Organs of the Urinary System and Their Functions

The urinary system is one of the body's main eliminator of wastes. In addition, it helps to maintain normal levels of chemicals in you system.

Organs comprising the urinary system include the two kidneys, two ureters, the bladder, and the urethra. The following describes the different urinary organs and their functions.

Kidneys

The kidneys are bean-shaped organs located in the abdomen near the back, each of which lies on each side of the spinal column. They are partially protected by the lower ribs.

Within the kidneys are tiny filtering units called nephrons. Each kidney has about a million nephrons that aid in ridding the blood of wastes and excess water and chemicals. Sometimes, however, chemicals such as bicarbonate, potassium or hydrogen may be needed to be reabsorbed into the blood to maintain normal blood chemical composition.

Substances not needed by the body including excess water will then drain into the lower parts of the urinary system as urine.

Ureters

Each kidney, after reabsorbing or taking back needed substances, releases urine into a tube called the ureter. Each ureter measures about 10 to 12 inches long extending from the kidney to the bladder. This narrow passageway can be a potential area where a large kidney stone can lodge and cause excruciating pain.

Urine passes through the ureters and drain into the bladder.

Bladder

The urinary bladder, or simply bladder, is an elastic, balloon-shaped organ where urine is stored for some time until it is released when you urinate. The shape of the bladder changes: empty, the organ is collapsed and when it is filled with urine it is distended and becomes nearly spherical in shape.

As urine fills the bladder, the bladder wall is stretched, which in turn send signals to your central nervous system (brain and spinal cord) to inform you that it is time to drain the stored urine.

Urethra

The last part of the urinary system is the urethra where urine passes to exit the body during urination. The urethra in females is much shorter than in males. This may be the reason why women are at an increased risk of developing urinary tract infections than in males. Microorganisms that may be lurking in the opening of the female urethra have shorter distance to travel up the urinary where they can multiply and cause infection.

References:

Tortora, G. and Grabowski, S.: PRINCIPLES OF ANATOMY AND PHYSIOLOGY. 10th ed. John Wiley and Sons, Inc., 2003.

Seeley, R. et al: ESSENTIALS OF ANATOMY AND PHYSIOLOGY. 5th ed. McGraw - Hill, 2005.