The urinary system , composed of the kidneys, ureters, bladder, and urethra, is a vital component of the human anatomy, responsible for maintaining internal balance and waste elimination. The process of urine formation is orchestrated by the kidneys and involves glomerular filtration , tubular reabsorption, and tubular secretion.

Ureters transport urine to the bladder, a muscular reservoir, while the urethra serves as the exit pathway Tubular reabsorption selectively reclaims vital substances from this filtrate, and tubular secretion actively eliminates specific substances into the renal tubules.

tubular reabsorption — the physiological process in the kidneys by which essential substances, including water, glucose, ions, and other necessary molecules, are selectively reclaimed from the filtrate…. tubular secretion — the active transport process in the kidneys by which certain substances, including excess ions, drugs, and metabolic by-products, are selectively moved from the peritubular…. micturition reflex — an involuntary physiological response that initiates the contraction of the bladder’s detrusor muscle and relaxation of the internal urethral sphincter, facilitating the…. ureter — one of two muscular tubes that serve as conduits for transporting urine from the kidneys to the urinary bladder.