| Term | Definition |
| Retroperitoneal | Behind the peritoneum |
| Functions of the urinary system | Excretion of waste; regulation of blood composition; regulation of blood pH; regulation of blood volume; regulation of B.P - less water = lower blood pressure |
| Urinary system | Composed of 2 kidneys, 2 ureters, a urinary bladder, and a urethra |
| Hilus | Depression on the medial side of a kidney where blood vessels and nerves enter and exit |
| Renal fascia | Outermost layer of the kidney composed of dense irregular tissue; anchors kidney to the back of the body wall |
| Adipose capsule | Middle fatty layer surrounding the kidney; provides protection |
| Renal capsule | Innermost layer of surround tissue of the kidney; thinnest layer; helps prevent the spread of infection to the kidney; contains WBC's to fight infections |
| Afferent arteriole | A group of blood vessels that supply the nephrons of the kidney and later diverge into the capillaries of the glomerulus; they play an important role in the regulation of blood pressure |
| Glomerulus | A capillary tuft surrounded by Bowman's capsule in nephrons of the kidney; receives its blood supply from an afferent arteriole of renal circulation; unlike most other capillary beds, it drains into an efferent arteriole rather than a venule |
| Efferent arteriole | Blood vessels that form from a convergence of the capillaries of the glomerulus; splits into two capillary beds: the vasa recta and peritubular capillaries, which reunite to form veins |
| Vasa recta | Long loop-shaped capillaries that extend from some efferent aterioles to supply tubular portions of the nephron in the renal medulla |
| Peritubular capillaires | Capillaries that form from efferent arterioles that surround tubular parts of the nephron in the renal cortex |