Phagocytosis.

Consumption of foreign particles (e.g., bacteria) by cells that surround the particle and then ingest it.

Plenum.

A space filled with matter (not a vacuum); an enclosed volume of gas under greater pressure than that surrounding the container.

Pneumoconiosis.

A condition characterized by mineral dust deposits in the lungs as a result of occupational or environmental exposure.

Pneumonitis.

Inflammation of the lungs.

Prevalence rate.

The ratio of the number of morbid cases to the number of people at risk at a specific time and place.

R

Reagent.

Any substance capable of reacting with another, particularly if the reaction produces a change of physical properties whereby the second substance may be detected or measured. For example, dimethylglyoxime is a reagent for nickel, iron, bismuth, etc. The reagent is called selective if it indicates the presence of a small number of compounds or ions, and specific (or characteristic) if it only gives an indication with a single substance.

Reservoir.

Any source of infection; a space, container, or depot in which something accumulates or is kept in reserve.

Resistance.

The native or acquired ability of an organism to maintain its immunity to ward off disease.

Rhinitis.

Inflammation of the lining of the nose.

Rhinoconjunctivitis.

A condition that consists of a combination of rhinitis and conjunctivitis.

Rhinomanometry.

The measurement of airflow and variations in air pressure within the nose. The resistance to respiration offered by the nasal soft tissues may be calculated from the results of the measurement.

S

Saprophytic.

Obtaining food by absorbing dissolved organic material.

Sensitization.

The process by which an immune response is stimulated on first being exposed to an antigen, with the consequence of preparing the body's immune system for a stronger response upon reexposure to the same antigen, as in a hypersensitivity reaction.

Serology.

The study of serum, the watery liquid that separates from coagulated blood.

Serum.

The clear yellowish fluid obtained when whole blood is separated into its solid and liquid components.

Silicosis.

A condition of lung fibrosis that is brought about by prolonged inhalation of silica dust.

Skin tests.

Tests for an allergy or infectious disease, performed by a patch test, scratch test, or an intracutaneous injection of an allergen or extract of the disease-causing organism.



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