Final answer:
Renal K+ excretion is independent of changes in extracellular fluid volume due to the strict control of serum potassium levels by homeostatic mechanisms. This regulation is important to maintain a balance of potassium levels in the body.
Step-by-step explanation:
Renal K+ excretion is independent of changes in extracellular fluid volume due to the strict control of serum potassium levels by homeostatic mechanisms. Renal potassium excretion is primarily controlled by sodium delivery to the distal nephron and urine flow, vasopressin levels, acid-base status, and the renin-angiotensin-aldosterone system. When more sodium is reabsorbed, more potassium is secreted, and when less sodium is reabsorbed, more potassium is retained. This regulation is important to maintain a balance of potassium levels in the body.