Components of urinary system: all of these structures are retroperitoneal, behind the peritoneum. 11-12th ribs partially protect kidneys: attached to posterior peritoneal wall, right kidney slightly lower than left due to liver on right kidney, associated adrenal gland, hilum, where blood vessels go through. What would happen if there was a blow to posterior body: kidneys are relatively superficial in posterior abdominal wall not a lot of protection. Trauma or force to posterior abdominal wall would interfere with kidney function. Lead to buildup of waste and salt ions: results in toxic environment and other health issues. Kidneys: support: septum that attaches kidney to adrenal gland on top (red arrow, different blood supply to each kidney. 3 layers that support and protect the kidney: Innermost layer attached to kidney surface: protects kidney, also acts as barrier against potential infections of peritoneum. Adipose capsule: provides a cushioning and protective layer of fatty tissue, anterior adipose capsule much thinner than posterior adipose.