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.
At the middle of this indentation a tube called the ureter leaves the kidney, and nerves, and blood and lymph vessels also lead in and out of the kidney. Each kidney is covered by three layers made out of fat or connective tissue, the so-called kidney capsule (or renal capsule).These layers give the kidney extra stability, protect it from external harm and anchor it in the surrounding tissue.The kidney is surrounded by a thin outer renal cortex.t the middle of this indentation a tube called the ureter leaves the kidney, and nerves, and blood and lymph vessels also lead in and out of the kidney. Each kidney is covered by three layers made out of fat or connective tissue, the so-called kidney capsule (or renal capsule).