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Atrium

Sometimes called auricle.

Refers to a chamber in which blood enters the heart, as opposed to the ventricle, where it is pushed out of the organ.

Thin-walled structure that allows blood to return to the heart.

The atrium receives blood as it returns to the heart to complete a circulating cycle, whereas the ventricle pumps blood out of the heart to start a new cycle.

The right atrium receives deoxygenated blood from the superior vena cava, inferior vena cava and coronary sinus.

The left atrium receives oxygenated blood from the left and right pulmonary veins.

The atria do not have valves at their inlets.

The inside of the atria is lined with rough musculae pectinati and crista terminalis, and the smooth walled part derived from the sinus venosus.

The fossa ovalis in the interatrial septum, is used in the fetal period as a means of bypassing the lung.

Two atria exist, one on either side of the heart.

The right atrium contains blood that is deoxygenated and sends blood to the right ventricle, which sends it to the lungs for oxygen.

Oxygenated blood is sent to the left atrium, and then is pumped to the left ventricle where it is sent to the aorta, which takes it to the rest of the body.

Allow uninterrupted venous flow to the heart during ventricular systole.

While cardiac output is pulsatile, the venous flow remains continuous and non-pulsatile.

When atrial function is impaired, venous flow becomes pulsatile, and circulation rate decreases.

The atrium is depolarized by Calcium.

Atria characteristics promote continuous venous flow in that there are no atrial inlet valves to int2242upt blood flow during atrial systole.

Atrial systole contractions are incomplete and do not block flow from the veins through the atria into the ventricles.

During atrial systole, blood not only empties from the atria to the ventricles, and continues to flow uninterrupted from the veins right through the atria into the ventricles.

Atria must relax before the start of ventricular contraction, to be able to accept venous flow without interruption.

Atrial contraction is 15% of the amount of the succeeding ventricular ejection, whereas the key benefit of atria is in preventing circulatory inertia and allowing uninterrupted venous flow to the heart.

Atrial myopathy refers to a range of abnormalities associated with disease of the left atrium with or without atrial fibrillation.

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