Chapter 11.4, Problem 1LO

Summary Introduction

To summarize:

The process by which the kidney maintains the water-salt balance of the body.

Introduction:

The water-salt balance in the kidney is maintained by the secretion of aldosterone from the adrenal gland. It helps in the exchange of ions across the membrane of the cells in the distal convoluted tubule. The potassium ions are secreted out and the retention and reabsorption of sodium ions takes place. The decrease in the pressure inside the blood vessels causes the secretion of renin from the juxtaglomerular apparatus cells in the kidney. It leads to reabsorption of the ions in the kidney tubules.

The release of the anti-diuretic hormone (ADH) from the posterior pituitary causes the retention of water molecules in the distal collecting tubules and the collecting duct. Atrial natriuretic hormone (ANH) is released from the cardiac cells and inhibits the release of the aldosterone and antidiuretic hormone. This causes the excretion of the sodium ions and water molecules from the nephrons in the kidney.