Urinary System : The Classical World

Introduction

The urinary system involves the organs and structures that deal with the capture and elimination of urine from the body. Urine is composed of water (95%) and waste products from the liver (urea) and of the muscle metabolism (creatine). The chief organs, the two kidneys, filter the blood and send the urine to a storage area, the bladder, through two ureters, and then from the bladder through a single channel, the urethra, to the opening to the outside of the body, the urethral meatus. Since in males the urethra also transports semen within the penis, the specialist in the urinary system, the urologist, also deals with the male reproductive system.

The nephron is the microscopic functional unit of the kidney containing cells and capillaries, which form the urine and carry it by means of a system of chalice-like microscopic ducts (calices) to the basin-like pelvis of the ureter, before its transportation to the bladder.