(i) Renal artery: It supplies oxygenated blood to the muscles of the kidney.(ii) Urethra: This tube allows urine to pass outside the body.(iii) Glomerulus: It acts as filter of blood to filter out the nitrogenous wastes from it.(iv) Tubular part of nephron: It helps in absorption and reabsorption of necessary salts and water content from the filtered blood. Thus they, maintain the blood osmolarity.