stem&#10;D)All of the above are correct

Accepted Answer

The sense of smell, or olfaction, is not as highly developed in humans as it is in many other animals. Humans adapt to smells over time, which is why we can become "nose blind" to continuous odors. The olfactory information is processed in the olfactory bulb and cortex, not in the solitary tract of the brain stem, which is involved in the sensations of taste and visceral sensations.

Question 2

Which of the following best describes the transduction mechanism after activation of an odorant receptor?&#10;A)Cyclic adenosine monophosphate activation of potassium channel&#10;B)Cyclic guanosine activation of sodium channel&#10;C)G-protein activation of adenyl cyclase&#10;D)G-protein activation of guanylyl cyclase

Accepted Answer

After activation of an odorant receptor, the transduction mechanism involves G-protein activation of adenyl cyclase, leading to the production of cyclic adenosine monophosphate (cAMP). This cAMP ultimately opens ion channels, causing a depolarization of the olfactory sensory neuron and initiating an action potential.

Question 3

Which of the following occurs during olfactory signal transduction?&#10;A)Odorant molecule binds to mucous layer covering olfactory cilia, which results in activation of voltage-gated potassium channels&#10;B)Odorant molecule binds directly to an odorant-gated ion channel&#10;C)Odorant molecule binds to receptor, which results in activation of a G protein that induces the formation of cyclic guanosine monophosphate, which opens a sodium channel&#10;D)Odorant molecule binds to receptor, which results in activation of a G protein that induces the formation of cyclic adenosine monophosphate, which opens a sodium channel

Accepted Answer

Odorant molecules bind to receptors on the olfactory cilia, activating a G protein (Golf) that then induces the formation of cyclic adenosine monophosphate (cAMP). The increase in cAMP opens sodium channels, leading to depolarization of the olfactory sensory neuron and initiation of a nerve impulse.

Question 4

The first central synapse for neurons transmitting the sweet taste sensation is in the nucleus of which of the following?&#10;A)Vagus nerve&#10;B)Solitary tract&#10;C)Olfactory nerve&#10;D)Hypoglossal nerve

Accepted Answer

The solitary tract nucleus is the first central synapse for neurons transmitting the sweet taste sensation, as well as the other primary taste sensations. The vagus nerve, olfactory nerve, and hypoglossal nerve are not directly involved in the transmission of taste sensations.

Question 5

Glutamate is thought to be the primary source of stimulation of which of the following taste sensations?&#10;A)Umami&#10;B)Sour&#10;C)Salty&#10;D)Bitter

Accepted Answer

Glutamate is the primary source of stimulation for the taste sensation of umami. Umami is often referred to as the "savory" taste and is found in foods such as meats, cheeses, and mushrooms.

Question 6

Which chemical properties must be at least partially present in a substance for it to be perceived by the olfactory system as an odor?&#10;A)Water soluble&#10;B)Lipid soluble&#10;C)Volatile&#10;D)All of the above

Accepted Answer

For a substance to be perceived as having an odor by the olfactory system, it must be at least partially water soluble, lipid soluble, and volatile. Water solubility allows the substance to dissolve in the mucus of the olfactory epithelium, lipid solubility enables it to interact with the olfactory receptors, and volatility ensures that the substance can enter the nose as a gas.

Question 7

The bitter taste sensation results from stimulation of the appropriate taste receptor by which of the following substances?&#10;A)Long-chain organic substances containing nitrogen&#10;B)Ionized salts&#10;C)Hydrogen ions&#10;D)Complex organic molecules

Accepted Answer

Bitter taste is primarily associated with long-chain organic substances containing nitrogen, which stimulate the appropriate taste receptors.

Question 8

The sour taste sensation results from stimulation of the appropriate taste receptor by which of the following substances?&#10;A)Long-chain organic substances containing nitrogen&#10;B)Ionized salts&#10;C)Hydrogen ions&#10;D)Complex organic molecules

Accepted Answer

The sour taste sensation is primarily caused by the presence of hydrogen ions (H+) in a substance. When hydrogen ions are released from acidic substances, they bind to and stimulate the sour taste receptors on the tongue, resulting in the perception of a sour taste.

Question 9

The rapid adaptation of the taste sensation is thought to be a phenomenon related to which of the following?&#10;A)Taste buds themselves&#10;B)Area from which taste buds are located on the tongue&#10;C)Mechanism in the central nervous system&#10;D)Type of taste sensation

Accepted Answer

Rapid adaptation of taste sensation is a mechanism controlled by the central nervous system. When a taste sensation is prolonged, the neural response to it decreases over time, leading to a reduced perception of the taste. This adaptation helps prevent sensory overload and allows us to detect new tastes more easily.

Question 10

All of the following are considered a primary sensation of smell except:&#10;A)Ethereal&#10;B)Floral&#10;C)Camphoraceous&#10;D)Umami

Accepted Answer

The primary sensations of smell are fruity, floral, spicy, resinous, burnt/chemical, and putrid. Umami is a taste sensation related to the savory flavor of foods and is not related to the sense of smell.

Question 11

The facial nerve is responsible for the innervation of which of the following as it relates to the taste sensation?&#10;A)Posterior portion of the tongue&#10;B)Extraglossal portion of the mouth&#10;C)Anterior portion of the tongue&#10;D)Lateral aspects of the posterior portion of the tongue

Accepted Answer

The answer of The facial nerve is responsible for the...

Question 12

Which of the following types of taste sensation has the greatest sensitivity on a molar basis?&#10;A)Bitter&#10;B)Salty&#10;C)Sour&#10;D)Sweet&#10;E)Umami

Accepted Answer

The answer of Which of the following types of taste...

Question 13

Which of the following substances is most likely to stimulate the umami taste receptors?&#10;A)Complex organic molecules&#10;B)Glutamate&#10;C)Ionized salts&#10;D)Long-chain organic substances containing nitrogen

Accepted Answer

The answer of Which of the following substances is most...

Deck 54: The Chemical Sensestaste and Smell