<P> The nephron ( from Greek νεφρός -- nephros , meaning `` kidney '' ) is the microscopic structural and functional unit of the kidney . It is composed of a renal corpuscle and a renal tubule . The renal corpuscle consists of a tuft of capillaries called a glomerulus and an encompassing Bowman 's capsule . The renal tubule extends from the capsule . The capsule and tubule are connected and are composed of epithelial cells with a lumen . A healthy adult has 0.8 to 1.5 million nephrons in each kidney . Blood is filtered as it passes through three layers : the endothelial cells of the capillary wall , its basement membrane , and between the foot processes of the podocytes of the lining of the capsule . The tubule has adjacent peritubular capillaries that run between the descending and ascending portions of the tubule . As the fluid from the capsule flows down into the tubule , it is processed by the epithelial cells lining the tubule : water is reabsorbed and substances are exchanged ( some are added , others are removed ) ; first with the interstitial fluid outside the tubules , and then into the plasma in the adjacent peritubular capillaries through the endothelial cells lining that capillary . This process regulates the volume of body fluid as well as levels of many body substances . At the end of the tubule , the remaining fluid -- urine -- exits : it is composed of water , metabolic waste , and toxins . </P>
<P> The nephron ( from Greek νεφρός -- nephros , meaning `` kidney '' ) is the microscopic structural and functional unit of the kidney . It is composed of a renal corpuscle and a renal tubule . The renal corpuscle consists of a tuft of capillaries called a glomerulus and an encompassing Bowman 's capsule . The renal tubule extends from the capsule . The capsule and tubule are connected and are composed of epithelial cells with a lumen . A healthy adult has 0.8 to 1.5 million nephrons in each kidney . Blood is filtered as it passes through three layers : the endothelial cells of the capillary wall , its basement membrane , and between the foot processes of the podocytes of the lining of the capsule . The tubule has adjacent peritubular capillaries that run between the descending and ascending portions of the tubule . As the fluid from the capsule flows down into the tubule , it is processed by the epithelial cells lining the tubule : water is reabsorbed and substances are exchanged ( some are added , others are removed ) ; first with the interstitial fluid outside the tubules , and then into the plasma in the adjacent peritubular capillaries through the endothelial cells lining that capillary . This process regulates the volume of body fluid as well as levels of many body substances . At the end of the tubule , the remaining fluid -- urine -- exits : it is composed of water , metabolic waste , and toxins . </P>
the functional units of the kidney are called
the functional units of the kidney are called
nephron
nephron