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.
Right Atrium.
it depends how you are born
The lungs, I the alviolies.
Yes and no. When a valve is open, it is allowingblood to enter the heart's chambers. When a valve is closed, it is preventing blood from entering a chamber.