The Heart

Membranes Pericardium Covers the heart Visceral – innermost layer Parietal – outermost layer Pericardial fluid: serous fluid found between visceral & parietal layers reduces friction

Heart Wall Epicardium (visceral pericardium): outer covering Myocardium: cardiac muscle tissue Endocardium: epithelial & connective tissue; continuous with inner linings of blood vessels attached to heart

Heart Parts

A: Superior Vena Cava B: R. Pulmonary Artery C: R. Pulmonary Vein D: R. Atrium E: Tricuspid Valve F: R. Ventricle G: Inferior Vena Cava H: Myocardium (Septum) I: L. Ventricle J: Bicuspid Valve K: Pulmonary Valve L: L. Atrium M: L. Pulmonary Vein N: Pulmonary Trunk O: Aorta

Chambers Atria (right & left): thin walls, upper chambers; receive blood returning to the heart Ventricles (right & left): lower chambers; receive blood from atria, contract to force blood into arteries Septum: divides heart into right & left sides

Valves 2 Artioventricular (AV) valves: prevent backflow of blood into atria Tricuspid valve: between RA & RV Bicuspid Valve: between LA & LV Chordae tendineae = fibrous strings that attach from papillary muscles to valve; open valves Papillary muscles = small mounds of cardiac muscle tissue Aortic valve: prevents backflow of blood into L ventricle from aorta Pulmonary Valve: prevents backflow of blood into R ventricle from pulmonary trunk

Essential Blood Vessels Pulmonary trunk: divides to form R/L pulmonary arteries, which carry blood into lungs from R ventricle R/L pulmonary veins: carry blood from lungs to L atrium Aorta: large artery, carries blood away from heart to body

Blood Flow pattern

Khan Academy Video: https://www.youtube.com/watch?v=7XaftdE_h60 Fetal Heart https://www.youtube.com/watch?v=cgccQVcFLi4