Question

Explain physiologially, how urine volume and potassium concentration are altered by the presence/absensce of aldosterone and antidiuretic hormoen both alone and together.

Answer 1

Anti-diuretic hormone or ADH is a hormone which increases the permeability of the tubules to increase the reabsorption of water by adding aquaporins in the membranes of the tubules and aldosterone- a steroid hormone which increases the reabsorption of sodium and retention of water in the tubules.

1. In the low concentration of water- more water is absorbed from the kidney due to the production of ADH and aldosterone which reduces the volume of water in the urine and thus the low volume of urine is produced and the potassium ions retain in the body.

2. In high concentration of water- ADH and aldosterone are not produced and the urine is produced in a normal amount. Some potassium ions can be released.