53 Aging and Urinary System Homeostasis

Aging affects all body systems, but perhaps none undergoes as many age-related changes as the urinary system. Among the physical changes in urinary tract function that occur with aging are decreases in bladder capacity and bladder emptying, loss of sphincter muscle tone, and a reduced ability to delay voiding. In addition, age-related conditions such as stroke and Alzheimer’s disease can affect the micturition center in the brain. These are some of the reasons why urinary incontinence is so common in the elderly, affecting up to a third of older men and more than half of older women. Age-related changes in the kidneys include a decrease in organ size, decrease in renal blood flow, and impaired sodium conservation. The number of functional nephrons and the glomerular filtration rate (GFR) also decline with age. In fact, only about two percent of adults over age 70 have normal renal function. In about two thirds of the elderly, the GFR rate is less than 60 milliliters (2 ounces) per minute compared with the normal rate of 120 milliliters (4 ounces) per minute. This has important implications for the many drugs used to treat a variety of age-related conditions. Medication dosages must often be adjusted to compensate for the reduced renal clearance.

Common Dysfunctions of the Urinary System

The entire process of urination is known as micturition. A healthy, well functioning urinary system begins with urine being produced by the nephrons in the kidneys, continues via the process of peristalsis bringing the urine into the bladder, and ends with urine exiting through the urethra. However, the urinary system sometimes is compromised when it is permeated by bacteria.

Some Common ones and more well known ones include:

• Renal Ptosis
• Kidney Stones
• Pyelonephritis
• Kidney Failure