Quiz 7: The Somatosensory System

Fast-adapting type 1 fibers respond to a tactile stimulus by a: A)Maintained increase in firing rate for the duration of the stimulus B)Maintained decrease in firing rate for the duration of the stimulus C)Transient increase in firing rate at the initiation and cessation of the stimulus D)Transient increase in firing rate at the initiation of the stimulus and a transient decrease in firing rate at its cessation E)Transient decrease in firing rate at the initiation of the stimulus and a transient increase in firing rate at its cessation

Pacinian corpuscles are located: A)Superficially in the dermis and thus have receptive fields with sharp borders B)Deep in the dermis and thus have receptive fields with sharp borders C)Superficially in the dermis and thus have receptive fields with poorly defined borders D)Deep in the dermis and thus have receptive fields with poorly defined borders

The main pathway for fine discriminative touch information from the hand to the cerebral cortex includes: A)Group A-β axons  fasciculus cuneatus  medial lemniscus  ventroposterolateral (VPL)nucleus  postcentral gyrus B)Group C axons  fasciculus cuneatus  medial lemniscus  VPL nucleus  postcentral gyrus C)Group A-β axons  fasciculus cuneatus  medial lemniscus  VPL nucleus  precentral gyrus D)Group C axons  fasciculus cuneatus  medial lemniscus  VPL nucleus  precentral gyrus E)Group A- axons  fasciculus gracilis  medial lemniscus  VPL nucleus  postcentral gyrus

Which of the following sequences represents a pathway for conscious proprioceptive information (kinesthesia)from the lower limb? A)Dorsal root ganglion cells  nucleus dorsalis  dorsal spinocerebellar tract  superior cerebellar peduncle B)Clarke's column  ventral spinocerebellar tract  inferior cerebellar peduncle C)Dorsal root ganglion cells  dorsal spinocerebellar tract  nucleus z  medial lemniscus  VPL nucleus D)Fasciculus cuneatus  internal arcuate fibers  medial lemniscus  VPL nucleus

In the primary somatosensory cortex (SI): A)All body parts are represented by equal amounts of cortex. B)Body parts are represented by an amount of cortex proportional to their surface area. C)The sensory homunculus has an upright position. D)Proprioceptive and tactile information are directed to different parts of SI cortex and are examples of the labeled-line principle.

Pain fibers: A)Are not activated by a mechanical stimulus unless it is painful B)End in encapsulated receptors C)Are large-caliber myelinated axons D)May be activated by multiple classes of stimuli

A lesion of the dorsal columns would result in: A)Loss of pain sensation B)Impaired graphesthesia C)Loss of ability to localize a tactile stimulus D)Motor weakness

Second pain is mediated by: A)C fibers and is a sharp,highly localized sensation B)C fibers and is a dull,poorly localized sensation C)A- fibers and is a sharp,highly localized sensation D)A- fibers and is a dull,poorly localized sensation

The gate control theory of pain is best described by which of the following statements? A)Transient receptor potential (TRP)channels are gated by temperature. B)Activation of low-threshold mechanoreceptors can reduce or block the activity of ascending pain pathways. C)Gamma aminobutyric acid (GABA)inhibits neurons in the spinal cord. D)After sensitization,a pain fiber begins responding to nondamaging tactile stimuli.

Which nonopioid neurotransmitter is involved in control of pain pathways? A)Serotonin B)Enkephalin C)Dynorphin D)-Endorphin