De-oxygenated blood is dark red. Oxygenated blood is bright red. Both enter the heart- the former enters the right heart; the latter enters the left heart.
heart
heart
Veins carry deoxygenated blood back the heart.
Depleted blood enters and leaves the right side of the heart.
Actually it is the Left Atrium
It flows through the pulmonary vein toward the heart.
The pulmonary vein enters the left atrium of the heart.
Deoxygenated blood return form the body to the heart via the Superior and Inferior Vena Cavas, which join together to enter the Heart's Right Atrium.
it depends how you are born
Right Atrium.
The lungs, I the alviolies.
Veins return blood to the heart. Four veins enter the heart. The superior vena cava (SVC) returns blood from the head, neck and arms and enters the right atrium of the heart. The inferior vena cava (IVC) returns blood from the rest of the body and also enters the right atrium of the heart. The left and right pulmonary veins return blood from the lungs and enter the left atrium.