What is micturition?

Micturition refers specifically to the process of expelling urine from the bladder. This process involves the contraction of the bladder muscles and the relaxation of the sphincters, allowing urine to flow out of the bladder and through the urethra. It is a vital function of the urinary system, enabling the body to remove waste and regulate fluid balance.

Understanding this concept is essential for grasping the overall function of the urinary system, which includes the formation, storage, and elimination of urine. In contrast, the other options focus on different aspects of kidney function rather than the act of urination itself. For instance, urine formation occurs in the kidneys, reabsorption of water is part of the kidney's intricate process to maintain homeostasis, and filtration in the glomerulus is a critical first step in urine formation, but none of these accurately describes micturition. Thus, the chosen option correctly identifies the action associated with urination.