In histology, the urinary system refers to the microscopic study of the kidneys, ureters, bladder, and urethra. It focuses on the specialized structures within the kidney (nephrons, glomeruli, tubules) responsible for filtering blood and producing urine, as well as the layered structure of the ureters, bladder, and urethra that facilitate urine transport and storage. Histological examination reveals the intricate cellular organization that enables waste removal, fluid balance, and electrolyte regulation.