Transcript Slide 1 - Cengage

Chapter 13
Heart
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Functions of the
Circulatory System
• The heart is the pump that circulates blood
to all parts of the body
• Arteries, veins, and capillaries transport the
blood
• Blood carries oxygen and nutrients to the
cells and carries waste products away
• Lymph system returns excess fluid from the
tissues the circulation
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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
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The Heart
• About 5 inches long and 3.5 inches wide
• Weighs about 1 pound
• Located in the thoracic cavity; the apex of
the heart lies on the diaphragm and points to
the left of the body
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Figure 13-1 The heart is located in the thoracic cavity between the
lungs
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The Heart
• After 4 to 5 minutes without blood flow,
brain cells are irreversibly damaged
• Can hear the heartbeat through a
stethoscope
• Cardiac arrest
• Cardiopulmonary resuscitation (CPR)
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Structure of the Heart (1 of 2)
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Hollow, muscular, double pump
Pericardium and pericardial fluid
Epicardium
Myocardium
– Cardiac muscle tissue
• Endocardium
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Structure of the Heart (2 of 2)
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Superior and inferior vena cava
Coronary sinus
Pulmonary artery
Pulmonary veins
Aorta
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Figure 13-2 Anterior external view of the heart
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Figure 13-3 Anterior cross-sectional view of the heart
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Chambers and Valves (1 of 2)
• Separated into right and left halves by the
septum; then each half separated into an
upper and lower chamber
• Upper chambers
– Left and right atria
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Chambers and Valves (2 of 2)
• Lower chambers
– Left and right ventricles
• Valves keep blood flowing in one
direction
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Valves
• Atrioventricular valves
– Tricuspid valve (separates the right atria and right ventricle)
– Bicuspid or mitral valve (separates the left atria and left
ventricle)
• Semilunar valves
– Pulmonary semilunar valve (opening of the pulmonary
arteries)
– Aortic semilunar valve (opening of the aorta)
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Physiology of the Heart
• Double pump
• Right heart
– Deoxygenated blood
• Left heart
– Oxygenated blood
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Heart Rate and Cardiac Output
• Normal adult rate is between 72 and 80
beats per minute
• Cardiac output=stroke volume x heart rate
• Calculating the cardiac output
• Exercise increases cardiac output
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Heart Sounds
• Valves make sounds when they close
• Called lubb dupp sounds
• Lubb
– Tricuspid and bicuspid valves (S1)
• Dupp
– Aortic and pulmonary valves (S2)
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Conduction System
• Electrical impulses cause rhythmic beating
of the heart
• Sinoatrial (SA) node or pacemaker
• Atrioventricular (AV) node
• Bundle of His
• Purkinje fibers
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Figure 13-7 An electrical impulse from the SA node travels to the
AV node and causes the ventricle to contract
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ECG or EKG (1 of 2)
• The electrocardiogram is a device to record
the electrical activity of the heart
• Systole
– Contraction
• Diastole
– Relaxation
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ECG or EKG (2 of 2)
• Positive and negative deflection
• P, QRS, and T waves
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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
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Prevention of Heart Disease
• Heart disease is the leading cause of death
for both men and women in the US
– Coronary heart disease
• Risk factors
• Steps to lower risk or prevent heart disease
• Blood cholesterol levels and triglycerides
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Diagnostic Tests – Noninvasive
(1 of 2)
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Angiography
Cardiac MRI
Coronary calcium scoring/heart scan
Echocardiography
Electrocardiogram
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Diagnostic Tests – Noninvasive
(2 of 2)
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Exercise stress tests
Holter monitor
MUGA (multiple gated acquisition scan)
Nuclear perfusion
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Diagnostic Tests – Invasive
• Cardiac catheterization
• IVUS (intravascular coronary ultrasound)
• TEE
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Diagnostic Tests – Blood Tests
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Arterial blood gases
BNP
Lipid panel
C-reactive protein
Cardiac Troponin T
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Diseases of the Heart –
Common Symptoms
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Arrhythmia
Bradycardia
Tachycardia
Murmurs
Mitral valve prolapse
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Diseases of the Coronary Artery
• Coronary artery disease (CAD)
• Angina pectoris
• Myocardial infarction
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Infectious Diseases of the Heart
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Pericarditis
Myocarditis
Endocarditis
Rheumatic heart disease
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Heart Failure (1 of 2)
• When the ventricles of the heart are unable
to contract effectively and blood pools in
the heart
• Symptoms depend on which ventricle fails
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Heart Failure (2 of 2)
• Left ventricle failure
– Dyspnea (shortness of breath)
• Right ventricle failure
– Engorgement of organs, edema of the legs and feet, and ascites
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Congestive Heart Failure
• Similar to heart failure
• Left-sided failure – pulmonary edema
• Right-sided failure – fluid buildup
throughout body
• Treatment
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Rhythm/Conduction Defects
• Heart block
– First-degree block
– Second-degree block
– Third-degree block or complete heart block
• Premature contractions
– Atrial fibrillation
– PVCs
– Ventricular fibrillation
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Types of Heart Surgery
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Angioplasty
Cardiac stents
Coronary bypass
Transmyocardial laser revascularization
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Heart Transplants
• Used as a last resort
• Histocompatibility
• Organ rejection
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Medical Highlights
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Pacemaker
Cardiac resynchronization therapy
Defibrillator
Heart pumps
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