Myasthenia gravis is an autoimmune disorder in which the body produces antibodies for the individual's acetylcholine receptors. Antibodies are proteins produced by the B cells of the immune system which bind to foreign cells to render them inoperable. Clinical manifestations of this condition include exertional fatigue and weakness which improves upon rest and returns upon activity.
The poison from the black widow, α-Latrotoxin, binds to presynaptic terminals, causing spontaneous fusion of the synaptic vesicles with the presynaptic membrane, presumably by opening calcium channels in the presynaptic terminal which causes fusion of the synaptic vesicles with the membrane.
The toxin found in the bacteria Clostridium botulinum directly prevents neurotransmitter release at the neuromuscular junction. Manifestations of botulinum toxin include flaccid paralysis.
Tests were performed on three individuals, each presenting with conditions of one of the above conditions. The tests included (1) testing the motor neurons leading to muscles to determine whether action potentials were being generated, (2) analyzing the synaptic cleft at the neuromuscular junction to assess the presence of acetylcholine, and analyzing the sarcolemma of the muscles to look for presence or absence of action potentials. The following were the findings for the three individuals:
Test
Patient A :
AP in Neuron? YES My answer: botulism**
ACh in cleft? NO
AP in Muscle? NO
Patient B :
AP in Neuron? YES My answer: Myasthnia gravis**
ACh in cleft? YES
AP in Muscle? NO
Patient C : My answer: Black widow toxin**
AP in Neuron? NO
ACh in cleft? YES
AP in Muscle? YES
From the above information, please determine which patient was suffering from the conditions described above (i.e., Myasthenia Gravis, botulism poison or black widow spider toxin), and cite the reason(s) for your decision.
********My answers are:********
Patient A has botulinum posion.
Patient B has Myasthenia gravis.
Patient C has black widow spider toxin.
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