Final answer:
The proximal convoluted tubule is where the majority of absorption occurs in the nephron, reabsorbing water, nutrients, sodium, and potassium. This is followed by further water reabsorption in the loop of Henle, the distal convoluted tubule, and final adjustments in the collecting ducts under hormonal control.
Step-by-step explanation:
Where is Most Absorption in the Nephron?
The majority of fluid and solute absorption in the nephron occurs in the proximal convoluted tubule (PCT), where up to 67% of water, sodium (Na+), and potassium (K+) is reabsorbed and returned to the circulation. Almost 100% of glucose, amino acids, and other nutrients are reabsorbed here as well. Following the PCT, the loop of Henle takes part in the reabsorption process, particularly in concentrating the urine.
The distal convoluted tubule (DCT) recovers an additional 10-15 percent of filtered water before it reaches the collecting ducts, where the final adjustment of water reabsorption occurs under the influence of antidiuretic hormone (ADH), depending on the body's hydration status. The hormones ADH and aldosterone are crucial in this tightly regulated process, as they directly influence water and electrolyte balance in the later stages of the nephron.