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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
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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
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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
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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
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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