The heart is the center of the cardiovascular system. It is a hollow, muscular organ that weighs 250-350 grams, about 12 cm long and 9 cm wide at its broadest point, and 6 cm thick. It beats over 100,000 times a day to pump 7,000 liters of blood through over 40,000 kilometers of blood vessels.

The blood vessels form a network of tubes that carryblood from the heart to the tissues of the body and then return it to the heart.The right atrium receives blood from all parts of the body except lungs through three veins, and then delivers theblood into the right ventricle, which pumps the blood into the pulmonary trunk.

The pulmonary trunk divides into a right and left pulmonary artery, each of which carries blood to the lungs. In the lungs, the blood releases its carbon dioxide and takes on oxygen.

Blood returns to the heart through four pulmonary veins that empty intro the left atrium. The blood then passes into the left ventricle, which pumps the blood into the ascending aorta. From here the blood is passed into the blood vessels and their branches and later transported to the heart and other body parts. The flowing of the blood :

Know your heart and Protect your heart.