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Question #45737
The Question
A patient suffers a severe traumatic injury that completely destroys the S2-S4 segments of the spinal cord. Based on the neural control of micturition, which of the following represents the most accurate physiological consequence?
Options
- A.
The detrusor muscle will undergo spontaneous, uncontrolled contractions due to the loss of central nervous system inhibition.
- B.
The urinary bladder will become flaccid and fail to contract due to the disruption of parasympathetic efferents.
- C.
The internal urethral sphincter will undergo somatic paralysis, leading to continuous, passive dribbling of urine.
- D.
The micturition reflex will proceed normally, but the patient will lose voluntary control over the external urethral sphincter.
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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
Sacral plexus|S2-S4 segments|Spinal cord injury
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the specific roles of the autonomic nervous system in micturition and the anatomical location of the reflex center.
Students often assume any spinal cord injury leads to a 'loss of voluntary control' while the reflex remains intact (Option D).
However, because the actual reflex center is located at S2-S4, destroying this specific segment abolishes the reflex entirely, leading to a flaccid bladder rather than an uninhibited spastic one.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Micturition Reflex Control |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |