Biology 322 Human Anatomy I Heart

Heart: Mass: 250-300 g Located in center of thorax (mediastinum) Anterior to vertebrae Posterior to sternum & 2nd through 6th ribs Superior to diaphragm Surrounded by lungs All vessels, nerves, etc. enter or leave superior end ("base")

3 Tissue Layers of Heart: (Outer Surface) Epicardium - Thin, connective tissue

3 Tissue Layers of Heart: (Outer Surface) Epicardium - Thin, connective tissue Myocardium - Thick, cardiac muscle

3 Tissue Layers of Heart: (Outer Surface) Epicardium - Thin, connective tissue Myocardium - Thick, cardiac muscle (Inner Surface) Endocardium - Thin, connective tissue Simple squamous epithelium lines inner surface, next to blood

Myocardium: Cardiac Muscle

Heart surrounded by double-layered pericardium Visceral Layer Parietal Layer Serous Pericardium Visceral Layer Parietal Layer Heart Pericardial Cavity

Heart surrounded by double-layered pericardium Fibrous Pericardium Serous Pericardium Visceral Layer Parietal Layer Heart Pericardial Cavity

Anterior View Aorta Superior Vena Cava Pulmonary Trunk Inferior Vena Cava

Anterior View Left Atrium Right Atrium Left Ventricle Right Ventricle

Anterior View Left Atrioventricular Sulcus Right Atrioventricular Sulcus Anterior Interventricular Suclus

Posterior View Right Atrium Left Atrium Right Ventricle Left Ventricle

Posterior View Left Atrioventricular Sulcus Right Atrioventricular Sulcus Posterior Interventricular Suclus

Posterior View Superior Vena Cava Aorta Pulmonary Arteries Inferior Vena Cava Pulmonary Veins

Left Coronary Artery Circumflex Coronary Artery Right Coronary Artery Anterior Interventricular Coronary Artery Marginal Coronary Artery

Circumflex Coronary Artery Right Coronary Artery Posterior Interventricular Coronary Artery

Anterior Cardiac Veins Great Cardiac Vein Small Cardiac Vein

Great Cardiac Vein Small Cardiac Vein Middle Cardiac Vein Coronary Sinus

Valves of the Heart: Right Atrioventricular Valve (Tricuspid valve) Right Atrium to Right Ventricle

Valves of the Heart: Right Atrioventricular Valve Pulmonary Valve (Right semilunar valve) Right Ventricle to Pulmonary Trunk

Valves of the Heart: Right Atrioventricular Valve Pulmonary Valve Left Atrioventricular Valve (Bicuspid or Mitral valve) Left Atrium to Left Ventricle

Valves of the Heart: Right Atrioventricular Valve Pulmonary Valve Left Atrioventricular Valve Aortic Valve (Left semilunar valve) Left Ventricle to Ascending Trunk

Valves of the Heart: Right Atrioventricular Valve Pulmonary Valve Left Atrioventricular Valve Aortic Valve Note: There are no valves controlling movement of blood a) From superior or inferior vena cavae into right atrium b) From pulmonary veins into left atrium

Intrinsic Cardiac Conduction System 1. Sinoatrial Node 2. Atrioventricular Node 3. Atrioventricular Bundle (of “His”) 4. Right and Left Bundle Branches 5. Purkinje Fibers