Text Descriptions of Healthy Heart Pictures

Blood Vessels of the Heart

Illustration of a pulsing heart showing an external view of the blood vessels going into and out of the heart, an internal view of the blood vessels going into and out of the heart, and the coronary arteries filling with blood during each heart beat.

Chambers of the Heart

Illustration of the inside of the heart, showing the two upper chambers (right atrium and left atrium) and the two lower chambers (right ventricle and left ventricle). The atrial septum divides the atria; the ventricular septum divides the ventricles.

Blood Flow through the Heart

Illustration of the heart and lungs, showing the major blood vessels that attach to the heart. Blood returns to the heart’s upper chambers from the body and lungs. The valves between the atria and the ventricles open, the atria contract, and blood flows into your ventricles. When the ventricles are full, the valves close, creating the first heart sound, “Lubb.”

Then, the valves between the ventricles and the blood vessels open, your ventricles contract, and blood is pumped to your body and lungs. These valves close, creating the second heart sound, “Dubb.”

And the cycle starts over.

Heart Valves

Illustration of the inside of the heart, showing the four major valves that allow blood to flow in and out of the chambers of the heart and prevent the blood from flowing backward.

The pulmonary valve allows blood to flow from the right ventricle into the pulmonary arteries. The tricuspid valve allows blood to flow from the right atrium to the right ventricle. The aortic valve allows blood to flow from the left ventricle to the aorta. The mitral valve allows blood to flow from the left atrium to the left ventricle.

The mitral valve and the tricuspid valve (the atrioventricular valves) are located between the atria and the ventricles. The aortic valve and the pulmonary valve (the semilunar valves) are located between the ventricles and the arteries that lead away from the heart.

The heart valves open and shut when the heart contracts and relaxes. They prevent blood from flowing backwards during the contractions.

The Electrical System of the Heart

Illustration of the inside of the heart, showing the transmission of electrical signals throughout the heart. The SA node starts the signal, causing the atria to contract. This signal travels into the AV node and through the bundle of His. The signals then travel down the bundle branches and Purkinje fibers, causing the ventricles to contract.