Anatomy and Function of the Heart

Anatomy and Function of the Heart

• The heart is composed of three layers: the epicardium, myocardium, and endocardium.
• Cardiac muscle tissue forms the thick layer of myocardium and is responsible for pumping blood through the heart.
• The chambers of the heart include the right atrium, right ventricle, left atrium, and left ventricle.
• The heart valves, including the atrioventricular (AV) valves and semilunar valves, regulate blood flow based on blood pressure.
• The coronary arteries deliver oxygen-rich blood to the cardiac muscle, while cardiac veins drain deoxygenated blood back to the right atrium.
• The heart beats rhythmically due to the autorhythmicity of specialized cardiac muscle cells.
• The intrinsic conduction system includes the SA node, AV node, and Purkinje fibers, which set the pace of the heartbeat and delay the transmission of action potentials.
• Heart sounds, known as "lubb" and "dupp," are caused by the closing of the AV valves and semilunar valves, respectively.
• Abnormalities of the heart can include extrasystole, ventricular fibrillation, complete heart block, myocardial infarction, and congestive heart failure.
• Ventricular systole occurs in two phases: isovolumic contraction and ventricular ejection.
• Cardiac output is the amount of blood pumped by each ventricle in one minute, and it is determined by heart rate and stroke volume.
• Factors affecting cardiac output include autonomous innervation, hormones, cardiac reflexes, Starling's Law, and venous return.