Term
| What is the difference between different muscle fibers? |
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Definition
- Skeletal - control muscle tone, notifies cord of change in length
- Extrafusal - contraction of skeletal muscle
- Intrafusal - detects change in muscle length |
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Term
| What is the difference between motor neurons and sensory afferents? |
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Definition
- I and II sensory afferents - response to rate and degree of stretch
- Alpha motor neurons - largest, innervate extrafusal
- Gamma motor neurons - innervate intrafusal -- spindle sensitivity |
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Term
| What is the difference between a sprain and a strain? |
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Definition
- Sprain - stretch or tear of a LIGAMENT
- Strain - twist, pull, or tear of a tendon or muscle |
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Term
| What is the stretch reflex? |
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Definition
Monosynaptic - no interneuron
A muscle stretches, sends an impulse to type I sensory neurons --> direct synapse w/ alpha motor neurons in the dorsal horn, which goes back to muscle --> stretched muscle contracts, opposing the stretch.
- Patellar/knee jerk reflex |
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Term
| What is the flexor relex? |
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Definition
A polysynaptic reflex, involves interneurons
Polysynaptic reflexes can have multiple spasms - different motor pathways |
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Term
| Where are sensory and motor impulses modulated? |
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Definition
- Sensory - dorsal horn
- Motor - ventral horn |
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Term
| How does neuropathic pain evolve? |
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Definition
Damage to nerves within a degenerated disc, compacted bone, or a herniated disc
Usually due to age, injury, or OA |
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Term
| What are the two classifications of skeletal muscle relaxants? |
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Definition
- Antispasmotic agent - treats back pain, sciatica, etc, caused by injury. Do not directly affect skeletal muscle - effects in the spinal cord
- Antispasticity agent - treats upper motor neuron disorders such as MS or cerebral palsy - DIRECTLY interfere w/ calcium release from SR. |
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Term
Which agents are Antispasmotic agents?
Polysynaptic neuronal inhibitors. |
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Definition
- Flexeril/cyclobenzaprine - blocks 5-HT2
- Soma/Carisoprodol - metabolite meprobamate has abuse potential
- Robaxin/Methocarbamol - inhibits activity of ACHase agest - myasthenia gravis
- Skelaxin/Metaxolone
- Paraflex or Parafon forte/Chlorzoxazone - red or orange urine
- Norflex/Orphenadrine - related to benadryl, also blocks NMDA |
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Term
Which agents are antispasticity agents?
Which agents are mixed? |
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Definition
- Lioresal or Kemstro/Baclofen - GABAb agonist (GPCR) -- hyperpolarization. Also inhibits Sub P. Inhibits mono- and polysynaptic reflexes
- Dantrium/Dantrolene - ONLY direct skeletal muscle relaxant. Block RyR calcium receptor - malignant hypothermia. No calcium efflux.
MIXED:
- Valium/Diazepam - a BZD that binds to GABAa, increases frequency of opening
- Zanaflex/Tizanidine - alpha2 agonist interferes with polysynaptic reflexes. Decrease in excitation in ventral horn. |
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Term
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Definition
Similar to TCAs, but not it's MoA. Does not act on NMJ
Interferes with descending alpha motor neuron - Blocks polysynaptic reflex. What all other antispasmotic agents do. Ventral horn of the spinal cord!
ALSO: blocks 5-HT2 receptors, decreasing contraction. |
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Term
| What are the side effects of Flexeril? |
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Definition
- CNS depression
- Anticholinergic: sedation, constipation, dry mouth |
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