The system through which nitrogenous wastes are excreted from the body is called the excretory system. Different parts of excretory system are-
1. Kidney: Kidney looks like a bean seed. Its outer side is convex and inner side is concave. Below the ribcage in the lumbar region of the abdominal cavity are two kidneys on either side of the spine. The left kidney is slightly larger than the right kidney. The upper edge of the kidney lies below the 12th thoracic vertebra and is protected by the 11th and 12th vertebrae. The lower edge of the kidney lies above the third lumbar vertebra. The left kidney lies slightly above the liver and the right kidney slightly below.
2. Ureter: The tube that originates from the pelvis and opens into the urinary bladder is called the ureter. Its length is about 25-30 cm. It carries urine from the kidneys to the bladder.3. Urinary bladder: Urinary bladder is a triangular sac. Its wall is thin, elastic and composed of involuntary muscles called detrusors. It acts as a urinary reservoir. The bladder can hold 700-750 ml of urine. However, only when 280-320 ml of urine accumulates, the urge to urinate arises. Patients with hyperuricosuria develop stones in the urinary bladder.
4. Urethra: The narrow tube behind the urinary bladder is called the urethra. The length of the urethra is 18-20 cm in males and 3.5-4.0 cm in females. Urine is released through it.