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.
Why Skin Gets Darker in Kidney Failure Patients. Many organs and systems are easily involved in Kidney Failure, so is skin. In addition to skin itching and dry skin, dark skin is another annoying skin changes for renal failure patients. Why skin gets darker on Kidney Failure patients?