failure). A functioning kidney is used in transplantation from a donor, preferably a close relative, to minimise its chances of rejection by the immune system of the host. Modern clinical procedures have increased the success rate of such a complicated technique. Renal calculi: Stone or insoluble mass of crystallised salts (oxalates, etc.) formed within the kidney.
Glomerulonephritis: Inflammation of glomeruli of kidney. minute (GFR). JGA, a specialised portion of the nephrons, plays a significant role in the regulation of GFR. Nearly per cent reabsorption of the filtrate takes place through different parts of the nephrons.
PCT is the major site of reabsorption and selective secretion. HL primarily helps to maintain osmolar gradient ( mOsmolL – - mOsmolL – ) within the kidney interstitium. DCT and collecting duct allow extensive reabsorption of water and certain electrolytes, which help in osmoregulation: H + , K + and NH could be secreted into the filtrate by the tubules to maintain the ionic balance and pH of body fluids. A counter current mechanism operates between the two limbs of the loop of Henle and those of vasa recta (capillary parallel to Henle’s loop).
The filtrate gets concentrated as it moves down the descending limb but is diluted by the ascending limb. Electrolytes and urea are retained in the interstitium by this arrangement. DCT and collecting duct concentrate the filtrate about four times, i.e., from mOsmolL – to mOsmolL – , an excellent mechanism of conservation of water. Urine is stored in the urinary bladder till a voluntary signal from CNS carries out its release through urethra, i.e., micturition.
Skin, lungs and liver also assist in excretion.