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Question #47418
The Question
In late-stage carcinomas, metastatic cells often infiltrate the perineural space (perineural invasion), causing severe chronic neuropathic pain. Based on the principles of neural conduction, how does the localized tumor microenvironment most likely induce this ectopic neural firing?
Options
- A.
By increasing the resting efflux of K+ ions, leading to a prolonged hyperpolarized state of the axolemma.
- B.
By lowering the threshold potential of the peripheral neurons, facilitating the premature opening of voltage-gated Na+ channels.
- C.
By completely inhibiting the Na+/K+ ATPase pump, which directly increases the amplitude of the action potentials.
- D.
By physically compressing the nodes of Ranvier, thereby converting saltatory conduction into continuous conduction.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Voltage_Gated_Na_Channels|Metastasis|Tumor_Suppression
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The relationship between threshold potential and neuronal excitability.
Students often mistakenly associate nerve damage or compression solely with a loss of function (numbness/conduction block).
However, in cancer-induced neuropathic pain, the microenvironment lowers the threshold potential, causing hyperexcitability and ectopic firing.
The trap lies in confusing factors that affect conduction speed or amplitude with those that initiate the action potential.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Neural Control and Coordination - Class 11 |
| Concept | Action Potential Threshold Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |