Epicardium - ✔Thin outermost layer of the heart, contains coronary arteries.
Myocardium - ✔Middle muscular layer of the heart, contains electrical system.
Endocardium - ✔Inner most layer of the heart, lines chambers and valves.
Blood flow through the heart - ✔Venules --> Veins --> Superior/Inferior VC --> Rt atria --> Tricuspid Valve --> Rt ventricle --> Pulmonary valve --> Pulmonary Artery --> Lungs --> Pulmonary Veins --> Lt
atria --> Bicuspid/Mitral valve --> Lt ventricle --> Aortic Valve --> Aorta --> Arteries --> Arterioles --> Capillaries --> Body
Deoxygenated blood(left side of heart) - ✔Venules --> Veins --> Superior/Inferior VC --> Rt atria --> Tricuspid Valve --> Rt ventricle --> Pulmonary valve --> Pulmonary Artery
Oxygenated blood(right side of heart) - ✔Pulmonary Veins --> Lt atria --> Bicuspid/Mitral valve --> Lt ventricle --> Aortic Valve
--> Aorta --> Arteries --> Arterioles --> Capillaries
Atrioventricular Valves(diastole) - ✔Valves between the atria and ventricles. Tricuspid, Bicuspid/Mitral. Regulates blood flow IN the heart.
Semilunar Valves(systole) - ✔Pulmonary and Aortic valves separates Ventricles from corresponding artery. Regulates blood flow OUT of the heart.
sinoatrial node (SA node) - ✔Primary pacemaker, 60-100bpm intrinsic rate
atrioventricular node (AV) node - ✔2nd pacemaker, 40-60bpm intrinsic rate