Mechanism that does not contribute to counter current multiplier in nephron

Ref. Guyton. 13th edition. Page. 435 Countercurrent multiplication in the kidneys is the process of using energy to generate an osmotic gradient that enables you to reabsorb water from the tubular fluid and produce concentrated urine.   The three segments of the loops of Henle have different characteristics that enable countercurrent multiplication. The thin descending limb is passively permeable to both water and small solutes such as sodium chloride and urea. The tubular fluid becomes steadily more concentrated or hyperosmotic (compared to blood) as it travels down the thin descending limb of the tubule. The thin ascending limb is passively permeable to small solutes, but impermeable to water, which means water cannot escape from this part of the loop. The tubular fluid becomes steadily more dilute or hyposmotic as it moves up the ascending limb of the tubule. The thick ascending limb actively reabsorbs sodium, potassium and chloride. this segment is also impermeable to water, which again means that water cannot escape from this part of the loop. This segment is sometimes called the “diluting segment”