Final answer:
The outer surface of the kidney is covered by the renal fascia, a layer of fibrous connective tissue. This is the outermost of the three layers surrounding the kidney, with the other two being the perirenal fat capsule and the renal capsule.
Step-by-step explanation:
The layer of fibrous connective tissue covering the outer surface of the kidney is known as the renal fascia. This layer is crucial as it helps to anchor the kidneys within the abdominal cavity.
The kidneys are surrounded externally by three layers: the renal fascia is the outermost layer, followed by the perirenal fat capsule which provides cushioning and protection, and the innermost layer is the renal capsule that forms a clear, protective layer around the kidney itself.
Internally, the kidney is comprised of three major regions: the outer cortex, the middle medulla, and the inner renal pelvis. The outer cortex is granular due to the presence of nephrons, the functional units of the kidneys. The medulla contains the renal pyramids, and the renal pelvis leads into the ureters.
The kidneys are anchored to the posterior abdominal wall in a retroperitoneal position, meaning they are located behind the peritoneum, the lining of the abdominal cavity.