Page 274 - Industrial Ventilation Design Guidebook

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GLOSSARY

Bloodstream: Volume of blood circulating through the heart, arteries, capil-
laries, and veins or within a certain anatomical region.
Body core temperature: Hypothetical "average" internal organ temperature,
typically referenced to either right atrial or brain temperature. A reference
value of 37 °C is generally used under normal environmental conditions,
Breathing frequency: Number of breaths per minute.
Bronchioles: Noncartilaginous, smaller, more distal subdivision of tracheo-
bronchial tree. Walls consist of smooth muscle and elastic fibers.
Buccal: Pertaining to the lateral inner surface of the oral cavity (cheek).
Bulk transport: Transport of relatively large quantities of material by forced
convection.
Capacitance vessels: Larger venules and veins forming a large-volume, low-
pressure system of blood vessels.
Carbon dioxide production: Rate at which the pulmonary bloodstream trans-
ports carbon dioxide, produced by metabolic processes, to the pulmonary
airstream.
Cartilaginous: Consisting of cartilage.
Catabolism: Destructive metabolism; breakdown of complex chemical com-
pounds into simpler ones.
Chemical neutralization: Chemical reaction that converts acids or bases to
nonreactive salts.
Cilia: Hair-like motile extensions of a cell wall. Airway cells use cilia to pro-
pel mucus gel toward the epiglottis.
Ciliary beat frequency: Rate at which cilia travel through both the power
and recovery phases of the ciliary beat cycle.
Ciliary beat power phase: Interval during which forward ciliary movement
propels mucus gel toward the epiglottis.
Ciliary beat recovery phase: Interval during which cilia bends and returns
to initial position before power stroke. Minimal mucus gel retrograde
movement is thought to occur.
Clearance: Removal of a substance from the airway.
Concentration gradient: Difference in concentration measured between two
points.
Concha: One of three bony projections in the nasal turbinate region.
Conducting airways: Portion of respiratory tract through which air is trans-
ported but in which oxygen and carbon dioxide are not exchanged with
the bloodstream.
Dead space: The portion of each breath that does not participate in gas ex-
change. Anatomical dead space is the volume of the conducting airways;
physiological dead space also includes the contribution of pulmonary air-
ways that are well-ventilated but poorly perfused.
Dental plaque: Mass of microorganisms attached to a tooth surface.
Deoxygenated blood: Blood containing hemoglobin with oxygen levels be-
low fully saturated.
Diaphragm: Large abdominal muscle that varies pleural pressure resulting
in movement of air through the respiratory tract.
Diffusion-limited: A chemical or physical process that depends upon the
supply of material via diffusion.