What initiates the micturition reflex?
A)The external urethral sphincter relaxes.
B)The internal urethral sphincter relaxes.
C)Parasympathetic efferent fibers stimulate the contraction of the detrusor muscle.
D)Stretch receptors in the wall of the urinary bladder signal the sacral region of the spinal cord.

Question

Quizplus · Accepted Answer

The micturition reflex is initiated by stretch receptors in the wall of the urinary bladder that signal the sacral region of the spinal cord. This causes the detrusor muscle to contract and the internal urethral sphincter to relax, leading to the urge to urinate. The external urethral sphincter is under voluntary control and is relaxed when a person intentionally decides to urinate. Parasympathetic efferent fibers also play a role in micturition by stimulating the contraction of the detrusor muscle, but they are not the initial trigger for the reflex.

What Initiates the Micturition Reflex