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13 Cards in this Set
- Front
- Back
Stimulus transduction?
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The process of converting stimulus energy to electrical energy
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What causes a depolarizing receptor potential?
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Influx of Na and Ca
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How is stimulus intensity conveyed neurologically?
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The intensity of a stimulus is encoded in the frequency of action potential firing (Frequency Code) and by the number of neurons that are activated (Population Code).
Note: This is DIFFERENT than being encoded in the amplitude of the axonal action potential arriving in the dorsal horn. Frequency! Not Amplitude! |
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Tonic vs. Phasic receptors
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Tonic - Receptors that slowly adapt or remain persistently activated during an applied stimulus
Phasic - Rapidly adapting receptors that fire APs only when the stimulus is changing such as during the applicatin and/or cessation of a stimulus |
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Is a Pacinian corpuscle tonic or phasic?
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Phasic because the firing of Pacinian Corpuscles stops when the stimulus comes to rest
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Does tonic or phasic convey information about the duration of the stimulus?
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Tonic
Phasic stimuli are better at sensing onset and ending of the stimuli |
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Slow vs Fast adaptation?
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Adaptation is a process in which the sensitivity of a receptor and AP firing rate gradually decrease despite continued stimulation
Slow = Tonic receptors Fast = Phasic receptors |
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Characteristics of Merkel Disc Receptors
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Slow adapting; small receptor field
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Characteristics of Meissner Corpuscle Receptor
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Rapid adapting; small receptor field
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Characteristics of Pacinian Corpuscle
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Rapid adapting; Large receptor field
- Note: good at sensing vibration |
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Characteristics of Ruffini Endings
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Slow adapting, Large receptor area
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What is a nociceptor and is it slow or rapid type?
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They are free nerve endings widely dispersed in the skin. They are sensitive to painful stimuli.
They are slow adapting so that pain persists as long as the noxious stimulus persists |
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What are A fibers and C fibers in the nociceptive pathway?
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A fibers are the fast myelinated "ouch" receptor.
C fibers are the slow unmyelinated dull pain receptor |