[Solved] Explain what may contribute to the disparities found in the United States with regard to AIDS. Ideal Hilum: A depression or fissure where structures such as blood vessels and nerves enter an organ. Urine Collects: Describes the process in the kidneys where the urine is accumulated in the renal pelvis before being passed into the bladder. Microscopic Structure: The detailed architecture of an object that is too small to be seen with the naked eye, often requiring a microscope for examination. Plane of Section: A specific direction through a body or structure to expose a surface for study.