Glomerular filtration: how plasma fluid passes into Bowman’s capsule through specialized membranes.

Reabsorption: the return of vital solutes like glucose, sodium, and bicarbonate back into the blood.

Secretion: the active transport of substances such as organic acids and bases into the tubules for rapid clearance.

Excretion formula (E = F – R + S + S): the balance of filtration, reabsorption, secretion, and synthesis.

Why the kidneys filter huge amounts of solutes only to reabsorb them again, ensuring precise control of body fluid composition.

Examples of renal handling: glucose (100% reabsorbed), creatinine (fully excreted), potassium (partly reabsorbed and secreted), and more.

The structure of the glomerular membrane (endothelium, basement membrane, podocytes) and how molecular size, charge, and shape determine filtration.