Describe the structure and functioning of nephrons.
Structure of nephrons: It consists of a Bowman’s capsule in which glomerulus is present (cluster of capillaries). The afferent artery brings the impure blood to nephron. The cup shaped structure (Bowman’s capsule) form a tubular part of nephron which leads to collecting duct. Working of Nephron (i) Filtration: The renal artery or afferent artery is wider and slowly it becomes a narrow tube in the glomerulus. Due to difference in the width, pressure difference is caused and water with dissolved impurities are squeezed out from the tube. It is collected in the Bowman’s capsule which is cup like structure and passes into the tube. (ii) Reabsorbtion: The above filtrate passes through the tubule where the major amount of water, glucose, amino acids are selectively reabsorbed by the capillaries which are surrounding the tubule. (iii) Urine formation: The water and impurities which is not reabsorbed is sent to a collecting duct. This filtrate contains more of dissolved nitrogenous wastes i.e. urea and hence it is termed as urine. From here the urine enters the ureter and is collected in urinary bladder.
