What is the term used to describe the process of emptying urine from the bladder?

Micturition refers specifically to the process of emptying urine from the bladder. This physiological mechanism involves the contraction of the bladder muscles and the relaxation of the sphincter muscles, allowing urine to flow from the bladder through the urethra and out of the body. Micturition is a crucial function of the urinary system that enables the regulation of fluid balance and waste elimination.

The other choices describe different processes. Excretion is a broader term that covers the removal of waste products from the body, which includes urine as well as other forms of waste from various bodily systems. Defecation focuses specifically on the elimination of solid waste from the digestive tract, while filtration generally refers to the process of filtering substances, which occurs in the kidneys during urine production but does not specifically relate to the act of urinating. Thus, micturition accurately describes the act of emptying urine, differentiating it from these other processes.