Which structure directly connects the kidneys to the bladder?

The structure that directly connects the kidneys to the bladder is the ureter. Each kidney has a ureter that transports urine, which is produced in the kidneys, to the bladder for storage. The ureters are muscular tubes that facilitate the movement of urine through peristaltic waves, effectively moving the liquid from the renal pelvis to the bladder.

Understanding the roles of other structures is also important. The urethra, for instance, is involved in the excretion of urine from the bladder to the outside of the body, rather than connecting the kidneys and bladder. The aorta is the major artery that carries oxygenated blood from the heart to the rest of the body, and the renal artery branches off the aorta specifically to supply blood to the kidneys but does not connect them directly to the bladder. This context helps clarify why the ureter is the correct structure in this scenario.