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54 Cards in this Set
- Front
- Back
What is controlled by the gamma motor neuron?
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The muscle spindle
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What is the fusimotor system?
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The muscle spindle and the associated gamma motor neuron
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What is the function of the gamma motor neuron?
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To give proprioceptive feedback
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In a reflex, which muscle is stimulated and which is inhibited?
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The extensor is stimulated while simultaneously the flexor is inhibited.
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What NT is used to inhibit a skeletal muscle movement in a reflex?
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GABA
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What interneuron of the CNS controls excitability of motor neurons?
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Renshaw cells
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What NT is used by Renshaw cells?
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glycine
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What drug can be used to block glycinergic synpases of the Renshaw cell?
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Strychine
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Why does strychine cause spastic paralysis and convulsions?
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Blocks the regulatory effects of Renshaw cells, allowing uncontrolled excitability (tetanus) of motor neurons.
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How does strychine cause death?
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Spastic paralysis of respiratory muscles
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What is a motor unit?
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Alpha motor neuron with all of the muscle fibers it innervates
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Where are the t-tubules located in the sarcomere?
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in plane with the Z disk
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What depolarizes the T-tubule membrane?
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Action potential propagated through Na channels
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What causes hydropyridine receptors to change the conformation of the ryanodine receptors?
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Depolarization
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What does Ca bind once in the muscle?
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Troponin: allowing binding sites for myosin on actin.
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How is ACh loaded into vesicles?
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Using a vesicle transporter
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What drug is able to block nicotinic ACh receptors?
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Curare
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What drug is able to block muscarinic ACh receptors?
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Atropine
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What type of ions are able to pass through a nicotinic ACh receptor?
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Na/K
It is a non-selection cation channel |
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What type of channel is the nicotinic ACh receptor?
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Ionotropic ligand-gated non-selective ion channel
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What causes vesicle mobilization in the axon terminal?
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Calcium entry from depolarized voltage-gated calcium channels
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What NT is released into the NMJ?
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ACh
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What receptors are present on the motor end plate?
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nicotinic ACh receptors
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What generates the endplate potential?
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Activation of the nicotinic receptors
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What initiates an action potential in the sarcolemma?
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EPP
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What breaks down the ACh after EPP has been produced?
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Actylcholine esterase
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How is choline retrieved?
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Na/Choline transporter
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What carries the action potential throughout the muscle tissue?
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T-tubules
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How is the ryanodine receptor activated?
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Calcium-induced-calcium-release
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What moves the tropomyosin to uncover myosin binding sites on actin?
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Calcium binding to troponin forces a conformational change that moves tropomyosin.
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What toxins effect SNARE proteins and vesicle fusion?
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Botulinum and tetanus toxin
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What is Lambert-Eaton myasthenic syndrome?
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Autoimmune disorder that leads to a loss of voltage-gated presynaptic Ca channels
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Why are the amplitudes of MEPPs unaffected in myasthenic syndrome?
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MEPPs are not calcium dependent.
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What is myasthenia gravis?
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Autoimmune disorder characterized by the antibodies blocking nACh receptors on post-synaptic neuron.
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What nerves are typically effected by myasthenia gravis?
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Cranial nerves
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What drug intervention can be used to treat myasthenia gravis?
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acetylcholinesterase inhibitors
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Which myasthenic disorder (gravis or syndrome) will have affected MEPPs?
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Myasthenia gravis: reduction in nACh receptors
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Which myasthenic disorder effects the depth of the junctional folds (gravis or syndrome)?
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Myasthenia gravis: reduction in junctional fold and an increase in synaptic space
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What is the difference is paralysis associated with botulinum and tetanus toxin?
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Botulinum toxin causes flaccid paralysis
Tetanus toxin causes spastic paralysis |
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What protein is targeted by tetanus toxin?
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synaptobrevin on GABA/glycine vesicles
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What toxin target NMJs?
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Botulinum
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What proteins are targeted by botulinum?
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Synaptobrevin
Syntaxin SNAP-25 |
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What bacteria produces tetanus toxin?
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Clostridium
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What toxin would cause the loss of synaptic inhibition on spinal motor neurons?
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Tetanus toxin
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What toxin would cause inhibition of ACh release into the NMJ?
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Botulinum toxin
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What toxin would cause hyper-excitation of skeletal muscles?
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Tetanus
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What bacteria produce botulinum toxin?
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Clostridium
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What venoms cause the complete depletion of ACh?
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Black widow and scorpion venom
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What is the effect of tetrodotoxin and what animal produces it?
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Blocks Na channels
Produced by the puffer fish |
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What animal toxin can bind specifically to ACh receptors?
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Cobra toxin
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What is the action of the alpha bungarotoxin?
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Irreversibly binds nicotinic ACh receptors
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What is the effect of conotoxin?
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blocks Ca channels
blocks Na channels blocks glutamate receptors blocks ACh receptors |
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What is the effect of Tabun, Soman and Saran nerve gases?
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They block the action of acetylcholinesterase
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What drug is used to reactivate the acetylcholinesterase activity following nerve gas exposure?
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3-PAMC1
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