Question

What will happen if there is no tubular reabsorption in the nephrons of the kidney?

Answer 1

Excretion is removal of nitrogenous wastes from the body in the form of urine. The nitrogenous wastes along with useful substances reach the kidney. The body cannot remove the wastes at the expense of water and electrolytes which are useful for the body. This process makes sure that the useful substances are back into the blood and only the waste is excreted.

Complete answer:
Urine formation takes place in three steps. Ultrafiltration, Selective reabsorption and tubular secretion. The urine formation takes place in the different parts of the nephron.

The filtrate that is formed per day is 180 litres/day. However, the urine released is around 1.5 liters/day. This means around 99% of the filtrate is reabsorbed by the tubules. This is an important step because the filtrate contains many useful substances that need to be sent to the blood so that those substances are used by the body.

If there will be no tubular reabsorption in nephrons the useful things would get off from the body with urine (urea and water formed urine). Selective reabsorption allows useful materials to get into capillaries again and the body will use them for further processes.

The phenomenon of secretion of metabolic wastes by the tubular cells into the filtrate is known as tubular secretion. It includes secretion of potassium, hydrogen, ammonia and some wastes like hippuric acid etc.

Note: The main advantage of this process is that the majorities of substances are reabsorbed and are back into the blood. Water too is reabsorbed and thus we urinate only 1.5 litres per day.