atrium

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atrium

 [a´tre-um] (pl. a´tria) (L.)
a chamber affording entrance, especially the upper chamber (a´trium cor´dis) on either side of the heart, transmitting to the ventricle of the same side blood received from the pulmonary veins (left atrium) and from the venae cavae (right atrium).

a·tri·um

, pl.

a·tri·a

(ā'trē-ŭm, ā'trē-ă), Do not confuse this word with antrum.
1. A chamber or cavity to which are connected several chambers or passageways.
2. Synonym(s): atrium of heart
3. That part of the tympanic cavity that lies immediately deep to the tympanic membrane.
5. In the lung, a subdivision of the alveolar duct from which alveolar sacs open.
[L. entrance hall]

atrium

/atri·um/ (a´tre-um) pl. a´tria   [L.] a chamber; in anatomy, a chamber affording entrance to another structure or organ, especially the upper, smaller cavity (a. cordis) on either side of the heart, which receives blood from the pulmonary veins (left a.) or venae cavae (right a.) and delivers it to the ventricle on the same side.a´trial
Enlarge picture
Atria of the heart.

common atrium  the single atrium found in a form of three-chambered heart.

atrium

(ā′trē-əm)
n. pl. atria (ā′trē-ə) or atri·ums
Anatomy A body cavity or chamber, especially either of the upper chambers of the heart that receives blood from the veins and forces it into a ventricle. Also called auricle.

atrium

pl. atria [ā′trē·əm]
Etymology: L, hall
a chamber or cavity, such as the right and left atria of the heart or the nasal cavity.

a·tri·um

, pl. atria (ā'trē-ŭm, -ă) [TA]
1. A chamber or cavity to which are connected several chambers or passageways.
2. Synonym(s): atrium of heart.
3. That part of the tympanic cavity that lies immediately deep to the tympanic membrane (eardrum).
4. In the lung, a subdivision of the alveolar duct from which alveolar sacs open.
[L. entrance hall]

atrium

One of the thin-walled upper chambers of the heart which receive blood from the veins and pass it down to the lower, more powerful, pumping chambers (the ventricles).
Atriumclick for a larger image
Fig. 56 Atrium . Primitive heart.

atrium

(pl. atria) a passage or chamber in the body, particularly one or more of the chambers in the heart receiving blood from the body. All vertebrates except fish have hearts with two atrial cavities.

See also HEART and HEART, CARDIAC CYCLE.

Atrium

One of the two upper chambers of the heart.
Figure 1: The nervous system.

atrium

(from the Latin for cavity, entrance or passage). One of the two upper receiving chambers of the heart. The left atrium receives pulmonary venous blood (oxygenated, from the lungs) and the right atrium receives systemic venous blood (partly deoxygenated, from the rest of the body). atria pl, atrial adj. See Figure 1.

a·tri·um

, pl. atria (ā'trē-ŭm, -ă) [TA] Do not confuse this word with antrum.
Chamber or cavity to which are connected several chambers or passageways.
[L. entrance hall]

atrium

pl. atria [L.] a chamber affording entrance, especially the chamber (atrium cordis) on either side of the heart, transmitting to the ventricle of the same side blood received (left atrium) from the pulmonary veins and (right atrium) from the venae cavae. See also atrial.

parabronchi atrium
extensions of the parabronchial lumen giving rise to the air capillaries.
atrium partitioning
partitioning of the atrium by the septum primum during embryological development may be defective leading to a congenital malformation, e.g. patent foramen ovale.
ruminal atrium
the first part of the rumen, and the cranial chamber of its dorsal sac, just caudal to the reticuloruminal fold. Called also atrium ruminis.
ventricular atrium
the shallow vault between the reticulum and the rumen into which the esophagus in the ruminant opens.