The Heart Heart Orientation Mediastinum Base Apex Coverings Fibrous pericardium anchors heart and protects dense connective tissue Serous pericardium Parietal layer in between fibrous and visceral Visceral layer outermost surface of heart can be called epicardium Pericardial cavity between 2 layers filled with pericardium fluid which prevents friction and dissipates heat produced by heart Heart Layers Epicardium visceral layer Myocardium heart muscle itself invol muscle Endocardium continuous with endothelium Chambers and Markings Atria Ventricles Chambers and Markings Atria Ventricles Interatrial septum Chambers and Markings Atria Ventricles Interatrial septum Interventricular septum Chambers and Markings Atria Ventricles Interatrial septum Interventricular septum Coronary sulcus runs diagonally across front of heart Interventricular groove runs on back of heart between 2 ventricles Atria Auricles external extensions of the atria that increase surface area and allows atria to hold more blood Atria Auricles Pectinate muscles inside atria that coordinate action of atria Atria Auricles Pectinate muscles Fossa ovalis remnants of connection between atria in utero there is a shortcut which is the fossa ovalis foramen ovale is connection but it is cut off at birth Ventricles Trabeculae carneae Ventricles Trabeculae carneae Papillary muscles connect to heart wall function to open valves chordae tendonae connects Chamber related Blood Vessels Vena cava largest vein of body Superior drains upper part of heart into right atrium Inferior Chamber related Blood Vessels Vena cava Superior Inferior Coronary sinus where all veins empty empties into right atrium Chamber related Blood Vessels Vena cava Superior Inferior Coronary sinus Pulmonary veins return blood from lungs and empty into left atrium Right Left Chamber related Blood Vessels Vena cava Superior Inferior Coronary sinus Pulmonary veins Right Left Pulmonary artery Chamber related Blood Vessels Vena cava Superior Inferior Coronary sinus Pulmonary veins Right Left Pulmonary artery Aorta largest artery of body carries blood from left ventricle to rest of body Circulation Pulmonary circuit Systemic circuit Coronary Circulation Coronary arteries branch of aorta Anterior interventricular artery Circumflex artery Marginal artery Posterior interventricular artery Anatomy Joke of the Day Coronary Circulation Cardiac veins Great cardiac vein Middle cardiac vein Small cardiac vein Anterior cardiac veins Coronary sinus Anastomoses Control of Blood Flow Atrioventricular valves prevent backflow of blood into atria when ventricles are contracting Tricuspid side with 3 flaps Bicuspid mitral side with 2 flaps Control of Blood Flow Atrioventricular valves Tricuspid Bicuspid mitral Chordae tendineae attach to valves Control of Blood Flow Atrioventricular valves Tricuspid Bicuspid mitral Cordae tendineae Semilunar valves between ventricles and corresponding arterties Aortic left from aorta Pulmonary Cardiac Muscle Striated Uni nucleate Sliding filament mechanism of action Adjacent cells locked by desmosomes and gap junctions Intercalated discs communicating junction so it allows stimulation and makes heart function as one involuntary