Any of the membranous air-filled extensions of the lungs of birds, which increase the efficiency of gaseous exchange in the lungs [ http://www.thefreedictionary.com/air+sac http://en.wikipedia.org/wiki/Bird_anatomy#Respiratory_system ]

This is just here as a test because I lose it

Term information

latin term
sacci pneumatici

comment

Three distinct sets of organs perform respiration-the anterior air sacs (interclavicular, cervicals, and anterior thoracics), the lungs, and the posterior air sacs (posterior thoracics and abdominals). The posterior and anterior air sacs, typically nine, expand during inhalation. Air enters the bird via the trachea. Half of the inhaled air enters the posterior air sacs, the other half passes through the lungs and into the anterior air sacs. Air from the anterior air sacs empties directly into the trachea and out the bird's mouth or nares. The posterior air sacs empty their air into the lungs. Air passing through the lungs as the bird exhales is expelled via the trachea. Some taxonomic groups (Passeriformes) possess 7 air sacs, as the clavicular air sacs may interconnect or be fused with the cranial thoracic air sacs[WP]

definition

Any of the membranous air-filled extensions of the lungs of birds, which increase the efficiency of gaseous exchange in the lungs

depicted by

http://upload.wikimedia.org/wikipedia/commons/f/f2/BirdRespiration.svg

has exact synonym

sacci pneumatici

has related synonym

psotcranial air sac

id

UBERON:0009060