A projecting ridge or fin on the bottom of the hull of a boat or ship that improves directional control and is often weighted for added stability. 2. The principal structural member of an aircraft, resembling a ship's keel in shape and function.
The outer, reddish region, next to the capsule, is the renal cortex. This surrounds a darker reddish-brown region called the renal medulla. The renal medulla consists of a series of renal pyramids, which appear striated because they contain straight tubular structures and blood vessels.
If you were to cut a kidney in half, you would see the following parts: Renal capsule - a thin, outer membrane that helps protect the kidney. Cortex - a lightly colored outer region. Medulla - a darker, reddish-brown, inner region. Renal pelvis - a flat, funnel-shaped cavity that collects the urine into the ureters.