Word Of The Day

Dorland's Word of the Day is a great way to broaden your knowledge of medical terminology. With a new and interesting term brought to you from the 32nd edition of Dorland's Illustrated Medical Dictionary each day, it's an easy and fun way to increase your medical vocabulary!

You can view a new word on this website each day.

Today's Word

follicle recruitment

the process by which only some primordial follicles in the ovary begin growing in a given menstrual cycle.

Word of the Day Archive

homing receptor

a cell-surface molecule that directs tissue- or organ-specific attachment of that cell; specifically, one of the surface proteins of lymphocytes that mediate their attachment to a particular type of vascular endothelium.

Mazzotti reaction

the set of adverse reactions, which may be severe or rarely life-threatening, that accompany the administration of diethylcarbamazine in onchocerciasis, most commonly an intensely pruritic rash, but sometimes also systemic manifestations such as fever, malaise, lymph node swelling, eosinophilia, arthralgias, tachycardia, and hypotension; if numerous microfilariae are present in the eyes, blindness may occur.

late phase reaction

an IgE-mediated immune reaction occurring 5 to 8 hours after exposure to antigen, after the wheal and flare reactions of immediate hypersensitivity have diminished; it is characterized by inflammation, with accumulation of neutrophils, basophils, eosinophils, and CD4+ T lymphocytes, pruritus, and minor cellular infiltration. Prostaglandins are not formed. Inflammation subsides after reaching a maximum around 24 hours after exposure.

hemianopic pupillary reaction

reaction in certain cases of hemianopia in which the stimulus of light thrown upon one side of the retina causes the iris to contract, while light thrown on the other side arouses no response. Called also Wernicke's reaction.

delayed hypersensitivity reaction

a reaction of cell-mediated immunity, named in contrast to immediate hypersensitivity reactions because its onset is 24 to 72 hours after the antigenic challenge; the term is usually used to denote the subset of type IV hypersensitivity reactions (Gell and Coombs classification) involving cytokine release and macrophage activation, as opposed to direct cytolysis, but can be used more broadly, even sometimes being used synonymously with the term type IV (T-cell mediated) hypersensitivity reaction. The classic delayed hypersensitivity reaction is the tuberculin reaction observed in skin testing.

anaphylactoid reaction

a reaction resembling generalized anaphylaxis but not caused by IgE-mediated allergic reaction, instead being due to nonimmunologic degranulation of mast cells with release of the pharmacological mediators involved in anaphylaxis. Called also anaphylactoid shock.

protein catabolic rate (PCR)

a calculation derived by multiplying 6.25 times the amount of nitrogen in grams excreted in the urine over a given time period; this represents the amount of protein catabolized by the body in excess of protein synthesis. In a healthy steady state of nitrogen balance it approximates the amount of protein in the diet.