During micturition, the urinary bladder …………. and the urethral sphincters ………..

Explanation

**Step-by-Step Solution:**

1. **Understanding Micturition**: Micturition is the process of expelling urine from the urinary bladder. It involves a series of coordinated muscular contractions and relaxations.

2. **Function of the Urinary Bladder**: During micturition, the urinary bladder, which stores urine, must contract. This contraction is necessary to push the urine out of the bladder and into the urethra.

3. **Role of Urethral Sphincters**: The urethral sphincters are muscles that control the release of urine from the bladder. During micturition, these sphincters must relax to allow urine to flow out of the bladder through the urethra.

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