Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley For the Dental Hygienist CHAPTER Understanding EKGs A Practical Approach 1 The Anatomy of the Heart: Structure

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Anatomy of the Heart Objectives –Describe the chambers of the heart  Atria  Ventricles –Identify the location, shape, and size of the heart –Name the layers of the heart –Name the valves of the heart

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Anatomy of the Heart Objectives (continued) –Describe the structure and function of the blood vessels  Arteries  Veins  Capillaries –Discuss concept of pulmonary circulation –Explain the concept of systemic circulation

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Anatomy of the Heart The heart is muscle Myocardium –Heart muscle –“Two-sided pump” Atrium (atria) –Upper chambers –Separated by interatrial septum –Coronary sulcus-surrounds outside of heart and divides the atria from the ventricles

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Anatomy of the Heart Ventricles –Lower chambers –Separated by interventricular septum

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Location, Size, and Shape of the Heart

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Location, Size, and Shape of the Heart Located in mediastinum –Lying in front of spinal column, behind sternum, and between lungs –2/3 lies to left of midline –Apex lies just above diaphragm –Base lies at level of the third rib –Size of owner’s closed fist

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Location, Size, and Shape of the Heart

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Location, Size, and Shape of the Heart

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Layers of the Heart Pericardium –Closed, two-layered sac Parietal pericardium –Tough, non-elastic, fibrous connective tissue Visceral pericardium –Thin, serous inner layer of pericardium –Pericarditis-inflammation of the serous pericardium  Excess of fluid in pericardial sac is called cardiac tamponade  Condition is an EXTREME EMERGENCY!!!

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley The Heart Wall Epicardium –Smooth outer surface  Coronary arteries located on the surface of Epicardium Myocardium –Thick, middle layer of the heart, composed of cardiac muscle cells, responsible for ability to contract Endocardium –Innermost layer, composed of connective tissue  Requires constant and uninterrupted oxygen supply

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Valves of the Heart Four valves allow blood to flow in one direction Two sets –Atrioventricular valves –Semilunar valves

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Atrioventricular Valves Located between atria and the ventricles Allow flow from atria into ventricles Prevent flow backward from ventricles Tricuspid valve –Three cusps –Located between right atrium and right ventricle

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Atrioventricular Valves Mitral (bicuspid) valve –Two cusps –Located between left atrium and left ventricle

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Semilunar Valves Prevent backflow of blood into the ventricles Each valve contains three semilunar, or moon-shaped cusps Pulmonic valve –Located between right ventricle and pulmonary artery Aortic valve –Located between left ventricle and trunk of aorta

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Heart Valves Function Chamber pressure governs opening and closing of heart valves Ventricular systole –Contraction of ventricles  Atrioventricular valves close and semilunar valves open

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Heart Valves Function Ventricular diastole –Relaxation of ventricles  Atrioventricular valves are open and semilunar valves are closed

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Blood Vessels Blood vessels are the “container” for fluid or blood –Arteries –Veins –Capillaries

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Arteries Thick wall and muscular Function under high pressure Carry blood AWAY FROM heart Regulates blood pressure by changes in peripheral vascular resistance Arteries –Larger vessels Arterioles –Small vessels

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Arteries

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Arterial Wall Layers

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Coronary Arteries and Coronary Sinus Coronary Arteries –Two main coronary arteries –The right and the left –Arise from the trunk of the aorta –Provide oxygenated blood throughout the heart muscle

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Coronary Arteries and Coronary Sinus Left Coronary Artery –Divides into the left anterior descending artery and circumflex artery –Anterior descending supplies most of anterior portion of the heart –Circumflex extends around to posterior side of heart –Major branch supplies lateral wall of left ventricle

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Coronary Arteries and Coronary Sinus Right Coronary Artery –Extends around to posterior portion of heart –Branches supply blood to lateral wall –Posterior interventricular artery supplies posterior and inferior part of left ventricle –Also supplies a portion of the electrical conduction system

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Coronary Arteries and Coronary Sinus Coronary Sinus {also called the Great Cardiac Vein} –Serves to receive deoxygenated blood from the veins of the myocardium –Empties into the right atrium

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Veins Vessels that carry blood back to the heart Venules –Smaller vessels Operate under low pressure

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Capillaries Tiny blood vessels whose walls are thinnest of all Vast majority of gas exchange occurs Circulation –Movement through a course (body) that leads back to initial point (heart)

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Circulation

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Capillaries

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Pulmonary Circulation Blood flow between the heart and lungs –Bloodleaves heart through right ventricle, travels into PULMONARY artery to lungs and back through PULMONARY veins to left atrium

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Systemic Circulation Blood flow between the heart and body –Blood leaves the left ventricle, travels through the arteries, capillaries, and veins of the BODY SYSTEM and back to the right atrium

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Understanding EKGs: A Practical Approach, Third Edition Brenda M. Beasley Summary Understanding anatomy of heart and blood vessels will assist you in the understanding of dysrhythmias and their causes ANY QUESTIONS?