Chapter 18 Notes

A&PII: Ch. 18, page 1/5

Chapter 18: The Cardiovascular System: The Heart Heart Anatomy Approximately the size of a fist Location Enclosed in pericardium, a double-walled sac Pericardium Superficial fibrous pericardium Deep two-layered serous pericardium Layers of the Heart Wall Epicardium—visceral layer of the serous pericardium Myocardium Endocardium is continuous with endothelial lining of blood vessels Chambers Four chambers: two atria and two ventricles Atria: The Receiving Chambers Walls are ridged by pectinate muscles Vessels entering right atrium o Superior vena cava o Inferior vena cava o Coronary sinus Vessels entering left atrium o Right and left pulmonary veins Ventricles: The Discharging Chambers Walls are ridged by trabeculae carneae Papillary muscles project into the ventricular cavities Vessel leaving the right ventricle o Pulmonary trunk Vessel leaving the left ventricle o Aorta Pathway of Blood Through the Heart The heart is two side-by-side pumps o Right side is the pump for the pulmonary circuit  Vessels that carry blood to and from the lungs o Left side is the pump for the systemic circuit  Vessels that carry the blood to and from all body tissues Pathway of Blood Through the Heart Right atrium  tricuspid valve  right ventricle Right ventricle  pulmonary semilunar valve  pulmonary trunk  pulmonary arteries  lungs

A&PII: Ch. 18, page 2/5

Pathway of Blood Through the Heart Lungs  pulmonary veins  left atrium Left atrium  bicuspid valve  left ventricle Left ventricle  aortic semilunar valve  aorta Aorta  systemic circulation Coronary Circulation The functional blood supply to the heart muscle itself Arteries o Right and left coronary, marginal, circumflex, and anterior interventricular arteries Veins o Small cardiac, anterior cardiac, and great cardiac veins Homeostatic Imbalances Angina pectoris o Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium o Cells are weakened Myocardial infarction