The kidneys: The major excretory organs for the elimination of nitrogenous wastes are the kidneys. A pair of bean-shaped organs - they are among the hardest working organs in the body.
The urine that is formed continuously in each kidney trickles out through the uterus.
The bladder is an expandable bag like structure, situated mainly in the pelvic cavity below the navel As it fills up, it expands upwards into the abdomen. The two ureters enter the bladder and travel for a few centimetres under the bladder wall.