The Heart Membranes Pericardium Covers the heart Visceral

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=7 Xaftd E_h 60 • Fetal Heart https: //www. youtube. com/watch? v=cgcc. QVc FLi 4