The Cellular and Acellular Components of the Urinary Sediment

Urine is a toxic substance produced by the kidney and eliminated from the body by a series of hollow organs of the lower urinary tract, consisting of renal pelves, ureters, bladder, and urethra. Each organ of the lower urinary tract is composed of three layers of tissues: the epithelium, lining the lumen, resting on a layer of connective tissue or the lamina propria and muscular layers that vary in thickness from organ to organ. These organs are separated from the abdominal cavity by a serosa composed of mesothelial cells, capillary vessels, and loose connective tissue.