Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «R»:
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Raynaud's phenomenon
Raynaud's phenomenon: A condition resulting in
discoloration of fingers and/or toes when a person is exposed to
changes in temperature (cold or hot) or emotional events.
The skin discoloration occurs because an abnormal spasm of
the blood vessels causes a diminished blood supply. Initially, the
d...
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RBC
RBC: Short for red blood cells, the cells that carry oxygen and carbon dioxide through the blood. This rather remarkable feat is thanks to hemoglobin, the pigment that makes red cells (and blood) look red. The red blood cells are also known as red corpuscles or erythrocytes (literally, red hollow v...
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RCT
RCT: Randomized controlled trial....
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RDA
RDA: Abbreviation for the Recommended Dietary Allowance. Or, popularly, the Recommended Daily Allowance....
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RDIs (Reference Daily Intakes)
RDIs (Reference Daily Intakes): A set of dietary
references based on the Recommended Dietary Allowances for
essential vitamins and minerals and, in selected groups,
protein. The name "RDI" replaces the term "U.S. RDA."...
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RDS (respiratory distress syndrome)
RDS (respiratory distress syndrome): Formerly known as hyaline membrane disease, a syndrome of respiratory difficulty in newborn infants caused by a deficiency of a molecule called surfactant.
RDS almost always occurs in newborns born before 37 weeks of gestation. The more premature the baby is, th...
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Re-uptake
Re-uptake: See: Reuptake....
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Reabsorption
Reabsorption: Absorbing again. For example, the kidney
selectively reabsorbs substances such as glucose, proteins, and sodium which it had
already secreted into the renal tubules. These reabsorbed substances return to the blood. ...
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Reactant, acute phase
Reactant, acute phase: See: Acute-phase protein....
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Reaction kinetics
Reaction kinetics: Kinetics (with an "s" at the
end) refers to the rate of change in a biochemical (or
other) reaction, the study of reaction rates. Kinetics is a
noun. It is distinct from "kinetic" (an adjective) meaning
with movement. The opposite of kinetic is akinetic which
means without mo...
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Reaction, allergic
Reaction, allergic: A reaction that occurs when the
immune system attacks a usually harmless substance (an allergen) that gains access to the
body. The immune system calls upon a protective substance called immunoglobulin E (IgE) to
fight these invading allergic substances (allergens). Even though e...
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Reaction, chemical
Reaction, chemical:
A process in which one substance is transformed into another. Thousands of different types of chemical reactions occur in the body and are essential to its structure and function....
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Reaction, desmoplastic
Reaction, desmoplastic: This term refers to the growth of fibrous or connective tissue. Some tumors elicit a desmoplastic reaction, the pervasive growth of dense fibrous tissue around the tumor. Scar tissue (adhesion) within the abdomen after abdominal surgery is another type of desmoplastic reactio...
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Reaction, hibernation
Reaction, hibernation: See: SAD....
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Reaction, polymerase chain
Reaction, polymerase chain: See: PCR....
