Which of the following would NOT inhibit micturition?

• A. Activation of the parasympathetic nervous system
• B. Increased sympathetic nervous system activity
• C. Stimulation of the pontine storage center
• D. Contraction of the external urethral sphincter

Answer: (A)

Verified step by step guidance

1. Understand the process of micturition: Micturition is the act of urination, controlled by the coordination of the nervous system and muscles. It involves the parasympathetic nervous system, sympathetic nervous system, and somatic control of the external urethral sphincter.
2. Review the role of the parasympathetic nervous system: The parasympathetic nervous system promotes bladder contraction and relaxation of the internal urethral sphincter, facilitating micturition. Activation of this system would encourage urination, not inhibit it.
3. Examine the role of the sympathetic nervous system: The sympathetic nervous system inhibits micturition by relaxing the bladder wall and contracting the internal urethral sphincter, preventing urine flow.
4. Analyze the function of the pontine storage center: The pontine storage center in the brainstem inhibits micturition by promoting storage of urine. It does so by coordinating the contraction of the external urethral sphincter and inhibiting parasympathetic activity.
5. Consider the contraction of the external urethral sphincter: The external urethral sphincter is under voluntary control and its contraction prevents urine from leaving the bladder, thereby inhibiting micturition.