The kidneys are located on either side of the retroperitoneal spine from about the 12th thoracic vertebra to the 3rd lumbar vertebra. The normal body has two kidneys, one on each side, and the left kidney is half to one vertebra higher than the right kidney. The kidneys weigh about 100~140g in males and are slightly lighter in females. 1. The external shape of the kidneys is like fava beans, and the renal parenchyma is divided into renal cortex, renal medulla and renal cones; the most basic structure of the kidneys is the renal unit, which is made up of about one million renal units; the renal units include renal corpuscles and renal tubules. 2. The main physiological functions of the kidneys are to regulate water electrolyte and acid-base balance, excrete metabolic products, maintain the stability of the internal environment and endocrine function. 3. The manifestations of renal diseases include fatigue and weakness, edema, proteinuria, urine color and volume, and abnormal urination. Kidney is an important organ of the human body, if you feel unwell, we suggest that you go to the nephrology department of regular hospitals for consultation and treatment, and do not blindly treat yourself.