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Chapter 13. Heart . 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.
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Chapter 13 Heart
Functions of theCirculatory 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)
Structure of the Heart • Hollow, muscular, double pump • Pericardium and pericardial fluid • Myocardium • Cardiac muscle tissue • Endocardium
Structure of the Heart • Superior and inferior vena cava • Coronary sinus • 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
Valves • Atrioventricular valves • Tricuspid valve • Bicuspid or mitral valve • Semilunar valves • Pulmonary semilunar valve • Aortic semilunar valve
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
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 • Cardiac MRI • Coronary calcium scoring/heart scan • Echocardiography • Electrocardiogram
Diagnostic Tests Noninvasive • Exercise stress tests • Holter monitor • MUGA • Transesophageal echocardiography
Diagnostic Tests Invasive • Cardiac catheterization • IVUS (intravascular coronary ultrasound)
Diagnostic Tests Blood Tests • Arterial blood gases • BNP • Lipid panel • Cardiac enzymes • INR/Prothrombin time tests
Animation – The Heart Click Here to play Heart animation
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
Diseases of the Coronary Artery • Coronary artery disease (CAD) • Angina pectoris • Myocardial infarction
Infectious Diseases of the Heart • Pericarditis • Myocarditis • Endocarditis • Rheumatic heart disease
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
Rhythm/Conduction Defects • Heart block • First-degree block • Second-degree block • Third-degree block or complete heart block • Premature contractions • PACs • PVCs • Fibrillation
Types of Heart Surgery • Angioplasty • Coronary bypass • Cardiac stents • Transmyocardial laser revascularization
Heart Transplants • Used as last resort • Histocompatibility • Organ rejection
Medical Highlights • Pacemaker • Cardiac resynchronization therapy • Defibrillator • Heart pumps