U

• Ulcers - skin lesions of the skin or mucous membrane it results from inflammation, it destroys cells in the area and is accompanied by the formation of pus

• Ulna - the bone of the forearm on the side opposite to the thumb

• Ultraviolet cabinet - a unit used to keep clean previously sterilised equipment, Ultraviolet rays are used to sanitise the surface of the objects placed in the cabinet

• Ultraviolet light - sunlight travelling through space as waves, a form of radiation not visible to the human eye, it cannot be felt, however it does have the ability to cause harm to living cells (sunburn).

• Ultrasound - sound waves of a very high frequency (above 20,000HzUltraviolet rays - invisible short-wavelength radiation beyond the violet end of the visible spectrum

• Urea - a water soluble compound that is the end product of protein metabolism, it is the chief component of urine.

• Urticaria - an itchy rash charaterised by, pale or reddened, irregular elevated patches and severe itching, it results from the release of histamine into the skin in response to an allergic reaction. It is also known as nettle rash or hives.