ST120 Unit 2:
The Heart
Concorde Career College, Portland
The Heart
Objectives:
 Evaluate the anatomic development of the heart
 Describe the basic anatomy of the heart, including coverings,
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wall, chambers, and valves
Trace the flow of blood into, through, and out of the heart
Evaluate myocardial infarction
Describe the conduction system of the heart
Describe basic cardiac dysrhythmias and electrocardiogram
elements
The Heart: Part of the Cardiovascular System
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Cardiovascular
(Circulatory)
System
Blood
Heart
Arteries
Veins
Capillaries
Cardiovascular System
Cardiovascular
Pertaining to the heart and
blood vessels.
Cardiovascular System
 Heart
 the pump
 Peripheral vascular system
 arteries – carry blood AWAY from the heart
 Veins – carry blood TOWARD the heart
 capillaries – tiny webs that connect the arteries and veins
peripherally; gas exchange takes place called internal respirations
 The lymphatic system also part of the circulatory system
Function of the Blood Circulatory System-Simply→ Transportation
 Blood Transports
 Hormones
 Enzymes
 Oxygen
 Carbon dioxide
 Carries nutrients (from various organs) and oxygen (from the lungs)
to the body’s cells for use, which creates waste
 The waste (includes carbon dioxide) is carried from the cells to the
excretory organs. Example-Lungs expires carbon dioxide
Cardiovascular System
The Heart
Cardiovascular System
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General Information
Located in the
mediastinum
Slightly bigger than a fist
Contracts approximately
72 times per minute
2/3 of the heart is located
toward the left of the
thoracic cavity
Cardiovascular System
Function of the Heart
 Pump
 Systole (contraction)
 Diastole (relaxation)
Coverings of the Heart
 Pericardium – loose fitting sac that covers the entire heart
 Serous pericardium – inside the pericardium; composed of
two layers
 Parietal layer- lines the inside of the pericardium
 Visceral layer- thin layer that covers the heart
 Pericardial cavity – space located between the Parietal layer
and the Visceral layer; contains pericardial fluid to reduce
friction
Pericardium
Heart Anatomy
 Epicardium is the outer layer of the heart wall
 Each chamber is lined by a thin layer of tissue called the endocardium
 The wall of each chamber is composed of cardiac muscle tissue called the
myocardium
Cardiovascular System
Chambers of the Heart
 Atria (receiving
chambers)
 Ventricles (pumping
chambers)
 Separated into right and
left sides by the septum
HEART CHAMBERS
 UPPER CHAMBERS – RIGHT AND LEFT ATRIA which
receives oxygen poor blood returning from lungs and body
 LOWER CHAMBERS – RIGHT AND LEFT VENTICLES
moves oxygen rich blood into arteries
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Cardiovascular System
Heart Valves
 Tricuspid (right
atrioventricular)
 Bicuspid (mitral or left
atrioventricular)
 Pulmonary (semilunar)
 Aortic (semilunar)
HEART VALVES
 why do we need heart valves?
 To keep the blood flowing one direction
 The valve that separates the right atrium from the right
ventricle is called the?
 TRICUSPIDVALVE
 The valve that separates the left atrium from the left
ventricle is called the?
 BICUSPIDVALVE or MITRAL
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Heart Valves
 SL or semilunar valves located between the two ventricles and the
arteries that carry the blood away from the heart
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Heart Valves
 Pulmonary semilunar valve is located at the beginning of the pulmonary artery
that allows blood to flow from the right ventricle to the lungs
 Aortic semilunar valve is located at the beginning of the aorta and allows blood to
flow out of the left ventricle into the aorta
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Cardiovascular System
Chordae Tendineae
 Stabilize valve flaps to
promote one way blood
flow
Cardiovascular System
Myocardial Blood
Supply
 Right coronary artery
 Left coronary artery
 Circumflex artery
 Right marginal branch
 Anterior and posterior
interventricular arteries
Coronary arteries and Coronary veins
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Blood Flow through the Heart
 The right side of the heart receives oxygen-poor blood from the veins
•Blood enters right atrium through the superior vena cava and
the inferior vena cava
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Blood Flow through the Heart
 When the heart “beats”, first the atria contract simultaneously
(atrial systole)
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Blood Flow through the Heart
 Then the ventricles fill with blood and they contract together
 When the ventricles contract, blood in the right ventricle is pumped
through the pulmonary semilunar valve into the pulmonary artery and
to the lungs, where it is oxygenated
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Blood Flow Through the Heart
 Oxygenated blood returns to the left atrium through 4 pulmonary
veins
 It then passes through the left AV or bicuspid valve to the left ventricle
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Blood Flow Through the Heart
 From the left ventricle, the blood is pumped out through the aortic
semilunar valve to the aorta
 From the aorta to the rest of the body!
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Conduction System
 Electrical impulses that signal the heart to beat
 All cardiac muscle fibers in each region of the heart are
electrically linked together!
 Intercalated disks are electrical connectors that join the
muscle fibers
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Cardiovascular System
Conduction System
 Sinoatrial (SA) node
 Atrioventricular (AV)
node
 Bundle of His
 Right and left bundle
branches
 Purkinje fibers
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Cardiac Cycle
 Each complete heartbeat is called a cardiac cycle
 Consists of alternating systole (contraction) and diastole
(relaxation) of atria and ventricles
 Stroke volume is the volume of blood ejected from the
ventricles during each beat
 Cardiac output is the volume of blood ejected from the left
ventricle into the aorta
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Pathology
 Coronary Atherosclerotic Heart Disease - a condition in which
fatty material collects along the walls of arteries. This fatty
material thickens, hardens (forms calcium deposits), and may
eventually block the arteries; endothelial cell dysfunction
 Myocardial Ischemia - (reduced blood supply) of the heart muscle,
usually due to the blockage caused by Coronary Atherosclerosis
 Angina pectoris – chest pain due to Myocardial Ischemia
 Myocardial Infarction (MI) – death of heart muscle tissue from
Myocardial Ischemia, which leads to sudden cardiac death
Pathology
 Ventricular fibrillation – major dysrhythmia of the ventricles. They
flutter without coordination which results in lack of blood
pumped out of the heart
 Heart block – a disease in the electrical system of the heart
 Asystole – cardiac arrest
 Myocardial rupture – blood escaping the ventricles and entering
the pericardial sac; can result in cardiac tamponade
 Cardiac aneurysm – ballooning of the ventricular wall resulting in
increases pressure in the ventricles
Coronary Atherosclerotic Heart Disease
Coronary Atherosclerotic Heart Disease
Coronary Atherosclerotic Heart Disease
Treatments
 Preformed in the Cardiac Catheterization lab (Cath Lab)
 Percutaneous Transluminal Coronary Angioplasty (PTCA)
 Coronary Stent
 Intra-coronary Thrombolysis
Coronary Stent - A Treatment for Coronary
Atherosclerotic Heart Disease
Percutaneous Transluminal Coronary
Angioplasty (PTCA)
Treatments
 Preformed in the Heart Room in the OR Suite
 Coronary Artery Bypass Grafting (CABG)
 Permanent pacemaker
Surgical Treatment : Coronary Artery
Bypass Grafting (CABG)
Possible Grafts for CABG
1. Saphenous vein
2. Internal thoracic arteries (mammary)
3. Radial Artery
Saphenous Vein Harvesting
Postoperative Healing
Endoscopic Saphenous Harvesting
Mammary Artery Harvesting
Internal Mammary Artery
Radial Artery Harvesting
Cardiopulmonary Bypass
Identify the
locations of the
tube insertions
into the
circulatory
system
Permanent Pacemaker
Dysrhythmias
 Sinus Dysrhythmia – most common; related to vagal
nerve impulses to the SA node; benign
 Sinus Tachycardia – heart rate of 100 beats or more per
minute
 Sinus Bradycardia - heart rate of 60 beats or less per
minute
Atria Dysrhythmias
Dysrhythmias originating in the atria:
 Premature atrial beat – often associated with stress or
consumption of caffeine or nicotine
 Atrial tachycardia – atrial rate of 150-250 beats per minute;
usually benign
 Atrial flutter - atrial rate of 250-350 beats per minute; can
result in increased ventricular rate and decrease in oxygen
 Atrial fibrillation - atrial rate of 350-600 beats per minute;
results in increased ventricular rate and decrease in oxygen
Ventricular Dysrhythmias
 Benign PVC’s – less than 5 per hour; absence of heart disease
 Complex PVC’s – greater than 10-30 per hour; with or
without heart disease
 Malignant PVC’s – same as complex except with left
ventricular dysfunction
 Ventricular tachycardia – 140-250 beats per minute
 Ventricular flutter – regular contractions but at a fast rate of
250-350 per minute
Electrocardiogram
 ECG or EKG
 Electrical signals can be picked up form the body surface and
transformed into visible tracings by an instrument called an
electrocardiograph
 The electrocardiogram is the graphic record of the heart’s
electrical activity
ECG
 3 characteristic deflections or waves
 P wave – depolarization (triggers contraction) of atria
 QRS complex - depolarization (triggers contraction) of
ventricles
 T wave - repolarization of ventricles
Cardiothoracic Procedures
Features of the ECG Paper
ECG Electrical Correlation
Electrocardiograph
(Normal Sinus Rhythm)
Sinus Rhythm
Occasional (Incidental) PVC
Bigeminy
(PVC Every Other Beat)
Ventricular Fibrillation
(V Fib)
Premature Atrial Contraction
(PAC)
Atrial Fibrillation
Asystole