Medical Dictionary: U, V, W, and Y

ultrasound: A painless, noninvasive imaging method that uses high-frequency sound waves to locate and measure solid tumors.

Underwriters Laboratories (UL): An independent, nonprofit organization that tests products and certifies them as safe.

unopposed estrogen: Estrogen taken without an accompanying progestogen.

unsaturated fats: Fatty acids in which some of the hydrogen atoms in each molecule have been replaced by double bonds; includes monounsaturated and polyunsaturated fats.

urea: A waste product of protein digestion and metabolism.

ureters: The two tubes that connect the kidneys to the bladder.

urethra: Tube leading from the bladder through which urine is excreted from the body.

urethral hypermobility: Movement of the urethra out of place when abdominal pressure increases, leading to stress incontinence.

urethritis: Inflammation of the urethra.

urgency: A type of incontinence in which a person feels a sudden and uncontrollable need to urinate or defecate.

urinary incontinence: The inability to control urine flow, resulting in involuntary discharge or leakage.

urinary tract: The part of your body that produces and excretes urine; consists of the kidneys, ureters, bladder, and urethra.

urticaria (hives): An itchy rash of usually short duration.

vacuum erection devices: Various manual or battery-operated pumps that a man can use to draw blood into the penis to create an erection.

vascular surgery: An operation to improve blood flow to the penis, either by repairing leaks in blood vessels or by rerouting arteries to bypass blockages.

vascular: Having to do with blood vessels and circulation.

vasculitis: Inflammation of blood vessels.

vasectomy: An operation that ties off or cuts the tubes through which sperm travel from the testicles to the urethra.

vasoconstrictors: Substances that constrict blood vessels.

vasodilators: Substances that widen blood vessels.

vasospasm: A frequent complication following a hemorrhagic stroke in which a blood vessel contracts uncontrollably.

venous leak: A condition in which, during an erection, blood seeps out of the penis rather than remaining trapped within it.

vertebra: One of the cylindrical bones that form the spine (plural: vertebrae).

vertebrae: The 22 bones that form the spine.

vertebral artery: One of two blood vessels that run up the back of the neck and join at the base of the skull to form the basilar artery.

vertebroplasty: A minimally invasive procedure to stabilize compressed vertebrae and alleviate pain. A needle is inserted into the compressed portion of a vertebra and surgical cement is injected into it.

very low-calorie diet: A weight-loss diet that allows 800 or fewer calories per day (usually followed under medical supervision).

very-low-density lipoprotein (VLDL): A lipoprotein that transports triglyceride manufactured in the liver to fat tissue in the body; eventually becomes low-density lipoprotein (LDL) after the triglyceride has been removed.

vestibular system: The balance organs, located in the labyrinth in the inner ear.

visual acuity: The ability to focus and see things clearly, which is measured in a standard eye exam. Problems in visual acuity can usually be corrected with eyeglasses.

visual field: The scope of what the eye sees; includes central and peripheral vision.

visualized laser-assisted prostatectomy (VLAP): A technique used to treat BPH that allows the surgeon to view the prostate directly while it is being shrunk by a laser beam.

vitamin D: A hormone that plays a key role in ensuring the absorption of calcium from the intestines.

vitreous humor: The clear, gel-like substance that fills the space behind the lens and supports the shape of the rear portion of the eye.

volatile oils: Unstable components of a preparation that evaporate easily.

vulnerary: An agent that is believed to aid in wound healing.

warfarin: An anticoagulant drug that prevents blood clotting; people taking it must have regular blood tests to determine clotting time.

wart: An abnormal fibrous growth caused by a viral infection.

Weber test: A hearing test that uses a tuning fork to diagnose one-sided hearing loss.

whiplash: The popular term for muscle and ligament damage resulting from rapid and extreme extension and flexion of the neck. The term is also used for the accident causing the injury — most often a rear-end motor vehicle accident.

white-coat hypertension: Blood pressure elevations that occur in response to visits to a doctor’s office.

will: A legal document that relays wishes for disbursement of assets after a person’s death.

working memory: A type of short-term memory process that involves temporarily storing and manipulating information.

yohimbine: An extract of the bark of a West African tree sometimes used in treating erectile dysfunction. Yohimbine appears to increase blood flow to the penis and prevent blood from leaving it too quickly.