Geriatric considerations - Urinary: Nursing

Geriatrics is the branch of medicine that deals with the physiology and psychology of aging, as well as the diagnosis and treatment of diseases affecting older clients. Now, aging affects various organ systems, one of which is the urinary system. All right, let's start by reviewing the physiology of the urinary system, which can be divided into the upper and lower urinary tracts. The upper urinary tract is made of the kidneys and the ureters, whereas the lower urinary tract includes the urinary bladder and the urethra. Each bean-shaped kidney sits just below and on each side of the diaphragm. They are about 12.5 centimeters long and weigh from 113 to 170 grams. They receive oxygenated blood through renal arteries, which arise from both sides of the abdominal aorta.

Now, let’s take a closer look at the inside of the kidney, which consists of an outer cortex and an inner medulla, both of which house the functional units of the kidneys, called nephrons. These tiny nephrons consist of a tuft of capillaries, called the glomerulus, surrounded by a double-membrane called the Bowman capsule. From the nephron, there extends a group of tubules, called the proximal convoluted tubule, loop of Henle, and distal convoluted tubule, which eventually drain urine into collecting tubules and ducts. From there urine drains into the ureters, which have smooth muscles in their walls that contract to push the urine towards the bladder. Urine then passes from the bladder to the urethra, where it exits the body.

Now, the kidneys also regulate the volume and composition of body fluids by controlling water, electrolytes, and the excretion of waste products and medications. The amount of blood that gets filtered through the kidneys each minute is called glomerular filtration rate, or GFR. Additionally, the kidneys help control blood pressure, regulate acid-base balance, activate vitamin D, and produce erythropoietin, which is a hormone that stimulates red blood cell production in the bone marrow. Hormones produced by other organs can also alter the function of the kidneys. These hormones include aldosterone, antidiuretic hormone, or ADH, and atrial natriuretic peptide, also known as ANP. Aldosterone is produced by the adrenal glands, and promotes reabsorption of water and sodium, in return for excretion of potassium.

On the other hand, ADH is a hormone released by the posterior pituitary gland. This hormone increases water reabsorption from the kidney tubules where it is returned back to the circulation. Finally, ANP is released from the atria of the heart, and it inhibits sodium excretion and increases the GFR. The effects of aging on the urinary system include changes in structure and function. With age, bladder capacity decreases, which can lead to nocturia and sleep disturbances. Although urinary incontinence is not a normal part of aging, an involuntary loss of urine can be caused by a weakened pelvic floor, which is a group of muscles and ligaments that support the bladder, uterus, and urethra; as well as instability of the detrusor muscle, which contracts during urination to help move the urine out of the bladder.