Neuromuscular Physiology
What three main structures form the neuromuscular junction?
What are presynaptic nerve terminal, synaptic cleft (with basal lamina and AChE), and postsynaptic muscle membrane?
What is the only depolarizing neuromuscular blocker in clinical use?
What is succinylcholine (suxamethonium)?
What two chemical classes comprise the nondepolarizing NMBDs?
What are the steroidal and benzylisoquinolinium classes?
What cardiac effect may occur after a second dose of succinylcholine, and how can it be prevented?
What is sinus bradycardia prevented with atropine?
Name three acetylcholinesterase inhibitors used to reverse nondepolarizing block.
What are neostigmine, edrophonium, and pyridostigmine?
Which enzyme rapidly hydrolyzes acetylcholine at the NMJ?
What is acetylcholinesterase?
How does succinylcholine cause muscle fasciculations before paralysis?
What is by initially depolarizing the motor endplate through prolonged opening of AChR ion channels?
Which mechanism terminates atracurium’s action independent of organ function?
What is Hofmann elimination?
Why is succinylcholine contraindicated in burn or denervation patients?
What is because of upregulation of extrajunctional ACh receptors leading to severe hyperkalemia?
What is meant by the “ceiling effect” of neostigmine?
What is that once acetylcholinesterase is fully inhibited, additional drug provides no further benefit?
Which subunit replaces the ε subunit in fetal receptors?
What are γ receptors?
What enzyme metabolizes succinylcholine?
What is butyrylcholinesterase (plasma cholinesterase)?
Which steroidal NMBD has the fastest onset of action?
What is rocuronium?
Which NMBDs release histamine (name 2)?
What are mivacurium, atracurium, and tubocurarine?
Which anticholinergic is paired with neostigmine and why?
What is glycopyrrolate, to block muscarinic effects and match neostigmine’s onset?
What two receptors mediate excitation–contraction coupling in skeletal muscle?
What are Dihydropyridine receptor (DHPR) and ryanodine receptor type 1 (RyR1)?
Name three conditions that decrease butyrylcholinesterase activity.
What are pregnancy, liver disease, and malnutrition (also burns or certain drugs)?
Rank these NMBDs by potency (high → low): cisatracurium, vecuronium, rocuronium.
What is cisatracurium > vecuronium > rocuronium?
Which drug class accounts for most intra-anesthetic anaphylaxis cases?
What are neuromuscular-blocking drugs (NMBDs)?
How does sugammadex work?
It encapsulates steroidal NMBDs (rocuronium > vecuronium) in a 1 : 1 complex to reverse block?
Mutations in which receptor gene are linked to malignant hyperthermia?
What is the Ryanodine receptor type 1 (RyR1) gene?
What is the usual IV intubating dose of succinylcholine?
What is 1.0 mg/kg IV?
How do inhalational anesthetics affect nondepolarizing block?
What is that they potentiate the block?
Which rare metabolic crisis is triggered by succinylcholine and inhalational agents, and what drug treats it?
What is malignant hyperthermia treated with dantrolene (or Ryanodex)?
What train-of-four (TOF) ratio defines adequate recovery from neuromuscular blockade?
What is a TOF ratio of 0.9 or greater?