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Physiology question - jayblue22
#1
A 31-year-old man comes to the physician because of several months of recurrent abdominal pain and diarrhea. 6 months ago, he traveled to Lake superior for a fishing trip with his friends during which they often ate their day’s catch for dinner. Physical examination shows pallor. Laboratory studies show macrocytic anemia with eosinophilia. A peripheral blood smear shows hypochromic red blood cells with megaloblast and hyperpigmented neutrophils. A cestode infection is suspected and a drug is prescribed that kills cestodes by inducing uncontrollable muscle spasms in the parasite. The drug prescribed for this patient most likely acts by which of the following mechanisms of action?
a. Blockage of myosin binding sites
b. Increased sodium efflux from the sarcoplasm
c. Increased potassium efflux from the sarcoplasm
d. Increased calcium influx into the sarcoplasm
e. Blockage of non-dihydropyridine calcium channels
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#2
Answer: Increase Calcium influx into sarcoplasm
Diagnosis: Diphyllobothrium latum infection - vit-b12 deficiency causing Megaloblastic anemia
Drug used - AntiHelminthics - praziquantel
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#3
Thank you, what about this one

An investigator is working with a mutant strain of mice that lack a consistent density of sarcolemma transverse tubules in the skeletal muscle cells. Which of the following is the most likely associated finding as a result of this abnormality?
a. Impaired binding of acetylcholine to nicotinic acetylcholine receptors
b. Decreased secretion of acetylcholine in synapse
c. Decreased expression of sacrolemmal Na+/K+ ATPase
d. Decreased entry of calcium at the presynaptic membrane
e. Impaired synchronization of cross-bridge formation
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#4
I think it should be option E; Sarcolemma T-tubules are associated with Ca+ release during contraction of muscle fibers which involves cross-bridging of Actin & Myosin filaments which requires Ca+ to activate this process.
Hence lack of T-tubules will impair that contraction mechanism.

Option A - Myasthenia Gravis related
Option B/D - Lambert-Eaton

I'm not sure of option C
Please cross check it once.
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#5
answer is D for the top
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#6
A 25-year-old body builder works out on a daily basis. He combines strength training as well as aerobic workout to his routine. He bench-presses 300 pounds. Which of the following signifies the isometric contraction of the muscle during a bench press?
a. Holding the weight stationary after the lift is complete
b. Bringing the weight down
c. When the weight is released and it drops
d. Lifting the weight up
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#7
answer is d
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