The normal human kidney has three major functions: 1, the generation of urine, excretion of metabolic end products products. The body produces a variety of waste in the metabolic process, the vast majority of waste through the glomerular blood filtration, renal tubular secretion, and excreted with the urine. 2.Maintain water and salt balance and acid-base balance in the body. Through glomerular filtration, renal tubular reabsorption and secretion, the kidney excretes excess water, regulates acid-base balance, maintains electrolyte stability and maintains the stability of the entire internal environment of the body. 3.Endocrine function. ① Secrete renin, prostaglandins, kinins, etc. It regulates blood pressure through renin-angiotensin-aldosterone system (RAAS system) and kinesin-bradykinin-prostaglandin system. (ii) Synthesis and secretion of human erythropoietin to stimulate bone marrow hematopoiesis. (iii) Secrete 1a-hydroxylase to regulate calcium and phosphorus metabolism.