Final answer:
The urinary bladder is a hollow, muscular sac that collects urine from the kidneys via the ureters and stores it until urination. Urine exits through the urethra, which performs differently in males and females because of reproductive roles in males. The bladder and urinary system also provide protection and infection prevention.
Step-by-step explanation:
The membranous sac in humans and other animals that collects urine secreted by the kidneys is called the urinary bladder. This organ is a hollow, muscular, and stretchy structure located on the pelvic floor. Urine is transported from the kidneys through the ureters, enters the bladder through ureteral openings, and is stored there until it is ready to be expelled from the body. The process of eliminating urine involves it passing through the internal urethral sphincter, into the urethra, and out of the body during urination.
The bladder's capacity to store urine can be influenced by various factors, such as compression during late pregnancy in females which results in increased frequency of urination. The bladder's walls are made of transitional epithelium that allows it to expand as it fills and muscular layers that contract to push urine into the urethra during the act of micturition. In males, the urethra also serves a dual function in the excretion of semen.
The entire urinary system, including the bladder and urethra, serves not only to store and transport urine but also to protect bodily tissues from damage, prevent infections, and in males, to facilitate reproductive functions.