In which part of the nephron, does active reabsorption of sodium occur?

Active reabsorption of sodium occurs primarily in the Proximal Convoluted Tubule (PCT) and the Loop of Henle.

The PCT reabsorbs the majority of the filtered load of sodium as well as other solutes like glucose and amino acids.

The Loop of Henle, a U-shaped portion of the nephron, plays a crucial role in regulating salt and water balance. It generates a steep sodium ion concentration gradient that allows for passive sodium reabsorption through the thin descending limb.

The Distal Convoluted Tubule and Collecting Duct also play a role in sodium reabsorption, but to a lesser extent than the PCT and Loop of Henle.