Answer:
Eating a meal with too much salt leads to a decrease in the water potential of blood. This fall in water potential is detected by the osmoreceptors in the hypothalamus (in brain). The hypothalamus stimulates the pituitary gland to release antidiuretic hormone (ADH). The walls of the collecting duct in the kidney become more permeable to water, hence, a greater proportion of water is reabsorbed from the urine back into the blood by osmosis.
As a result, a small volume of concentrated urine is formed.