What do we call the movement of solutes from blood to filtrate anywhere other than Bowman's capsule?

The movement of solutes from blood to filtrate at locations other than Bowman's capsule is referred to as secretion. This process occurs mainly in the renal tubules, where specific substances are transported from the peritubular capillaries into the tubular fluid. This allows the body to regulate the levels of certain ions, metabolites, and drugs more precisely, helping maintain homeostasis by expelling excess or unwanted substances from the bloodstream.

In the kidneys, filtration occurs at Bowman's capsule, where blood plasma is filtered to form the initial filtrate. Absorption refers to the process by which substances are taken back from the filtrate into the bloodstream, primarily in the proximal convoluted tubule and other parts of the nephron. Excretion is the final step in urine formation, where urine is eliminated from the body after all processing in the nephron has occurred. Secretion specifically emphasizes the active transfer of solutes from blood to filtrate, distinct from filtration and reabsorption processes.