Anatomy Urinary Tract

The human body requires nutrients to function. Nutrients from food and drink provide the energy it needs to perform external tasks (such as walking) and internal tasks (such as keeping the blood flowing throughout the body). Nutrients also provide the energy needed for the body to heal itself from cuts, scrapes, bruises, infections, and other ailments. Nutrients are the body ‘s fuel.

The process of extracting nutrients from the foods we eat involves complicated biochemical reactions that occur in the body. As these reactions take place, certain “left-overs ” remain after the body has taken what it needs from food. These “extras ” are called waste products and the body has a complicated set of systems for eliminating them.

The urinary tract system, the lungs, the skin, and the intestines all work toward eliminating the body ‘s waste products. They are each working constantly to ensure that the body has enough water and that its internal chemicals remain balanced. The urinary tract system eliminates through urine, the lungs through the breathing process, the skin through sweat, and the intestines through digestion and bowel movements. Without these elimination systems, the body would develop fatal infections and toxins.

Human Urinary Tract System

Urinary System Function

The urinary tract system extracts a specific type of waste called urea from the bloodstream. The body actually makes urea waste when it processes foods that contain protein. Once produced, urea moves through the bloodstream to the kidneys, which are located just below the rib cage and are shaped like fist-sized kidney beans.

If the kidneys are not functioning correctly, as with renal failure, urea is not removed well or at all and it builds up in the system causing nausea/vomiting, weakness, loss of appetite, and mental confusion. With normal kidneys, as the urea passes through it joins with water and other waste products to form urine.

Other Functions

In addition to removing urea from the blood stream the kidneys also play an important role in the production of three substances necessary for body processes:

  • erythropoietin, a hormone involved in red blood cell production
  • rennin, a hormone that helps regulate blood pressure
  • activated form of vitamin D which helps maintain bone-density.

The urine then travels into the ureters, 8 to 10-inch tubes that lead to the bladder. About every 10 to 15 seconds, the ureters release a small amount of urine into the bladder. Depending upon the individual and the condition of his or her urinary tract system, it takes between two and five hours for the bladder to become uncomfortably full. When full, nerves in the bladder send a signal to the brain that the bladder needs to be emptied. At the appropriate time, the brain sends a signal back down to the bladder to relax its associated muscles and allow the urine to pass into the urethra, the tube that transfers urine from the bladder out of the body.

In men, the urethra is about 8 to 9 inches long and stretches from the bladder to the very end of the penis, passing through the penis on its way. In women, the urethra is much shorter, less than 3 inches long. The female urethra starts at the bladder and continues to the opening of the vagina.

Urinary Tract Problems

Problems and infections related to the urinary tract system range from common to serious and even fatal. Certain conditions, such as childbirth, menopause, pelvic surgery, diabetes, decreased mobility, and diuretic medication may put individuals at risk for urinary system infections or incontinence. One of the greatest risk factors, however, is simple aging. As the human body ages, the kidneys, ureters, urethra, and bladder become less effective. This weakness often results in urine that sits in the bladder without being excreted. The sitting urine fosters infections that may even spread to neighboring internal systems.

Symptoms of urinary tract infections and other urinary tract ailments include passing too little urine while enduring swelling at the ankles and feet (kidney disease and failure); the frequent urge to urinate while passing only small amounts of urine or painful urination (bladder or urethral infection); and blood in the urine (kidney stones, malignancy).

Resources

Howes, D.S. (updated 2002). Urinary tract infection, female. Retrieved May 23, 2004, from www.emedicine.com/emerg/topic626.htm.

Koop, E.C. The urinary system.Dr. Koop ‘s Self-Care Advisor. Time Life Medical. First Edition. 1996.

National Kidney and Urologic Diseases Clearinghouse. (2003, November).Urinary tract infections in adults [NIH Pub. No 04-2097].

Rajaratnam, G. (nd). Urinary anatomy. Retrieved May 23, 2004, from www.drrajmd.com/ut/urinaryanatomy.htm.

Virginia Urology. (nd). Urinary tract infections (UTI) in men. Retrieved May 23, 2004, from www.uro.com/utim.htm.