Transcript Heart
Chapter 13 Heart Edited by Dr. Ryan Lambert-Bellacov Functions of the Circulatory System • Heart is the pump that circulates blood • Arteries, veins, and capillaries transport the blood • Blood carries oxygen and nutrients to the cells and carries the waste products away • Lymph system functions Major Blood Circuits • Blood leaves the heart through arteries and returns by veins • Blood circulation routes – General or system circulation – Cardiopulmonary circulation • Changes in the composition of circulating blood The Heart • About the size of a closed fist • Weighs about 1 pound • Located in thoracic cavity; apex of heart lies on the diaphragm and points to the left of the body The Heart • After 4 to 5 minutes without blood flow, the brain cells are irreversibly damaged • Can hear the heartbeat through the stethoscope • Cardiac arrest • Cardiopulmonary resuscitation (CPR) Edited by Dr. Ryan Lambert-Bellacov Structure of the Heart • Hollow, muscular, double pump • Pericardium and pericardial fluid • Myocardium – Cardiac muscle tissue • Endocardium- innermost layer of tissue – that lines the chambers of the heart Structure of the Heart • • • • • Superior and inferior vena cava Coronary sinus-collection of veins Pulmonary artery Pulmonary veins Aorta Chambers and Valves • Separated into right and left halves by septum; then each half separated into an upper and lower chamber • Upper chambers – Left and right atria Chambers and Valves • Low chambers – Left and right ventricles • Valves keep blood flow going in one direction Edited by Dr. Ryan Lambert-Bellacov Valves • Atrioventricular valves – Tricuspid valve – Bicuspid or mitral valve • Semilunar valves – Pulmonary semilunar valve – Aortic semilunar valve Edited by Dr. Ryan Lambert-Bellacov Physiology of the Heart • Double pump • Right heart – Deoxygenated blood • Left heart – Oxygenated blood Heart Rate and Cardiac Output • Normal adult rate is between 72 and 80 beats per minute • Stroke volume • Calculating the cardiac output • Exercise increases cardiac output Heart Sounds • Valves make a sound when they close • Called lubb dupp sounds • Lubb – Tricuspid and bicuspid valves (S1) • Dupp – Aortic and pulmonary valves (S2) Conduction System • Electrical impulses cause rhythmic beating of heart • Sinoatrial (SA) node or pacemaker • Atrioventricular (AV) node • Bundle of His • Purkinje fibers ECG or EKG • The electrocardiogram is a device to record the electrical activity of the heart • Systole – Contraction • Diastole – Relaxation ECG or EKG • Positive and negative deflection • P, QRS, and T waves Edited by Dr. Ryan Lambert-Bellacov Prevention of Heart Disease • Heart disease is the leading cause of death – Coronary heart disease • Risk factors • Steps to lower risk or prevent heart disease • Blood cholesterol levels and triglycerides Diagnostic Tests Noninvasive • Angiography-X-ray examination of the – blood vessels or chambers of the heart • • • • Cardiac MRI Coronary calcium scoring/heart scan Echocardiography-sonogram of the heart Electrocardiogram Diagnostic Tests Noninvasive • Exercise stress tests Diagnostic Tests Invasive • Cardiac catheterization • IVUS (intravascular coronary ultrasound) Diagnostic Tests Blood Tests • • • • Arterial blood gases Lipid panel Cardiac enzymes INR/Prothrombin time tests Edited by Dr. Ryan Lambert-Bellacov Effects of Aging • Heart muscle fibers replaced by fibrous tissue • Heart valves increase in thickness • Cardiac output decreases • Changes become more significant when elderly person becomes physically or mentally stressed Diseases of the Heart – Common Symptoms • • • • Arrhythmia Bradycardia Tachycardia Murmurs – Mitral valve prolapse Edited by Dr. Ryan Lambert-Bellacov Diseases of the Coronary Artery • Coronary artery disease (CAD) • Angina pectoris • Myocardial infarction Infectious Diseases of the Heart • Pericarditis • Endocarditis Heart Failure • When the ventricles of the heart are unable to contract effectively and blood pools in the heart • Symptoms depend on which ventricle fails Heart Failure • Left ventricle failure – Dyspnea • Right ventricle failure – Engorgement of organs, edema and ascites Congestive Heart Failure • Similar to heart failure plus edema of the lower extremities and blood backs up into the lungs • Treatment Types of Heart Surgery • Angioplasty • Coronary bypass • Cardiac stents Heart Transplants • Used as last resort • Histocompatibility • Organ rejection Edited by Dr. Ryan Lambert-Bellacov Medical Highlights • Pacemaker • Defibrillator • Heart pumps Edited by Dr. Ryan Lambert-Bellacov