What is a primary function of the kidneys in urinary elimination?

• A. To store urine before voiding.
• B. To transport urine to the bladder.
• C. To filter the blood, form urine, regulate fluid and electrolyte balance, and excrete wastes and drugs.
• D. To produce hormones that regulate blood sugar.

Answer: (C)

The kidneys’ main role in urinary elimination is to filter the blood to form urine, while regulating fluid and electrolyte balance and excreting wastes and drugs. Blood is filtered in the glomeruli, and as the filtrate travels through the tubules, the body reabsorbs what it needs (like water and essential electrolytes) and secretes what isn’t needed, producing urine. This process controls urine volume and composition, keeps electrolyte levels stable, and maintains acid-base balance, all while helping eliminate wastes and drug metabolites. Urine is then transported from the kidneys to the bladder by the ureters for storageUntil voiding. The bladder, not the kidneys, stores urine, and the pancreas—not the kidneys—regulates blood sugar.