Akademik

A small cell, cavity, or socket. 1. SYN: pulmonary a.. 2. One of the terminal secretory portions of an alveolar or racemose gland. 3. One of the honeycomb pits in the wall of the stomach. 4. SYN: tooth socket. [L. dim. of alveus, trough, hollow sac, cavity]

- a. dentalis, pl.alveoli dentales [TA] SYN: tooth socket.

- pulmonary a. a thin-walled saclike terminal dilation of the respiratory bronchioles, alveolar ducts, and alveolar sacs across which gas exchange occurs between alveolar air and the pulmonary capillaries. SYN: a. (1) [NA], air cells (1), air vesicles, alveoli pulmonis, bronchic cells.

- alveoli pulmonis SYN: pulmonary a..

al·ve·o·lus al-'vē-ə-ləs n, pl -li -.lī, -(.)lē a small cavity or pit: as

a) a socket in the jaw for a tooth

b) any of the small thin-walled air-containing compartments of the lung that are typically arranged in saclike clusters into which an alveolar duct terminates and from which respiratory gases are exchanged with the pulmonary capillaries

c) an acinus of a compound gland

d) any of the pits in the wall of the stomach into which the glands open

n. (pl. alveoli)

1. (in the lung) a blind-ended air sac of microscopic size. About 30 alveoli open out of each alveolar duct, which leads from a respiratory bronchiole. The alveolar walls, which separate alveoli, contain capillaries. The alveoli are lined by a single layer of pneumocyte, which thus form a very thin layer between air and blood so that exchange of oxygen and carbon dioxide is normally rapid and complete. Children are born with about 20 million alveoli. The adult number of about 300 million is reached around the age of eight.

2. the part of the upper or lower jawbone that supports the roots of the teeth (see also mandible, maxilla). After tooth extraction it is largely absorbed.

3. the sac of a racemose gland (see also acinus).

4. any other small cavity, depression, or sac.

• alveolar adj.