What is the main functional unit of the kidney?

The nephron is recognized as the main functional unit of the kidney, and this is primarily because it is responsible for urine formation and the regulation of various bodily functions. Each kidney contains approximately a million nephrons, each composed of a renal corpuscle (which includes the glomerulus) and a renal tubule.

The glomerulus, while an important part of the nephron, mainly serves as a site for blood filtration. In contrast, the nephron encompasses the entire process of filtration, reabsorption, secretion, and excretion that occurs throughout its structure. It plays a critical role in maintaining homeostasis, managing electrolyte balance, regulating blood pressure, and controlling the body’s fluid balance.

The renal pelvis is more of a collecting basin for urine before it moves to the ureter, and the ureter is responsible for transporting urine from the kidneys to the bladder. Therefore, although the glomerulus, renal pelvis, and ureter have significant roles within the urinary system, it is the nephron that carries out the key functions required for renal operation and overall body homeostasis.