Ulcer, duodenal: An ulcer (a hole in the lining) of the duodenum (the first portion of the small intestine). Ulcer formation is related to H. pyloridus bacteria in the stomach, anti-inflammatory medications, and smoking cigarettes. Ulcer pain may not correlate with the presence or severity of ulceration. Diagnosis is made with barium x-ray or endoscopy. Complications of ulcers include bleeding and perforation. Treatment involves antibiotics to eradicate H. pyloridus, eliminating risk factors, and preventing complications.

Ulcer, esophageal: A hole in the lining of the esophagus (tube-like organ leading from the throat to the stomach) corroded by the acidic digestive juices secreted by the stomach cells. Ulcer formation is related to H. pyloridus bacteria in the stomach, anti-inflammatory medications, and smoking cigarettes. Ulcer pain may not correlate with the presence or severity of ulceration. Diagnosis is made with barium x-ray or endoscopy. Complications of ulcers include bleeding and perforation. Treatment involves antibiotics to eradicate H. pyloridus, eliminating risk factors, and preventing complications.

Ulcer, gastric: A hole in the lining of the stomach corroded by the acidic digestive juices which are secreted by the stomach cells. Ulcer formation is related to H. pyloridus bacteria in the stomach, anti-inflammatory medications, and smoking cigarettes. Ulcer pain may not correlate with the presence or severity of ulceration. Diagnosis is made with barium x-ray or endoscopy. Complications of ulcers include bleeding, perforation, and blockage of the stomach (gastric obstruction).

Ulcer, peptic: A peptic ulcer is a hole in the lining of the stomach, duodenum, or esophagus. A peptic ulcer of the stomach is called a gastric ulcer, an ulcer of the duodenum is a duodenal ulcer, and a peptic ulcer of the esophagus is an esophageal ulcer. A peptic ulcer occurs when the lining of these organs is corroded by the acidic digestive juices which are secreted by the stomach cells. Peptic ulcer disease is common, affecting millions of Americans yearly. The medical cost of treating peptic ulcer and its complications runs in the billions of dollars annually in the U.S. Recent medical advances have increased our understanding of ulcer formation. Improved and expanded treatment options are now available.

Ultrasound/Ultrasonography: A test in which high-frequency sound waves (ultrasound) are bounced off tissues and the echoes are converted into a picture (sonogram).

Ultraviolet radiation: Invisible rays that are part of the energy that comes from the sun. Ultraviolet radiation can burn the skin and cause skin cancer. It is made up of two types of rays, UVA and UVB. UVB rays are more likely than UVA rays to cause sunburn, but UVA rays pass further into the skin. Scientists have long thought that UVB radiation can cause melamona and other types of skin cancer. They now think that UVA radiation also may add to skin damage that can lead to cancer. For this reason, skin specialists recommend that people use sunscreens that block both kinds of radiation.

Umbilicus: The navel or belly button.

Unicornuate: Having one horn or being shaped-shaped. The uterus is normally unicornuate.

Unique identifier reporting: In public health, a system that uses information such as the person’s birth date and part of their identification number (in the U.S., the social security number) to create a unique code that is reported instead of a name. It is an alternative to named reporting that provides some of the surveillance benefits of reporting by name, such as the elimination of duplicate reports, while reducing privacy concerns by avoiding use of a person’s name. For example, HIV testing in Maryland and Texas is done with unique identifier reporting.

Upper GI series: A series of x-rays of the esophagus, stomach, and small intestine (upper gastrointestinal, or GI, tract) that are taken after the patient drinks a barium solution. (Barium is a white, chalky substance that outlines the organs on the x-ray.)

Urban typhus of Malayia: Murine typhus, an acute infectious disease with fever, headache, and rash, all quite similar to, but milder than, epidemic typhus, caused by a related microoganism, Rickettsia typhi (mooseri), transmitted to humans by rat fleas (Xenopsylla cheopis). The animal reservoir includes rats, mice and other rodents. Murine typhus occurs sporadically worldwide but is more prevalent in congested rat-infested urban areas. Also known as endemic typhus, andrat-flea typhus.

Urea: A substance containing nitrogen that is normally cleared from the blood into the urine by the kidney. Diseases that compromise the function of the kidney often lead to increased blood levels of urea, measured by the blood urea nitrogen (BUN) test.

Urea breath test (UBT): A test for the presence of the bacteria Helicobacter pylori that causes inflammation and ulcers in the stomach. The breath test is based on the ability of H. pylori to break down urea. Ten minutes after swallowing a capsule containing urea with labeled carbon, a breath sample is collected to detect labeled carbon in the exhaled breath. A positive test indicates active infection. The test turns negative after eradication of the bacteria from the stomach with antibiotics.

Urethra: Transport tube leading from the bladder to discharge urine outside the body. In males the urethra travels through the penis.

Urethritis: Inflammation of the urethra. The urethra is the transport tube leading from the bladder to discharge urine outside the body.

Ureters: The tubes that carry urine from each kidney to the bladder.

Uric acid: A breakdown product of purines that are part of many foods. In gout, there are frequently, but not always, elevated levels of uric acid in the blood (hyperuricemia). However, only a small portion of those with hyperuricemia will develop gout.

Urinalysis: A test that determines the content of the urine.

Urinary: Having to do with the kidneys, ureters, and bladder. The urinary system represents the functional and anatomic aspects of the kidneys, ureters, and bladder.

Urinary tract: The organs of the body that produce and discharge urine. These include the kidneys, ureters, bladder, and urethra.

Urinary tract infection (UTI): Infection of the kidney, ureter, bladder, or urethra. Not everyone with a UTI has symptoms. Common symptoms include a frequent urge to urinate and a painful, burning when urinating. More females than males have UTIs. Underlying conditions that impair the normal urinary flow can lead to complicated UTIs.

Urine: Liquid waste.

Urologist: A doctor who specializes in diseases of the urinary organs in females and the urinary and sex organs in males.

Uterine tubes: See Fallopian tubes.

Uterus: A small, pear-shaped muscular organ in the pelvis of females where the unborn child develops until birth. Also called the womb.

Urticaria: Hives. Raised, itching areas of skin, often a sign of an allergic reaction. Also called "welts" or "nettle rash."

UTI: Urinary tract infection. (Not to be confused with URI: upper respiratory infection).

Uvula: The prominent anatomic structure dangling downward visibly at the back of the mouth (pharynx).