What is the name of the process where the nephron removes water and solutes from tubular fluid and returns them to the bloodstream?

• A. Filtration
• B. Tubular reabsorption
• C. Tubular secretion
• D. Excretion

Answer: (B)

The process where the nephron removes water and solutes from tubular fluid and returns them to the bloodstream is known as tubular reabsorption. This is a crucial function of the nephron, which is the basic structural and functional unit of the kidney.

During tubular reabsorption, specific substances such as nutrients, electrolytes, and water are selectively transported from the renal tubules back into the peri-tubular capillaries. This is essential for maintaining homeostasis and ensuring that beneficial components that were initially filtered out of the blood are reclaimed. For instance, glucose and amino acids are typically reabsorbed almost entirely, while the reabsorption of water and ions like sodium is finely regulated according to the body’s needs.

This process occurs after initial filtration in the glomerulus, where blood plasma is filtered into the nephron and leads to the formation of urine. Therefore, tubular reabsorption plays a vital role in regulating body fluid levels, electrolyte balance, and-the overall composition of urine.