Describe the structure and functioning of nephrons.

Explanation

Structure of nephron. Nephron is the basic filtration unit in the kidney. It consists of a tubule which is connected with a collecting duct at one end and a cup shaped structure at the other end, called Bowman's capsule. Every Bowman's capsule contains a cluster of capillaries called glomerulus within the cup-shaped structure. The blood enters into glomerulus through afferent arteriole of renal artery and leaves it through efferent arteriole.

Basic functions of Nephrons :
(i) Filteration. Filteration of the blood takes place in Bowman's capsule in the capillaries of the glomerulus. Then this filterate passes into the tubular part of the nephron. The filterate contains glucose, amino acids urea and uric acid and a large amount of water.
(ii) Reabsorption. The filterate flows along the tubule and useful substances such as glucose, amino acids, salts and some water are re-absorbed into the blood by the capillaries surrounding the nephron tubule.
(iii) Urine. The filterate which remains after the re-absorption is called the urine, which is collected from nephron by the collecting duct to carry it to the urinary bladder and then to the urethra.