Urology is the branch of medicine concerned with the urinary tract in both genders, and with the genital tract or reproductive system in the male. Urogenital is a word that refers to the urinary and genital organs.
The medical specialty of Obstetrics and Gynecology specializes in the reproduction (genital) system of females. Nephrology is the medical specialty concerned with the kidneys.
According to the National Kidney Foundation, kidney and urologic diseases affect more than 20 million people. More than 70,000 US adults die each year from kidney failure. The number of people affected by these diseases is expected to grow as the populations of older adults and racial and ethnic minorities, groups disproportionately affected by the diseases, increase.The most serious and debilitating of kidney and urinary tract diseases includes end-stage renal disease (ESRD); kidney stone disease; urinary incontinence; benign prostatic hyperplasia (BPH); interstitial cystitis; urinary tract infection; and polycystic kidney disease.
Other diseases also have a tremendous impact on the disability and death associated with kidney and urologic diseases, including diabetes and hypertension.
Anatomy of the Kidneys and Urinary System
How do the kidneys and urinary system work?
The body takes nutrients from food and converts them to energy. After the body has taken the food that it needs, waste products are left behind in the bowel and in the blood.
The kidney and urinary system keeps the chemicals and water in balance by removing a type of waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.
Kidney and Urinary system parts and their functions :
- Two kidneys - a pair of purplish-brown organs located below the ribs toward the middle of the back. Their function is to remove liquid waste from the blood in the form of urine; keep a stable balance of salts and other substances in the blood; and produce erythropoietin, a hormone that aids the formation of red blood cells.
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.
Two ureters - narrow tubes that carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.
- Bladder - a triangle-shaped, hollow organ located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours.
- Two sphincter muscles - circular muscles that help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder.
- Nerves in the bladder - alert a person when it is time to urinate, or empty the bladder.
- Urethra - the tube that allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.
Facts about urine
- Adults pass about a quart and a half of urine each day, depending on the fluids and foods consumed.
- The volume of urine formed at night is about half that formed in the daytime.
- Normal urine is sterile. It contains fluids, salts and waste products, but it is free of bacteria, viruses and fungi.
There are many disorders of the kidney that require clinical care by a physician or other healthcare professional. Listed in the directory below are some of the conditions, for which we have provided a brief overview.
If you cannot find the condition in which you are interested, please visit the Kidney and Urinary Disorders Online Resources page in this Web site for an Internet/World Wide Web address that may contain additional information on that topic.