air sac

air sac

n.

A tiny, thin-walled, capillary-rich sac in the lungs where the exchange of oxygen and carbon dioxide takes place. Also called alveolar sac.

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air sac,

a small, terminal cavity in the lung, consisting of the alveoli connected to one terminal bronchiole.

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sac

a pouch; a baglike organ or structure. See also conjunctival sac.

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air sac

1. alveolar sac.

2. one of the large air-filled diverticula of the respiratory system of birds. See also air sacs.

allantoic sac

see allantois.

alveolar s's

the spaces into which the alveolar ducts open distally, and with which the alveoli communicate.

anal sac

see anal sacs.

endolymphatic sac

the blind, flattened cerebral end of the endolymphatic duct.

heart sac

the pericardium.

hernial sac

the peritoneal pouch that encloses a herniated viscus or mesentery.

lacrimal sac

see lacrimal sac.

paranal sac

see anal sacs.

pleural sac

the pleura-lined cavity which contains the lung.

ruminal sac

one of the dorsal and ventral sacs of the rumen which are themselves further subdivided to create a caudodorsal sac and a caudoventral sac.

yolk sac

the extraembryonic membrane connected with the midgut; in vertebrates other than true mammals, it contains a yolk mass. See also yolk sac.