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 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 Semilunar 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 Right ventricle failure Dyspnea 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