The atrium. (Plural: atria.)
The atria are found in the heart, specifically in the upper chambers. There are two atria in the heart, the left atrium and the right atrium, which receive blood from the veins and pump it into the ventricles.
Upper East side
The upper chamber on the right side of the heart.
The pulmonary arteries are the blood vessels that carry blood back up to the upper parts of the heart. There is one on each side of the heart that helps with this.
Ventricle (plural: ventricles)
The pulmonary arteries are the blood vessels that carry blood back up to the upper parts of the heart. There is one on each side of the heart that helps with this.
The Left Ventricle (Upper) and the Atrium (Lower)
The section of the heart that divides the left and right side of the heart is called the interventricular septum.
Blood
Section 311 is the upper deck pretty close to midfield on the side closest to the bridge
The heart is located in the upper left side of the chest under the lower half of the sternum.
The right atrium (upper chamber) and the right ventricle (lower chamber)