- One of the two smaller chambers of the heart. Each atrium consists of an open space with recessed walls. (The plural of atrium is atria.) The right atrium receives deoxygenated blood from the body through the vena cava and pumps it into the right ventricle which then sends it to the lungs. The left atrium receives oxygenated blood back from the lungs and pumps it down into the left ventricle for relatively high-pressure delivery to the body. The atrium was an open area in the center of an ancient Roman home. The atria of the heart are also called the auricles (the Latin auricula means little ear) because they resemble the floppy ears of a dog.
* * *1. [TA] A chamber or cavity to which are connected several chambers or passageways. 2. SYN: a. of heart. 3. That part of the tympanic cavity that lies immediately deep to the eardrum. 4. SYN: a. of middle nasal meatus. 5. In the lung, a subdivision of the alveolar duct from which alveolar sacs open. [L. entrance hall]- accessory a. SYN: cor triatriatum.- a. glottidis SYN: vestibule of larynx.- a. of lateral ventricle [TA] portion of lateral ventricle of brain common to the frontal, occipital, and temporal horns. SYN: a. ventriculi lateralis [TA], a. ventriculus lateralis [TA].- a. of lateral ventricle [TA] that portion of the lateral ventricle where the body (or central part), posterior horn, and temporal horn converge; it contains the choroid enlargement.- left a. of heart [TA] a. of the left side of the heart which receives the blood from the pulmonary veins. SYN: a. cordis sinistrum [TA], a. pulmonale, a. sinistrum cordis.- a. of middle nasal meatus [TA] the anterior expanded portion of the middle meatus of the nose, just above the vestibule. SYN: a. meatus medii nasalis [TA], a. meatus medii, a. (4), nasal a..- a. pulmonale SYN: left a. of heart.- right a. of heart [TA] right a., the a. of the right side of the heart that receives the blood from the venae cavae and coronary sinus. SYN: a. cordis dextrum [TA], a. dextrum cordis.
* * *atri·um 'ā-trē-əm n, pl atria -trē-ə also atri·ums an anatomical cavity or passage esp a chamber of the heart that receives blood from the veins and forces it into a ventricle or ventricles
* * *n. (pl. atria)1. either of the two upper chambers of the heart. Their muscular walls are thinner than those of the ventricles; the left atrium receives oxygenated blood from the lungs via the pulmonary vein; the right atrium receives deoxygenated blood from the venae cavae. See also auricle.2. any of various anatomical chambers into which one or more cavities open.• atrial adj.
* * *atri·um (aґtre-əm) pl. aґtria [L., from Gr. atrion hall] a chamber; used in anatomy to designate a chamber affording entrance to another structure or organ. Usually used alone to designate an atrium of the heart (a. cordis). atrial adj
Atria of the heart.
Medical dictionary. 2011.