This episode examines the core physiologic and quantitative principles of renal function, focusing on glomerular filtration dynamics governed by Starling forces, the precise calculation of glomerular filtration rate (GFR) and renal plasma flow (RPF) using clearance techniques, and the mechanisms of the major diuretic classes. It integrates hemodynamic principles with tubular transport to clarify how alterations in these parameters drive clinical pathology. As the foundational deep dive into renal physiology, this content establishes the mechanistic framework essential for understanding fluid-electrolyte disorders, heart failure, and acid-base disturbances across multiple organ systems.