How is urine produced?
The urine formation involves three steps: (a) Glomerular filtration: Nitrogenous wastes, glucose water, amino acid are filtered from the blood in blood capillaries into Bowman Capsule of the nephrons. (b) Selective reasbsorption: Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water are selectively reabsorbed back by capillaries surrounding the nephrons. (c) Tubular secretion: Some ions like K+, H+, etc. are secreted into the tubule which opens up into the collecting duct.
