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Chapter 8. Somatosensory Neurotransmission: Touch, Pain, & Temperature
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A 28-year-old man was seen by a neurologist because he had experienced prolonged episodes of tingling and numbness in his right arm. He underwent a neurologic exam to evaluate his sensory nervous system. Which of the following cutaneous mechanoreceptors is correctly paired with the type of stimulus to which it is most apt to respond?
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A. Pacinian corpuscle and rapid vibration
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B. Meissner corpuscle and skin stretch
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C. Merkel cells and slow vibration
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D. Ruffini corpuscles and sustained pressure
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An MD/PhD student was recording responses in different cutaneous receptors and noted the following. One receptor was inactive until the skin temperature was increased to 33°C and then its firing rate continued to increase as the skin temperature was gradually raised to 45°C. A second receptor was inactive until the skin temperature reached 46°C. A third receptor was inactive at skin temperatures of 40°C, but then steadily increases its firing rate as skin temperature was lowered to 24°C. For each of these cases, classify the type of receptor and the nonselective cation channel that was possibly activated.
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A. Receptor one is a thermal nociceptor and the channel activated was TRPV1; receptor two is a thermal nociceptor and the channel activated was TRPA1; receptor three was an innocuous cold receptor and the channel activated was TRPV4.
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B. Receptor one is an innocuous warm receptor and the channel activated was TRPV1; receptor two is a thermal nociceptor and the channel activated was TRPM8; receptor three was an innocuous cold receptor and the channel activated was TRPV3.
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C. Receptor one is an innocuous warm receptor and the channel activated was TRPV3; receptor two is a thermal nociceptor and the channel activated was TRPV1; receptor three was an innocuous cold receptor and the channel activated was TRPM8.
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D. Receptor one is a thermal nociceptor and the channel activated was TRPA1; receptor two is a thermal nociceptor and the channel activated was TRPV1; receptor three was an innocuous cold receptor and the channel activated was TRPM8.
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List the steps involved in the generation of an action potential in a sensory nerve fiber beginning with the stimulation of a Pacinian corpuscle.
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A. Light touch is applied to the Pacinian corpuscle, and a receptor potential is generated; as the pressure is increased, the size of the receptor potential is increased; when it reaches 30 mV, an action potential is produced at a point of the sensory ...