A patient comes to the emergency room shortly after dining on raw oysters at a l

Question

A patient comes to the emergency room shortly after dining on raw oysters at a local restaurant. She complains that she had tingling sensations that started in her lips and mouth and has spread to the face, neck, arms, fingers, and legs. The tingling soon gave way to numbness and a lack of movement and coordination. The doctor makes intracellular recordings of the neurons in the patients arm and notices a normal resting membrane potential, but the neurons do not generate action potentials when stimulated to threshold. The doctor determines that she has been poisoned by a toxin called saxitoxin. Answer the questions 1a-1b below regarding this case.

a. Explain the physiological mechanism(s) affected by this toxin that results in the inability of this patient’s neurons to fire an action potential even though stimulated to threshold.

b. Explain why this patient presents with normal resting membrane potentials.

c. Explain why this patient is experiencing a lack of movement.

Explanation / Answer

a.Actually patient after consuming oyster she affected by a toxin called saxitoxin.Saxitoxin mainly a neurotoxin. It affects neurons. It acts as a specifically sodium blocker, or it mainly acts on the voltage gated sodium channels of neurons.This voltage gated sodium channel are essential for the propagation of action potential.In this case saxitoxin blocks the voltage gated sodium channel. and as a results in the inability of this patient neurons to fire an action potential even though stimulated to threshold.

b.This patient presents with normal resting membrane potentials because saxitoxin block votage gated sodium channel without affecting potassium channel. so this toxin block sodium to create action potential but concentration of potassium ion remain same.

c.This patient is experiencing a lack of movement is result of ingestion of harmful levels of saxitoxin is known as paralytic selfish poisoning opr PSP.This toxin block the voltage gated sodium channel. which is preventing normal cellular function of patients body and leading to paralysis.

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