The kidneys are two fist-sized organs on opposite sides of the body located near the lower spine. Each one is made up of a million nephrons which act as the filters for all of the fluid in the body. Every day, the kidneys filter about 200 quarts of fluid (up to 150 quarts of blood) and produce about 2 quarts of urine. Urine is the result of waste removal from blood and water. One part of the nephron, the glomerulus, allows fluid and waste products to pass through it while keeping out blood cells and proteins. Then, they pass through the tubules. The tubules return necessary minerals back to the bloodstream and send the waste to the bladder, where it stays for 1 to 8 hours before excretion.
The kidneys keep the body’s blood in check by making sure it has the correct concentration of fluids and various substances. It makes sure that electrolytes, hormones, and drugs remain at a healthy concentration in the body. They control the production of red blood cells, release hormones that regulate blood pressure, and keeps bones healthy by producing a form of vitamin D. Vitamin D helps the body absorb calcium, which is a main constituent in bones (in calcium carbonate and calcium phosphate).
Blockages: kidney stones
Chemicals crystallize in the urine, starting off as stones smaller than a grain of sand. These can gradually grow to larger than an inch. The pain is caused by their obstruction in the ureter and the resulting pressure from the urine pushing against it. Some causes of kidney stones could include heredity, diet, medications (especially diuretics), and hydration.