Mechanism of Urine Formation

Regulation of Urine Concentration and Volume

Urine formation is a complex physiological process crucial for maintaining homeostasis in the body. The kidneys regulate urine concentration and volume through filtration, reabsorption, secretion, and excretion.

1. Filtration Process

Blood enters the glomerulus, where filtration occurs, allowing essential solutes and fluids to pass into the renal tubules.

2. Reabsorption and Secretion

Key solutes such as sodium, potassium, and glucose are reabsorbed, while waste products like urea and creatinine are secreted into the urine.

3. Regulation by Hormones

• Antidiuretic Hormone (ADH) increases water reabsorption, leading to concentrated urine.
• Aldosterone regulates sodium and potassium balance, affecting urine volume.

4. Role of Osmoregulation

The kidneys maintain electrolyte balance and regulate urine osmolarity, ensuring optimal hydration levels.