Discuss the process of elimination of urine.

(N/A) $1$. The excretory units, known as $nephrons$, continuously form urine and transport it to the urinary bladder through the peristaltic movements of the $ureters$.
$2$. The $urinary \text{ } bladder$ serves as a temporary storage site for urine.
$3$. As the bladder fills with urine, the stretching of its walls stimulates $stretch \text{ } receptors$, which send sensory signals to the $Central \text{ } Nervous \text{ } System$ $(CNS)$.
$4$. The $CNS$ processes these signals and sends motor commands to initiate the contraction of the smooth muscles of the bladder wall while simultaneously relaxing the $urethral \text{ } sphincter$.
$5$. This coordinated action leads to the release of urine from the body, a process known as $micturition$.
$6$. The contraction and relaxation of the bladder are regulated by nerve impulses transmitted via $sympathetic$ and $parasympathetic$ nerve fibers.
$7$. An average adult human excretes approximately $1.5 \text{ } L$ of urine per day.