1.Basic Cardiac TheHeart

2. The Heart To understand the ECG, it helps to understandthe heart and how the heart works 3. The Heart Fun Fact The average heart beats 100,000 times, pumpingabout 2,000 gallons of blood each day!! 4. The Heart Fun Fact The adult heart weighs approximately 11oz and isabout the size of its owners fist A persons heart size and weight are influenced by their age, body weight and build, frequency of physical exercise, and heart disease 5. The Heart Your heart is a muscular organ that acts like apump to send blood throughout your body Your heart is located under the ribcage in thecenter of your chest between your right andleft lung Your heart is at the center of your circulatorysystem, which delivers blood to all areas ofyour body 6. The Heart Your Heart is vital to your health and nearlyeverything that goes on in your body Without the hearts pumping action, blood cantcirculate within your body Your blood carries the oxygen and nutrientsthat your organs need to function normally. Blood also carries carbon dioxide, a wasteproduct, to your lungs to be passed out of yourbody and into the air 7. The Heart Pericardium Protective sac that surrounds the heart Within the pericardium is about 10 mL of serous fluid that acts as a lubricant, preventing friction as the heart beats 8. Heart Chambers The inside of your heart is divided into fourchambers 9. Heart Chambers The two upper chambers of your heart arecalled atria The atria receive and collect blood 10. Heart Chambers The right atrium Receives deoxygenated blood returning from thebody through the inferior and superior vena cavaeand from the heart through the coronary sinus 11. Heart Chambers The left atrium Receives oxygenated blood from the lungsthrough the four pulmonary veins 12. Heart Chambers The interatrial septum divides the chambersand helps them contract Contraction of the atria forces blood into theventricles below 13. Heart Chambers The two lower chambers of your heart arecalled ventricles The ventricles pump blood out of your heartinto the circulatory system to other parts ofyour body 14. Heart Chambers Right ventricle Receives blood from the right atrium and pumps itthrough the pulmonary arteries to the lungs,where it picks up oxygen and drops off carbondioxide 15. Heart Chambers Left ventricle Receives oxygenated blood from the left atriumand pumps it through the aorta and then out tothe rest of the body 16. Heart Chambers The right and left sides of your heart aredivided by an internal wall of tissue called theseptum 17. Great Vessels There are blood vessels attached to the heartthat transport blood to and from the lungsand body Pulmonary arteries and veins Aorta Superior and inferior vena cava 18. Great Vessels Pulmonary arteries and veins Transfer blood between the heart and lungs 19. Great Vessels Aorta Delivers oxygenated blood from the heart to thebody 20. Great Vessels Superior and Inferior Vena Cava Send unoxygenated blood from the body to theheart 21. The Heart as a Pump The left side Pumps oxygenated blood and nutrients to thebodys organs, muscles, and tissues The right side Pumps deoxygenated blood to the lungs toexchange carbon dioxide for oxygen 22. Heart Valves With each heartbeat, the heart relaxes andcontracts During relaxation The heart relaxes and fills with blood During contraction The heart squeezes and pumps blood out to thebody 23. Heart Valves For the heart to function properly, your bloodflows in only one direction Your hearts valves make this possible 24. Heart Valves The valves make sure the blood travels in onlyone direction Blood travelsfrom the bodyto the rightatrium Through the Through the aortic valve into tricuspid valvethe aorta and into the right out to the body ventricle Traveling intoThrough thethe left atrium, pulmonic valvethrough theinto themitral valve into pulmonarythe leftarteriesventricle 25. Heart Valves Healthy valves open and close in very exactcoordination with the pumping action of yourhearts atria and ventricles When your heart beats, the valves make aLUB-DUB sound that can be heard with astethoscope 26. Heart Valves Four Valves of the Heart Aortic Mitral Pulmonary Tricuspid 27. Heart Valves Tricuspid valve Regulates blood flow between the right atriumand right ventricle 28. Heart Valves Pulmonary valve Controls blood flow from the right ventricle intothe pulmonary artery, which carries blood to yourlungs to pick up oxygen 29. Heart Valves Mitral valve Lets oxygen-rich blood from your lungs pass fromthe left atrium into the left ventricle 30. Heart Valves Aortic valve Opens the way for oxygen-rich blood to pass fromthe left ventricle into the aorta, your bodyslargest artery, where it is delivered to the rest ofyour body 31. Heart ValvesAtrioventricular (AV) Semilunar (SL) Tricuspid valve Pulmonic valve Right side of the heart Right side of the heart Separates right atrium and Between right ventricle and right ventricle pulmonary artery Mitral valve (bicuspid) Aortic valve Left side of the heart Left side of the heart Separates left atrium and left Between left ventricle and ventricle aorta 32. Coronary circulation The heart has its own circulatory system tosupply it with oxygen (coronary arteries) andto remove deoxygenated blood (coronaryveins) 33. Myocardial Ischemia and Infarction Myocardial ischemia Occurs when the flow of blood through a coronaryartery is decreased, the cardiac muscle tissue fedby the coronary artery is deprived of oxygen andnutrients 34. Myocardial Ischemia and Infarction Myocardial Infarction (MI) or Heart Attack Occurs when one of the arteries that supplies theheart muscle becomes blocked Blockage may be caused by spasm of the artery orby atherosclerosis with acute clot formation The blockage results in damaged tissue and apermanent loss of contraction of this portion ofthe heart muscle 35. Layers of the Heart Wall The heart wall is made up of three tissuelayers Epicardium Myocardium Endocardium 36. Layers of the Heart Wall Epicardium Is the external or outer layer of the heart. This iswhere the coronary arteries and veins are found 37. Layers of the Heart Wall Myocardium Is the middle and thickest layer of the heart and isresponsible for the contraction of the heart 38. Layers of the Heart Wall Endocardium Is the innermost layer of the heart 39. Cardiac Cells There are two basic types of cardiac cells inthe heart: Pacemaker Myocardial cells 40. Cardiac Cells Pacemaker cells (electrical cells) Responsible for the spontaneous generation andconduction of electrical impulses Found in the electrical conduction system of theheart 41. Cardiac Cells Myocardial cells (working cells) Contain contractile filaments that areinterconnected When electrically stimulated, the filaments slidetogether and the myocardial cell contracts These cells form the myocardium (muscular layerof the heart) These are the working cells and are responsiblefor contraction and relaxation 42. Properties of Cardiac Cells Automaticity Is the ability of the pacemaker cells tospontaneously initiate an electrical impulse. Onlypacemaker cells have the property of automaticity fires impulses regularly Contractility Refers to the ability of the myocardial cells toshorten causing cardiac muscle contraction inresponse to an electrical stimulus 43. Properties of Cardiac Cells Conductivity Is a property that refers to the ability of all cardiac cells to receive and conduct an electrical impulse to an adjacent cardiac cell Excitability Refers to the electrical irritability of all cardiac cells because of an ionic imbalance across the membranes of cells 44. Properties of Cardiac CellsType of Cardiac Cell Where Found Primary FunctionPropertiesMyocardial cells MyocardiumContraction and Contractilityworking cellsrelaxationExcitabilityPacemaker cellsElectricalGeneration andAutomaticityElectrical cells conduction system conduction of Conductivity electrical impulses Excitability 45. Autonomic Nervous System Effects onthe Heart The nervous system innervates the heart andalters the heart rate, force of contraction,cardiac output, and blood pressure whenstimulated 46. Autonomic Nervous System Effects onthe Heart Parasympathetic nerve fibers Originate from the inhibitory center of the brainvia the vagus nerve Stimulation of this nerve causes the release of acetylcholine, which decreases the heart rate, force of contraction, cardiac output , and blood pressure 47. Autonomic Nervous System Effects onthe Heart Sympathetic nerve fibers Originate from the accelerator center in the brain Stimulation of these nerve fibers results in therelease of norepinephrine, which increases theheart rate, force of contraction, cardiac output,and blood pressure 48. Understanding the Hearts Electrical System The heart has an internal electrical system thatcontrols the speed and rhythm of the heartbeat. With each heartbeat, an electrical signal spreadsfrom the top of the heart to the bottom As it travels, the electrical signal causes the heartto contract and pump blood The process repeats with each new heartbeat A problem with any part of this process can causean arrhythmia 49. Understanding the Hearts Electrical System 50. Understanding the Hearts ElectricalSystem The normal conduction Pathway The SA node fires causing atria to contract and pumpblood into the ventricles The impulse travels through the atria to the AV node The AV node briefly delays the impulse allowing time for the ventricles to fill with blood The impulse then travels through the Bundle of HIS,right and left bundle branches and Purkinje fibers Causing the ventricles to contract The ventricles then relax, then the heartbeat processstarts all over again in the SA node Youtube: The Hearts electrical system (0.27) 51. Parts of the Electrical Conduction System SA node AV node Bundle of His Right and Left Bundle Branches Purkinje Fibers 52. Parts of the Electrical Conduction System SA (Sino-atrial) node Located in the right upper atrium Called the normal pacemaker of the heart It initiates the electrical impulse that is sent through the heart 53. Parts of the Electrical Conduction System AV (atrioventricular) node Located in the lower right atrium and functions asa gatekeeper to the ventricles It delays the impulses from the SA node and atriafor a fraction of a second before sending theimpulse to the ventricles It also will prevent extra beats from beingconducted to the ventricles 54. Parts of the Electrical Conduction System Bundle of His Directly attached to the AV node and extendsfrom the top left corner of the right ventricle tothe top of the intraventricular septum It sends the impulses from the AV node rapidly tothe lower part of the conduction system in theventricles 55. Parts of the Electrical Conduction System Right and Left Bundle Branches Divided from the Bundle of His Found in the intraventricular septum and acrossthe lower portion of the right and left ventricles 56. Parts of the Electrical Conduction System Purkinje Fibers Subdivided into smaller fibers from the right andleft bundle branches Distribute the electrical impulse from the bundlebranches to the individual muscle cells in theventricles 57. Understanding the Hearts ElectricalSystem The normal conduction Pathway The SA node fires causing atria to contract and pumpblood into the ventricles The impulse travels through the atria to the AV node The AV node briefly delays the impulse allowing time for the ventricles to fill with blood The impulse then travels through the Bundle of HIS,right and left bundle branches and Purkinje fibers Causing the ventricles to contract The ventricles then relax, then the heartbeat processstarts all over again in the SA node Youtube: The Hearts electrical system (0.27) 58. Pacemaker Sites of the Conduction System There are three intrinsic pacemaker siteswithin the conduction system Each site can produce an electrical impulse orimpulses and control the heart rate 59. Pacemaker Sites of the Conduction System The intrinsic rate of each site is as follows: SA node 60-100 bpm AV junction 40-60 bpm Ventricles 20-40 bpm 60. Pacemaker Sites of the Conduction System Normally, the SA node is the pacemaker of theheart If the sinus node slows down or fails to initiatedepolarization (contraction), either the AVjunction or the ventricles will spontaneouslyproduce electrical impulses 61. The Cardiac Cycle The period from the beginning of oneheartbeat to the beginning of one heartbeatto the beginning of the next one Consists of 2 events Mechanical Electrical 62. The Cardiac Cycle Mechanical Events The mechanical part of the cardiac cycle is dividedinto two phases: diastole (rest) and systole(contraction). The atria and ventricles contractand relax in tandem to effectively pump bloodthrough the heart 63. The Cardiac Cycle Mechanical Events During atrial systole (contraction) and ventriculardiastole (relaxation), the atria conract and squeezeblood into the ventricles The ventricles are at rest and fill with blood 64. The Cardiac Cycle Mechanical Events During atrial diastole (relaxation) and ventricularsystole (contraction), the atria are at rest and fillwith blood, while the ventricles contract andsqueeze blood out of the heart 65. The Cardiac Cycle Electrical Events The electrical events that occur in the heartmuscle are called depolarization andrepolarization The exchange of electrolytes (minerals in yourbody that carry an electric charge) acrossmyocardial cell walls creates the electrical eventsthat stimulate the heart muscle to contract The major electrolytes that affect cardiac functionare sodium and potassium 66. The Cardiac Cycle Electrical Events Depolarization is the formation and spread ofelectrical activity in the heart During depolarization, the inside of the cellbecomes more positive Depolarization results in contraction of the heartmuscle During depolarization, the cardiac cells are in arefractory state, which means that they areresistant to additional electrical activity 67. The Cardiac Cycle Electrical Events Repolarization is the return of the cells to theresting or polarized state During repolarization, the inside of the cellbecomes more negatively charged Known as the recovery phase Repolarization results in relaxation of the heartmuscle