Pulmonary Trunk: takes blood into the lungs to oxygenate them

Myocardium: middle most thick layer, consists of cardiac muscle, pumps blood out of heart chambers

Pericardial cavity: space between the visceral and parietal layers,
contains serous fluid to reduce friction between the layers

Parietal pericardium: outer layer of the serous membrane, lines the inner surface of the fibrous pericardium

Endocardium: innermost layer, made up of CT and epithelium, continuous with the endothelium of major vessels
joining the heart, contains the Purkinje fibers

Epicardium (visceral pericardium): outermost layer, serous membrane that is made up of CT and epithelium (decreases friction in heart)

Deoxygenated blood from the body goes into the heart from the superior/ inferior vena cava into the right atrium, through the tricuspid valve into the right ventricle. From the right ventricle it goes through the pulmonary semilunar valve into the pulmonary artery which goes into the lungs to get oxygenated. Once oxidized, it goes back into the heart from the pulmonary vein into the left atrium, through the bicuspid valve into the left ventricle. From the left ventricle it goes out from the aortic semilunar valve out the aorta and the blood is then distributed throughout the body and the cycle starts again.

Tunica externa: Innermost endothelial layer composed of simple squamous epithelium, creates a smooth surface to prevent clots, secretes biochemicals (prevents platelet aggregation), regulates blood flow

Exchanges respiratory gases, nutrients, and metabolic wastes occurs between capillaries and tissue fluid near the body cells, via mostly diffusion

Superior/ Inferior Vena Cava: carries deoxygenated blood into heart (right atrium)

Pulmonary Veins: takes oxygenated into the heart (left atrium)

QRS Complex: depolarization of ventricles (leads to contraction of the ventricles; the repolarization of the atria
occurs during the QRS complex)

Contraction and relaxation of the atria and ventricles to pump blood throughout the body