Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «U»:
Umbilical cord: The cord that connects the
developing embryo or fetus with the placenta and through which run the umbilical arteries and vein. The matrix (the substance) of the umbilical cord is
known as Wharton's jelly and is a rich source of stem cells. At birth the umbilical cord measures about ...
Umbilicus: The vestige left behind on a newborn's
belly when the umbilical cord is cut. Also called the navel or belly
UMP: Uridine monophosphate....
Unassisted childbirth: Birth of a baby without the assistance of an obstetrician, midwife, or other health professional. This may be by accident or by design. Unassisted childbirth is fraught with risks since about a fifth of apparently normal pregnancies develop unexpected complications during labo...
Uncertainty: You may be uncertain why "uncertainty" deserves a place in a medical dictionary but some would say that uncertainty is a key element in medicine.
"The core predicament of medicine -- the thing that makes being a patient so wrenching, being a doctor so difficult and being a part of a so...
Unconscious: 1. Interruption of awareness of
oneself and one's surroundings, lack of the ability to
notice or respond to stimuli in the environment. A person
may become unconscious due to oxygen deprivation, shock,
central nervous system depressants such as alcohol and
drugs, or injury.
2. In p...
Unconsciousness, temporary: A partial or complete loss of
consciousness with interruption of awareness of oneself and ones
surroundings. When the loss of consciousness is
temporary and there is spontaneous recovery, it is referred to as
syncope or, in nonmedical quarters, fainting. Syncope acco...
Under the weather
Under the weather: Colloquial expression for sick or ill as, for example, to be under the weather with the flu. The phrase "under the weather" came from British sailing ships. When a sailor became ill he was confined below deck out of the weather, so it was said that he was under the weather....
Underload syndrome: Literally being "bored sick." Lack of stimulation in life (such as with an extremely dull job) can result in depression and health problems including headaches, fatigue and recurrent infection....
Underventilation: See: Hypoventilation....
Underwater weighing: A method for determining the lean body mass. This method weighs a person underwater and then calculates the lean body mass (muscle) and body fat. This method is one of the more accurate ones. However, it is generally done in special research facilities, and the equipment is cost...
Undifferentiated cancer: A cancer in which the cells are very immature and "primitive" and do not look like cells in the tissue from it arose. As a rule, an undifferentiated cancer is more malignant than a cancer of that type which is well differentiated. Undifferentiated cells are said to be anapla...
Undulant fever: An infectious disease due to the bacteria Brucella that characteristically causes rising and falling fevers, sweats, malaise, weakness, anorexia, headache, myalgia (muscle pain) and back pain.
The disease is called undulant fever because the fever is typically undulant, rising and...
Undulatant: Having a wavy border or form. Also, rising and falling like a wave. For example, the border of a wound may be undulant, as may the edge of a rash. And sound waves may also be undulant.
The word "undulant" comes from the Latin "undula" which is the diminutive of "unda" meaning wave. So "...
Undulate: To have a wavy border or form. Also, to rise and fall like a wave. For example, the border of a wound may undulate, as may the edge of a rash. And sound waves may undulate.
The word "undulate" comes from the Latin "undula" which is the diminutive of "unda" meaning wave. So "undula" is a l...