Pathophys
The most common target of autoantibodies in myasthenia gravis.
What is the nicotinic acetylcholine receptor?
Where is acetylcholine made in the motor neuron?
Axon terminal of motor neurons
(Bonus if you know which enzyme is responsible)
he test that shows a worsening response in MG and an incremental response in LEMS (Lambert Eaton Syndrome)
What is repetitive nerve stimulation?
The neurotransmitter released at the NMJ.
The acetylcholinesterase inhibitor that can be used both diagnostically and therapeutically in MG.
What is neostigmine?
A tumor often associated with MG.
What is a thymoma?
Where is acetylcholine vesicle made in the motor neuron?
Cell body of motor neuron in the ventral horn
The phenomenon where strength temporarily improves after repeated stimulation in Lambert-Eaton syndrome.
What is post-tetanic potentiation (or facilitation)?
The specific type of nicotinic receptor found at the NMJ.
What is the nicotinic α1 (muscle-type) receptor?
The toxin that cleaves SNARE proteins, preventing vesicle fusion.
What is botulinum toxin?
The key pathophysiological mechanism behind fatigaue in MG.
What is depletion of functional ACh receptors leading to reduced end plate potential amplitudes?
What channels determine the resting membrane potential of a muscle cell
NaK ATPase and K+ leak channels
what is a thymomectomy?
The predominant ion responsible for depolarization after ACh binds the nicotinic receptor.
What is sodium (Na⁺) influx?
The paralytic drug that produces sustained depolarization by binding nicotinic receptors.
What is succinylcholine
The paraneoplastic syndrome associated with small cell lung carcinoma that impairs NMJ transmission.
What is Lambert-Eaton myasthenic syndrome?
How to SNARE proteins bind to each other?
What is calcium cross linking V and T snares and pulls vesicles to cell membrane for fusion and relase into synaptic cleft.
The bedside test that improves ptosis in myasthenia gravis via reduced acetylcholinesterase activity at cooler temperatures.
What is the ice pack test?
The postsynaptic scaffolding protein required for stabilizing clustered ACh receptors.
What is rapsyn?
The mechanism of organophosphate poisoning at the NMJ
What is irreversible inhibition of acetylcholinesterase?
he NMJ protein targeted by antibodies in 5–10% of seronegative MG cases. (not against nictotinic receptors)
muscle-specific tyrosine kinase receptor (MuSK).
How many subunits does the nictonic receptor have?
5
The reason thymectomy can improve symptoms in some patients with MG.
What is removal of thymoma or elimination of aberrant T-cell activity driving autoimmunity?
The downstream kinase activated by agrin binding that organizes NMJ receptor clustering.
What is MuSK (muscle-specific kinase)?
The specific SNARE protein targeted by botulinum toxin type A.
What is SNAP-25?