Different Parts of Human Heart
The parts of your heart are like the parts of a building. Your heart anatomy includes:
Walls.
Chambers that are like rooms.
Valves that open and close like doors to the rooms.
Blood vessels like plumbing pipes that run through a building.
An electrical conduction system like electrical power that runs through a building.
Heart walls
Your heart walls are the muscles that contract (squeeze) and relax to send blood throughout your body.
A layer of muscular tissue called the septum divides your heart walls into the left and right sides.
Your heart walls have three layers:
Endocardium: Inner layer.
Myocardium: Muscular middle layer.
Epicardium: Protective outer layer.
The epicardium is one layer of your pericardium. The pericardium is a protective sac that covers your
entire heart. It produces fluid to lubricate your heart and keep it from rubbing against other organs.
Heart chambers
Your heart has four separate chambers. You have two chambers on the top (atrium, plural atria) and
two on the bottom (ventricles), one on each side of your heart.
Right atrium: Two large veins deliver oxygen-poor blood to your right atrium. The
superior vena cava carries blood from your upper body. The inferior vena cava brings blood from
your lower body. Then the right atrium pumps the blood to your right ventricle.
Right ventricle: The lower right chamber pumps the oxygen-poor blood to your lungs through
the pulmonary artery. The lungs reload the blood with oxygen.
Left atrium: After the lungs fill your blood with oxygen, the pulmonary veins carry the blood to
the left atrium. This upper chamber pumps the blood to your left ventricle.
Left ventricle: The left ventricle is slightly larger than the right. It pumps oxygen-rich blood to
the rest of your body.
Heart valves
Your heart valves are like doors between your heart chambers. They open and close to allow blood to
flow through. They also keep your blood from moving in the wrong direction.
Atrioventricular valves
The atrioventricular (AV) valves open between your upper and lower heart chambers. They include:
Tricuspid valve: Door between your right atrium and right ventricle.
Mitral valve: Door between your left atrium and left ventricle.
Semilunar valves
Semilunar (SL) valves open when blood flows out of your ventricles. They include:
Aortic valve: Opens when blood flows out of your left ventricle to your aorta (artery that carries
oxygen-rich blood to your body).
Pulmonary valve: Opens when blood flows from your right ventricle to your pulmonary
arteries (the only arteries that carry oxygen-poor blood to your lungs).
Blood vessels
Your heart pumps blood through three types of blood vessels:
Arteries carry oxygen-rich blood from your heart to your body’s tissues. The exception is your
pulmonary arteries, which go to your lungs.
Veins carry oxygen-poor blood back to your heart.
Capillaries are small blood vessels where your body exchanges oxygen-rich and oxygen-poor
blood.
Coronary arteries
Your heart receives nutrients through a network of coronary arteries. These arteries run along your
heart’s surface. They serve the heart itself and include the:
Left coronary artery: Divides into two branches (the circumflex artery and the left anterior
descending artery).
Circumflex artery: Supplies blood to the left atrium and the side and back of the left ventricle.
Left anterior descending artery (LAD): Supplies blood to the front and bottom of the left
ventricle and the front of the septum.
Right coronary artery (RCA): Supplies blood to the right atrium, right ventricle, bottom
portion of the left ventricle and back of the septum.
