The heart is located approximately

The heart is located approximately in the middle of the chest cavity. It is covered by a protective membrane, the pericardium.
Deoxygenated blood from the body enters the right atrium.
It flows through the tricuspid valve into the right ventricle. The term tricuspid refers to the three networks that form the flap valve.
Contraction of the ventricle then closes the tricuspid valve and forces open the pulmonary valve.
Blood flow to the pulmonary artery.
This branch soon, bringing blood to the right lung and left.
Here, give blood carbon dioxide and take in fresh oxygen supply.
The lung capillary when dried by the venules which is a subsidiary branch of the pulmonary blood vessels.
Two times the drainage of the lungs, carrying oxygenated blood to the heart of the left atrium