 A structure of the kidney. Renal pelvis. The expanded proximal end of the ureter and the renal pelvis receives urine from the calisees. Medulla. The middle portion of the internal structure of the kidney. Cortex. The outer portion of the internal structure of the kidney. Calyx. The cup-like extension of the renal pelvis that urine empties into. Adrenal gland. An endocrine gland that sits on top of the kidney. Renal capsule. The tough white fibrous membrane surrounding the kidney. Renal artery carries oxygenated blood to the kidney. Renal vein carries deoxygenated blood away from the kidney. Ureter. A tubular that drains urine from the kidney into the bladder. Abdominal aorta. The renal arteries that branch off from this large blood vessel. Inferior vena cava. The main blood vessel that drains blood from the lower part of the body. You have completed this learning activity on the structure of the kidney.