The kidneys are vital, bean-shaped organs located in the lumbar region, one on each side of the spine. They play a crucial role in the urinary system and in maintaining the body’s internal balance. The primary function of the kidneys is to filter the blood to remove waste and excess water, which are excreted as urine. Additionally, the kidneys regulate electrolyte levels, such as sodium, potassium, and calcium, and help maintain the body’s acid-base balance.

The kidneys also play an essential role in regulating blood pressure through the production of the hormone renin, as well as producing erythropoietin, a hormone that stimulates the production of red blood cells. Each kidney contains about one million nephrons, which are the functional units responsible for filtering the blood. When the kidneys do not function properly, overall health is compromised, leading to severe conditions such as kidney failure, which may require dialysis or a kidney transplant to sustain life.