4. The urinary tract
This diagram shows the urinary tract in men and women
The urinary tract is made up of two kidneys and their ureters (tubes linking the kidneys with the bladder), the bladder and the urethra. The kidneys are bean-shaped organs that filter waste products from the blood and convert them into urine. The ureters are hollow tubes that transport urine from the kidneys to the bladder. The bladder is a muscular sac that has two functions: to store urine and to pass urine from the body. The urethra is the tube from the bladder that allows the passing of urine. It is much shorter in women than in men.