T8.6: Disease of the NMJ & Motor Unit Flashcards
Late at night, a 23 year old, Adam Mamo is vigorously reading through Craigslist confidentials. Adam comes across a listing for a one eyed snake meet and greet behind the dumpster at a local 7/11. Intrigued, Adam Mamo rushes to get there. However unbeknownst to Adam, the listing was posted by Michael Gonz, a notorious prostitute serial killer. A bystander later discovers Adam behind the 7/11 unable to move and rushes him to the hospital.
Unfortunately the attending doctor doesn’t speak arabic, so the doctor cannot find out what happened. The doctor takes note of repeated acetylcholine release and depletion.
What was Adam Mamo subjected to?
A. Alpha-Latrotoxin B. Kawa-bungarotoxin C. Beta-bungarotoxin D. Delta-tubocurarine E. Gay sex
Y’all know who wrote this question
Answer = C. Beta-bungarotoxin. It is a toxin found in the venom of snakes that initially provokes ACh release followed by ACh depletion by acting on proteins in nerve terminals involved in exocytosis.
Alpha-latrotoxin is WRONG because its mechanism causes massive release of ACh by affecting presynaptic exocytotic proteins. It is found in venom of the black widow spider.
Kawa-bungarotoxin is WRONG. Completely made up, but please appreciate my wordplay.
Delta-tubocurarine is another name for curare, which is WRONG because its mechanism blocks nAChRs.
Gay sex is a possibility as Adam Mamo is a connoisseur of such love and he couldn’t move after being found, but gay sex is WRONG because it does not cause repeated acetylcholine release and depletion.
A patient goes to the doctor do to muscle weakness. After testing of his strength it is show to increase in a waxing fashion. What would be an appropriate treatment for this patient.
A. Azatioprine B. 4-aminopyridine C. Corticosteroids D. Pyridostigmine E. Tank respirator
RFA
Ans. B- The patient has Lambert Eaton and Autoimmune disease that attacks presynaptic voltage gated Ca channels. Treatment includes 4-aminopyridine( K channel blocker) also treated with Plasma exchange and Calcium gluconate
A, C & D- All are treatments Myasthenia Gravis, which would show a waning fashion
E. Tank respirator- “the iron lung” is a treatment for Polio
A boy is brought to the pediatrician cause he struggles to get up from the floor. He has to place both hands on the ground than push up to get himself to a standing position. What is the inheritance pattern of this disease?
A.Autosomal Dominate B. X-linked Dominant C. Mitocondrial D. X-linked recessive E. Autosomal recessive
RFA
Ans. D Duchenne muscular dystrophy is being described
A patient comes to the doctor complaining of symptoms of muscle weakness and loss of coordination. Test are done and it is show that the patient has fluctuating amplitudes of EMG to repetitive stimulation. Which kind of disorder is associated with the described pattern?
A. Motor Neuron
B. Schwann Cell
C. Muscle
D. NMJ
RFA
ANS. D NMJ- disorders are the only ones (that we discussed) that will have fluctuating amplitudes of EMG
The distribution of nAChR's across a muscle fiber in an embryo is most similar to which of the following? (MG) A. Normal adult B. Person with Guillain-Barre C. Person with ALS D. Person bitten by black widow spider
C. Person with ALS
ALS is a lower motor neuron syndrome involving denervation. Denervation causes the muscle fiber to increase the expression of nAChR’s across the muscle fiber (widespread) just like in embryo’s. In a normal adult, the receptors are localized under the nerve ending.
Two of the four types of Congenital Myasthenias we discussed resulted in a greater EPP amplitude. A greater amplitude corresponds with (MG) A. Inc quantal size B. Dec quantal size C. Inc quantal content D. Dec quantal content
C. Inc quantal content
What is the mechanism by which nAChR's are removed in a person with Myasthenia Gravis? (MG) A. Exocytosis B. Endocytosis C. Pinocytosis D. Apoptosis
B. Endocytosis
nAChR’s are endocytosed into the end plate membrane and degreaded by lysosomes
Patient presents to you with asymmetrical weakness and acute flaccid paralysis of those limbs. Which of the following pairs correctly identifies this disorder?
A) Soma, ALS B) Nerve Ending, Guillain Barre C) Schwaan Cell, ALS D) Some, Poliomyelitis E) Nerve Ending, B-Bungarotoxin
Answer D - asymmetrical weakness and acute flaccid paralysis of those limbs are manifestations of polio RNA enterovirus of piconrnaviridae family that affects the soma. transmitted via fecal-oral and aorosal droplets.
B- incorrect Guillain barre is associated with schwaan cells
c wrong ALS affects soma
E- correct b bungaroo causes massive ach release then depletion
Your patient reports to because she is experience diplopia every afternoon. On your physical exam you note ptosis and you perform an EMG and discover a waning response. Which of the following is a characteristic of her disease?
A) Non Competing antibodies for ACh binding sites
B) Competing Antibodies for ACh binding sites
C) Degeneration of Crosslinks
D) Uncompetitive inhibition of ACh binding sites
E) ACh binding sight induction
Answer- A
pt has myasthenia graves which is shown by the afternoon diplopia, the ptosis, and waning emg. in this disorder antibodies do not compete for ach binding sites and cross link the nAChRs for enhanced removal
You go to a hipsters house and he has a pet goat as a pet even though he isn’t a brown guy. You go into the bathroom and unbeknownst to you the goat is pooping in the toilet and you scare him. The goat immediately goes tonic. explain what is wrong with this goat?
The goat has a defect n the Cl channel gene. when it gets scared or excited it undergoes massive depolarization and stiffens
