Human Anatomy (Heart)

Daily cardiac output

Approximately 3,600 gallons of blood through 75,000 miles of vessels.

Heart beats per day

About 100,000 times per day.

Epicardium

The outer layer of the heart wall, synonymous with the visceral serous pericardium.

Myocardium

The middle cardiac muscle layer that contracts to pump blood.

Endocardium

The smooth inner lining of the heart chambers.

Right atrium blood sources

Superior vena cava, inferior vena cava, and coronary sinus.

Right atrium interior features

Pectinate muscles and the fossa ovalis.

Papillary muscle function

Tighten chordae tendineae to prevent AV valve eversion during ventricular contraction.

Atrioventricular (AV) valves

Tricuspid valve (right) and Bicuspid/Mitral valve (left).

Semilunar (SL) valves

Pulmonary valve and Aortic valve.

Left coronary artery branches

Anterior interventricular branch and circumflex branch.

Right coronary artery branches

Posterior interventricular branch and marginal branch(es).

Coronary venous drainage path

Cardiac veins to coronary sinus to the right atrium.

Cardiac conduction sequence

SA node, AV node, AV bundle, bundle branches, Purkinje fibers.

First heart sound (S₁)

Produced by the closure of the AV valves.

Second heart sound (S₂)

Produced by the closure of the SL valves.

Conducting zone (respiratory)

Airway zone that ends at the terminal bronchioles.

Respiratory zone (respiratory)

Zone beginning at the respiratory bronchioles through alveoli.