The urinary system is like one big filter because it removes excess fluid and unusable substances from the bloodstream. This liquid waste product filters out of the body in the form of urine. Kidneys produce the urine which is soon after stored in the bladder. The urinary system's primary purpose is to maintain a balance between acid and base, and water and salt in the body. Another organ that is also involved in excretion is the urethra, but the kidneys are the most important.
Imagine two big kidney beans that are about fist-sized. Now imagine these beans covered in a layer of tissue and fat, and located above your waistline. They are above the waist and toward the back of your torso. The ribcage shields these organs from physical damage. A healthy diet can help shield them from internal damage. Kidney damage happens over time. Sometimes, it is hard to notice any problems until later in life. One cause of kidney damage is heavy alcohol consumption.