Lipp Vis Nursing ChaptLWBK1630_C02_p013-068

14  Chapter 2 • Cardiovascular Care

NORMAL ANATOMY AND CONDUCTION SYSTEM OF THE HEART

Blood enters the heart through the superior vena cava and inferior vena cava. The blue arrows show the blood flow though the right atrium and right ventricle to the lungs and the red arrows show the blood flow from the lungs through the left atrium and left ventricle to the aorta. Normal heart sounds are created by closure of the four valves of the heart. S 1 , the first heart sound, the “lub,” occurs as a result of the closure of the tricuspid and mitral valves. S 2 , the second heart sound, the “dub,” occurs as a result of the closure of the pulmonic and aortic valves.

Aortic arch

Superior vena cava

Descending aorta Left pulmonary artery Pulmonary veins

Right pulmonary artery Interatrial septum

Pulmonary veins

Left atrium

Pulmonic valve Right atrium

Aortic valve Mitral valve Left ventricle

Tricuspid valve

Chordae tendinae Papillary muscle

Inferior vena cava

Right ventricle

Papillary muscle

Interventricular septum

Visceral pericardium Parietal pericardium

Endocardium

Myocardium

Unoxygenated blood Oxygenated blood

Epicardium

Pericardial space

Reprinted with permission from Hinkle JL, Cheever KH. Brunner & Suddarth’s Textbook of Medical- Surgical Nursing . 13th ed. Philadelphia: Wolters Kluwer; 2013.

SA node

Left atrium

AV node

Bundle of His

Right atrium

Left ventricle

Right ventricle

Left bundle branch Purkinje fibers

Electrical impulses originate in the SA node, travel to the AV node, down the bundle of His to the Purkinje fibers. Blood flow through the heart and the body is dependent on synchronization of the electrical system.

Right bundle branch

Reprinted with permission from Hinkle JL, Cheever KH. Brunner & Suddarth’s Textbook of Medical-Surgical Nursing. 13th ed. Philadelphia: Wolters Kluwer; 2013.