Question

Sodium mostly reabsorbed from glome-rular filtrate by:

• A. Proximal convoluted tubule
• B. Collecting duct
• C. Distal convoluted tubule
• D. Vasa efferentia

Answer 1

Answer:

A. Proximal convoluted tubule

The proximal convoluted tubule (PCT) reabsorbs the majority of sodium from glomerular filtrate: Percentage reabsorbed: The PCT reabsorbs around 70% of the sodium filtered by the glomerulus. Role in blood pressure and plasma volume: The PCT's sodium reabsorption helps regulate blood pressure and plasma volume. Coupled with water reabsorption: Sodium reabsorption is closely linked with water reabsorption, meaning that when sodium moves, water follows. The PCT reabsorbs sodium through a process called tubular reabsorption. In this process, the nephron removes water and solutes from the tubular fluid and returns them to the blood.