Which term refers to the structural and functional unit of the kidney?

The term that refers to the structural and functional unit of the kidney is the nephron. Each kidney contains approximately one million nephrons, which are responsible for filtering blood, removing waste, and reabsorbing essential substances to maintain fluid and electrolyte balance in the body.

The nephron consists of several components, including the glomerulus, where blood filtration occurs, and tubules that process the filtrate into urine. However, the nephron is recognized as the complete unit that carries out the essential functions of the kidney, including filtration, secretion, and reabsorption.

Other options relate to specific parts or functions within the nephron but do not represent the whole structural and functional unit. The nephron loop, for example, is a portion of the nephron that plays a role in the concentration of urine, but on its own, it does not encompass the entire functional capabilities of the nephron. Similarly, the glomerulus and collecting duct are important parts of the nephron but do not represent the complete unit responsible for kidney function. Hence, identifying the nephron as the structural and functional unit captures its essential role in renal physiology.