The Action Potential and Neuromuscular Junction Problem I : Linda was a bit nerv
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Question
The Action Potential and Neuromuscular Junction
Problem I: Linda was a bit nervous going to the doctor’s office but she knew that she had to go because of the chronic fatigue she was experiencing. In addition, she was now starting to notice muscle weakness on her face as well as her left eyelid was drooping in the late afternoon. She simply couldn’t explain the symptoms away. Sitting in the doctor’s office waiting to be called, Linda thought she was being silly as she imagined it to be nothing more than taking too many courses in the semester. Still, there was that nagging concern in the back of her mind.
Finally, the nurse called her back and took her vitals. Her BP was 118/69 and her weight was a reasonable 127 lbs for a 5’ 5” person. The doctor shows up in a few minutes and talks with Linda extensively about her symptoms. He suggests a single fiber electromyography. Linda leaves the office and takes the ex later at a nearby hospital. There are many possibilities the doctor is considering to explain the muscle weakness Linda is experiencing.
There are 3 mechanisms found just in the synapse that could explain Linda’s symptoms. Describe them and how they may relate to Linda’s issues.1. (5 pts) Presynaptic action potential:
2. (5 pts) ACh quantity released:
3. (5 pts) Activity of Acetylcholinesterase:
With the results in hand, the doctor meets with Linda again explains to her it is most likely myasthenia gravis (MG). He then prescribes neostigmine and asks Linda to return in 2 weeks for a follow up visit.
4. (10 pts) Describe how neostigmine works and how it may help Linda’s symptoms.
5. (10 pts) How would the botulinum toxin affect Linda’s disorder? Be thorough in your response.
Problem II: Alec was just minding his own business one day when he entered his kitchen. Unbeknownst to him, a heavy glass light cover was loose and, precisely when he walked under it, it dropped on his head. Alec was a bit dazed but otherwise felt fine afterwards. A couple of weeks later, Alec began experiencing seizures. He went to the doctor who decided to go ahead and perform the necessary tests to confirm his diagnosis.
1. (5 pts) What is epilepsy?
2. (10 pts) Describe how to conduct an EEG and MRI that are commonly used to diagnose epilepsy.
3. A. (10 pts) Would a glutamate agonist or antagonist be an effective treatment for epilepsy? Explain.
B. (10 pts) Would a GABA receptor agonist or antagonist be an effective treatment for epilepsy? Explain.
Problem III: Several neurotoxins have dramatic effect on the action potential or at the neuromuscular junction. In each of the following selections, state how they affect action potential generation or neuro-excitation of skeletal muscle. (5 pts ea)
1. Tetrodotoxin (TTX):
2. -conotoxin:
3. Tetanus toxin:
4. Caramboxin (CBX):
5. Curare:
6. Tetraethylammonium TEA):
Explanation / Answer
Problem II
1. Epilepsy is the abnormal & excessive electrical activity (action potential) happening in the brain cells, which results in seizures. Epilepsy can be random and of different characteristics. The seizures are of different type tonic-clonic, tonic, clonic, myoclonic, absence, and atonic seizures.
2. The Electroencephalogram (EEG) is the test performed to monitor and record the electrical activity of the brain. Similar to Electrocardiogram (ECG or EKG), the electrical activity of the brain is captured non invasively through electrodes. The electrode captures the impulses & represents it as waves. The abnormal waveform represents the disorder in conduction.
Magnetic Resonance Imaging (MRI) is another technique using strong magnetic fields, radio waves, and field gradients to visualize the brain cells.
3.Glutamate agonist or antagonist: Glutamate is also known as glutamic acid, a neurotransmitter which agonizes or antagonizes one or more of the glutamate receptors.
Glutamate agonist agonizes glutamate receptors and enhances the transfer of electrical signals between neurons in the brain and in the spinal column. Eg. NMDA receptor agonists.
Glumate antagonist reacts with the receptor & suppress the electrical signals, majorly used as anesthesia.
Eg. NMDA receptor antagonist such as Ketamine.
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