Term
| Which system includes the cuneatus and gracilis tracts? |
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Definition
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Term
| What sensations do the cuneatus and gracilis tracts carry? |
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Definition
| Touch, pressure, and vibration |
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Term
| Which type of monitoring assesses the integrity of cuneatus/gracilis tracts? |
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Definition
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Term
| Do the cuneatus and gracilis tracts cross over? If so, where? |
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Definition
| They cross at the brain stem |
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Term
| What system is responsible for the alert/awake state? |
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Definition
| RAS (reticular activating system) |
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Term
| What nerve is usually monitored for SSEP? Where is the electrode placed? |
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Definition
| The tibial nerve; the electrode is placed midline scalp |
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Term
| What nerves can be used for SSEPs besides the tibial? Where are the electrodes? |
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Definition
| Ulnar and radial; the electrode is placed on the lateral scalp |
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Term
| Where are motor evoked potentials stimulated and monitored? |
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Definition
| MEPs usually involve the popliteal nerve; stimulation is done over the motor cortex with sensing at the popliteal nerve |
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Term
| Which cranial nerve do brainstem auditory evoked potentials (BAEP's) monitor? |
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Definition
| CN VIII (vestibulocochlear) |
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Term
| Which cranial nerve does visual evoked potentials (VEPs) monitor? |
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Definition
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Term
| List the EP's in order of most anesthetic-sensitive to least |
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Definition
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Term
| Where are the cell bodies of the A-delta and C fiber afferents found? |
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Definition
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Term
| Which tract is responsible for pain afferents? |
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Definition
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Term
| Do pain afferents cross the cord? If so, when? |
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Definition
| Yes, they immediately cross |
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Term
| Where do the axons of the A-delta fibers (carrying sharp pain and temp) terminate? What happens from there? |
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Definition
| The axons of the A-delta fibers terminate in Rexed's lamina I and V; from there, the 2nd order neuron crosses over to the contralateral anterolateral system and ascends to the brain |
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Term
| Where do the axons of the slow-pain C fibers terminate? What happens from there? |
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Definition
| The C fibers terminate in Rexed's laminae II/III. From there, interneurons transmit from II/III to laminae V; neurons leaving laminae V cross immediately to the contralateral anterolateral system, where they ascend |
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Term
| What is the major neurotransmitter released from A-delta fibers? Which receptors does it bind to post-synaptically? |
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Definition
| Glutamate is the major A-delta transmitter; it binds to AMPA receptors |
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Term
| What is the major neurotransmitter released from slow C fibers? What receptor does it bind to post-synaptically? |
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Definition
| Substance P is the major C-fiber neurotransmitter; it binds to NK-1 receptors |
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Term
| What is the purpose of the lateral spinothalamic tract? Dorsolateral fasciculus tract? |
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Definition
| The lateral spinothalamic carries pain and temperature up to the brain; the dorsolateral funiculus is a descending tract that modulates pain |
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Term
| What transmitter do interneurons in the slow pain pathway release? What does this transmitter do? |
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Definition
| Interneurons have receptors that respond to Substance P released from the C-fiber terminal. These interneurons then release enkephalin, which binds to Mu-2 receptors on the C-fiber terminal. Binding to the Mu-2 receptors reduces the release of substance P, which in turn decreases the nerve impulses transmitted through the pain pathway |
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Term
| Describe how pain is modulated via the descending tracts. |
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Definition
| Impulses that arise in the periventricular/periaqueductal gray matter descend down an interneuron to the nucleus raphe magnus; it is then transmitted down the descending dorsolateral funiculus; at its end, it causes release of enkephalin; enkephalin binds to Mu-2 receptors on the pre-synaptic afferent C-fiber; this causes a decrease in Substance P release and hence less impulse transmission up the ascending lateral spinothalamic tract |
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Term
| What effects are attributed to Mu-1 |
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Definition
| Supraspinal analgesia, decreased heart rate, euphoria, and itching |
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Term
| What effects are attributed to Mu-2 receptors? |
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Definition
| Spinal analgesia, respiratory depression, and addiction |
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