What is the primary role of the detrusor muscle during micturition?

The primary role of the detrusor muscle during micturition is to contract to expel urine from the bladder. This smooth muscle, which lines the bladder wall, plays a crucial role in the process of urination. When the bladder fills with urine, nerve signals indicate that it's time to void. The detrusor muscle responds by contracting, which increases the pressure within the bladder and helps propel urine into the urethra for excretion.

Other functions related to urination, such as urine storage and the relaxation of muscles, are managed by different components of the urinary system. For instance, the detrusor muscle remains relaxed during the filling phase to allow the storage of urine. Similarly, while the impulse control is important for deciding when to urinate, it is not the primary function of the detrusor muscle itself. Thus, the contraction of the detrusor muscle during micturition is essential for the effective expulsion of urine from the body.