Sketch and label the structure of nephrons.

Hint: Nephrons are the complex microscopic cells present in the urinary system. Its function is to produce urine and remove waste and excess substances from the blood. Complete Answer: Nephron is the structural and functional unit of Kidney. Its main function is to convert blood into urine by filtration, reabsorption, secretion and excretion of useful and harmful substances present in the blood. The nephron in the mammalian kidney is a long tubular structure which consists of- 1) Bowman’s Capsule: This is a cup-like structure from which the renal tubule extents. Ultrafiltration takes place at the Bowman’s capsule. 2) Glomerulus: These are small tufts of capillaries through which blood flows in high pressure. It receives blood from afferent arterioles. 3) Loop of Henle: It is a hair-pin like structure. It has a thin ascending limb and thick ascending limb. Through the loop of Henle, fluid filtered through glomerulus reaches the collecting duct. Re-absorption of useful substances takes place here. 4) Distal convoluted tubule: The cell linings of these tubules have many mitochondria which produce energy required for active transport. Its function is to reabsorb calcium ions. 5) Proximal convoluted tubule: It is the part of the nephron when salt water and organic solutes like glucose and amino acids are filtered. 6) Collecting tubule: It is the final segment of the tubules before entering the collecting duct. In these tubules reabsorption of water takes place. Note: Nephron is the structural and functional unit of Kidney. Its main function is to regulate water and other soluble substances in the blood. It helps in maintaining homeostasis of blood volume, and blood pressure by excreting harmful substances and reabsorbing useful ones.