Download 2011 Cardio - Arlington High School

PowerPoint® Lecture Slide Presentation
by Patty Bostwick-Taylor,
Florence-Darlington Technical College
The
Cardiovascular
System
11
PART A
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The Cardiovascular System
 A closed system of the heart and blood vessels
 The heart pumps blood
 Blood vessels allow blood to circulate to all
parts of the body
 The function of the cardiovascular system is
transportation - it delivers oxygen and nutrients
and removes carbon dioxide and other waste
products
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The Heart
 Location
 Thorax between the lungs in the inferior
mediastinum – medial cavity of the thorax
 Orientation
 Pointed apex directed toward left hip – where
you would place a stethoscope
 Base points toward right shoulder
 About the size of your fist and weighs less than a
pound
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The Heart
Figure 11.1a–b
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The Heart
Figure 11.1c
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The Heart
Figure 11.2a
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The Heart: Coverings
 Pericardium—a double-walled sac
 Fibrous pericardium is loose and superficial
 Serous membrane is deep to the fibrous
pericardium and composed of two layers
 Visceral pericardium
 Next to heart; also known as the
epicardium
 Parietal pericardium
 Outside layer that lines the inner
surface of the fibrous pericardium
 Serous fluid fills the space between the layers
of pericardium
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The Heart: Anatomy
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The Heart: Heart Wall
Figure 11.2b
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The Heart: Heart Wall
 Three layers
 Epicardium - Outside layer
 This layer is the visceral pericardium
 Connective tissue layer
 Myocardium - Middle layer
 Mostly cardiac muscle twisted and whorled into
ringlike arrangement
 The layer that actually contracts
 Called the skeleton of the heart
 Endocardium - Inner layer
 Endothelium that lines heart chambers
 Continuous with blood vessels leaving & entering the
heart
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Homeostatic Imbalance: Pericarditis
 Inflammation of the pericardium
 Results in decrease of serous fluid
 Cause pericardial layers to stick together forming
painful adhesions
 Interferes with heart movement
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The Heart: Heart Wall
Figure 11.2b
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The Heart: Heart Wall
Figure 11.2c
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Review Questions 1
 Where is the location of the heart in the thorax?
 What is the major function of the heart?
 What is the heart enclosed by?
 Name the two layers of the pericardial sac?
 Name the 3 layers of the heart wall
 What is and what causes pericarditis?
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The Heart: Chambers
 Right and left side act as separate pumps
 Four hollow chambers
 2 Atria
 Receiving chambers – not important in pumping activity of
heart
 Blood flows in from veins under low pressure
 Right atrium
 Left atrium
 2 Ventricles
 Discharging chambers – actual pumps of the heart
 Right ventricle
 Left ventricle
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The Heart: Chambers
Figure 11.2c
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Differences in Right and Left Ventricles
Figure 11.4
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The Heart: Septa
 Septum divides the heart longitudinally
 Interventricular septum - Separates the two
ventricles
 Interatrial septum - Separates the two atria
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The Heart: Chambers
Figure 11.2c
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The Heart: Valves
 Allow blood to flow in only one direction to prevent
backflow
 Four valves
 Atrioventricular (AV) valves—between atria
and ventricles
 Bicuspid (mitral) valve (left side of heart)
 Tricuspid valve (right side of heart)
 Anchored in place by chordae tendinae
(“heart strings”)
 Open during heart relaxtion and closed
during ventricular contrations
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Valves
 Semilunar valves—between ventricle and artery
 Pulmonary semilunar valve
 Aortic semilunar valve
 Closed during heart relaxation but open
during ventricular contraction
Notice these valves operate opposite of one
another to force a one-way path of blood
through the heart
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**Homeostatic Imbalance
 Faulty Valves – heart can function with “leaky” valves as long as
damage is not too great
 Incompetent valve – forces heart to pump and repump
same blood because valves don’t close properly & blood
backflows
 Valvular stenosis – valve flaps become stiff often because
of repeated endocarditis (bacterial infection of the
endocardium)
 Forces heart to contract more vigorously increasing
workload
 Faulty valve replaced with synthetic valve,
cryopreserved human valve, or chemically treated
porcine valve (pig heart valve)
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The Heart: Valves
Figure 11.2c
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Operation of the AV valves
Blood returning to
the atria, puts
pressure against
AV valves; the AV
valves are forced
open
AV valves open
Ventricles
(a)
Figure 11.5a, step 1
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Operation of the AV valves
Blood returning to
the atria, puts
pressure against
AV valves; the AV
valves are forced
open
As the ventricles
fill, AV valve flaps
hang limply into
ventricles
AV valves open
Ventricles
(a)
Figure 11.5a, step 2
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Operation of the AV valves
Blood returning to
the atria, puts
pressure against
AV valves; the AV
valves are forced
open
As the ventricles
fill, AV valve flaps
hang limply into
ventricles
Atria contract,
forcing additional
blood into ventricles
AV valves open
Ventricles
(a)
Figure 11.5a, step 3
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Ventricles contract,
forcing blood
against AV valve
flaps
(a)
Figure 11.5a, step 4
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Ventricles contract,
forcing blood
against AV valve
flaps
AV valves close
AV valves closed
(a)
Figure 11.5a, step 5
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Ventricles contract,
forcing blood
against AV valve
flaps
AV valves close
Chordae tendineae
tighten, preventing
valve flaps from
everting into atria
AV valves closed
(a)
Figure 11.5a, step 6
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Operation of the semilunar valves
Aorta
Pulmonary
trunk
As ventricles
contract and
intraventricular
pressure rises,
blood is pushed
up against
semilunar
valves, forcing
them open
Semilunar valve
open
(b)
Figure 11.5b, step 1
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Operation of the semilunar valves
Aorta
Pulmonary
trunk
As ventricles
contract and
intraventricular
pressure rises,
blood is pushed
up against
semilunar
valves, forcing
them open
Semilunar valve
open
(b)
As ventricles
relax, and
intraventricular
pressure falls,
blood flows
back from
arteries, filling
the leaflets of
semilunar
valves and
forcing them
to close
Semilunar valve
closed
Figure 11.5b, step 2
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The Heart: Valves
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Review questions 2
1.What are the receiving chambers of the heart?
the discharging?
2. Why might a thrombus in a coronary artery
cause a sudden death?
3. Why are heart valves important?
4. What is another name for chordae tendinae?
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Systemic and Pulmonary Circulations
 Systemic circulation
 Blood flows from the left side of the heart
through the body tissues and back to the right
side of the heart
 Pulmonary circulation
 Blood flows from the right side of the heart to
the lungs and back to the left side of the heart
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Systemic and Pulmonary Circulations
Figure 11.3
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The Heart: Associated Great Vessels
 Arteries
 Aorta - Leaves left ventricle
 Pulmonary arteries - Leave right ventricle
 Veins
 Superior and inferior venae cavae - Enter right atrium
 Pulmonary veins (four) - Enter left atrium
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The Heart: Associated Great Vessels
Figure 11.2c
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Blood Flow Through the Heart
 Superior and inferior venae cavae dump blood into
the right atrium
 From right atrium, through the tricuspid valve,
blood travels to the right ventricle
 From the right ventricle, blood leaves the heart as
it passes through the pulmonary semilunar valve
into the pulmonary trunk
 Pulmonary trunk splits into right and left
pulmonary arteries that carry blood to the lungs
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Blood Flow Through the Heart
 Oxygen is picked up and carbon dioxide is dropped
off by blood in the lungs
 Oxygen-rich blood returns to the heart through
the four pulmonary veins
 Blood enters the left atrium and travels through
the bicuspid valve into the left ventricle
 From the left ventricle, blood leaves the heart via
the aortic semilunar valve and aorta
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Systemic and Pulmonary Circulations
Figure 11.3
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The Heart: Blood Flow
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Coronary Circulation
 Blood in the heart chambers does not nourish the
myocardium
 The heart has its own nourishing circulatory
system consisting of
 Coronary arteries—branch from the aorta to
supply the heart muscle with oxygenated blood
 Cardiac veins—drain the myocardium of blood
 Coronary sinus—a large vein on the posterior of
the heart, receives blood from cardiac veins
 Blood empties into the right atrium via the
coronary sinus
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** Homeostatic Imbalance
 Angina Pectoris – crushing chest pain caused by
oxygen deprivation of the myocardium
 Infarct – caused by prolonged oxygen deprivation
where heart cells die
 Myocardial infarction – “heart attack” or
“coronary”
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II. Physiology of the Heart
 Intrinsic conduction system (nodal system)
 Heart muscle cells contract, without nerve
impulses, in a regular, continuous way
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The Heart: Conduction System
 Special tissue sets the pace – similar to cross between
muscle & nervous tissue
 Sinoatrial node = SA node (“pacemaker”), is in the
right atrium
 Atrioventricular node = AV node, is at the junction
of the atria and ventricles
 Atrioventricular bundle = AV bundle (bundle of His),
is in the interventricular septum
 Bundle branches are in the interventricular septum
 Purkinje fibers spread within the ventricle wall
muscles
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Heart Contractions
Figure 11.6
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Heart Contractions
 Contraction is initiated by the sinoatrial node (SA
node)
 Sequential stimulation occurs at other
autorhythmic cells
 Force cardiac muscle depolarization in one
direction—from atria to ventricles
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Heart Contractions
 Once SA node starts the heartbeat
 Impulse spreads to the AV node
 Then the atria contract
 At the AV node, the impulse passes through the
AV bundle, bundle branches, and Purkinje fibers
 Blood is ejected from the ventricles to the aorta
and pulmonary trunk as the ventricles contract
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Heart Contractions
Figure 11.6
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Heart Contractions
 Tachycardia—rapid heart rate over 100 beats per
minute
 Bradycardia—slow heart rate less than 60 beats
per minutes
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**Homeostatic Imbalance
 Heart block – when the AV node is damaged
allowing the ventricles to beat at their own slower
rate
 Ischemia – lack of adequate blood supply which
leads to fibrillation- rapid uncoordinated
shudddering of heart muscles
 Pacemaker will need to be inserted to correct
this condition.
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Pacemaker implant
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The Heart: Cardiac Cycle
 In a healthy heart, atria contract simultaneously
 Atria relax, then ventricles contract
 Systole = contraction
 Diastole = relaxation
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Filling Heart Chambers: Cardiac Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Isovolumetric
Ventricular
contraction phase ejection phase
Isovolumetric
relaxation
Ventricular systole
(atria in diastole)
Early diastole
Figure 11.7
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Filling Heart Chambers: Cardiac Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Mid-to-late diastole
(ventricular filling)
Figure 11.7, step 1a
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Filling Heart Chambers: Cardiac Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Figure 11.7, step 1b
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Filling Heart Chambers: Cardiac Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Isovolumetric
contraction phase
Ventricular systole
(atria in diastole)
Figure 11.7, step 2a
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Filling Heart Chambers: Cardiac Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Isovolumetric
Ventricular
contraction phase ejection phase
Ventricular systole
(atria in diastole)
Figure 11.7, step 2b
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Filling Heart Chambers: Cardiac Cycle
Left atrium
Right atrium
Left ventricle
Right ventricle
Ventricular
filling
Atrial
contraction
Mid-to-late diastole
(ventricular filling)
Isovolumetric
Ventricular
contraction phase ejection phase
Isovolumetric
relaxation
Ventricular systole
(atria in diastole)
Early diastole
Figure 11.7, step 3
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The Heart: Cardiac Cycle
 Cardiac cycle—events of one complete heart beat
 Mid-to-late diastole—blood flows from atria
into ventricles
 Ventricular systole—blood pressure builds
before ventricle contracts, pushing out blood
 Early diastole—atria finish refilling, ventricular
pressure is low
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Heart Sounds
 When using a stethoscope you hear two distinct
sounds in a cardiac cycle.
 These heart sounds are described by two syllables
“lub” and “dup”
 The “lub” is caused by the closing of the AV valves
(bicuspid and tricuspid)
 The “dup” occurs when the semilunar valves close.
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** Homeostatic Imbalance - Murmurs
 Murmur – abnormal or unusual heart sounds
 Fairly common in young children (and some
elderly people) with perfectly healthy hearts
probably due to thin heart walls.
 Outside of these groups a murmur may indicate
a valve problem.
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The Heart: Regulation of Heart Rate
 Increased heart rate
 Sympathetic nervous system
 Crisis stressors (physical or emotional
trauma, high body temp.)
 Low blood pressure
 Hormones can also increase heart rate
 Epinephrine
 Thyroxine
 Exercise – working muscles generate heat
which increases heart rate by boosting
metabolism
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The Heart: Regulation of Heart Rate
 Decreased heart rate
 Parasympathetic nervous system slow and
steady the heart giving it time to rest.
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Cardiac Output Regulation
Figure 11.8
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** Homeostatic Imbalance
 Congestive heart failure – when the pumping
efficiency of the heart is depressed so that
circulation is inadequate to meet tissue needs.
 A progressive condition that may be caused by
coronary atherosclerosis (blockage of coronary
vessels with fatty buildup), persistent high
blood pressure or multiple myocardial
infarctions
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Congestive Heart Failure (CHF)
 Each side can fail independently
 If the left side fails it is pulmonary
congestion because the right side continues
to send blood to the lungs but the left side
can not discharge blood into systemic
circuclation
 Lungs become swollen with blood, pressure
increases and fluid leaks into lung tissue
causing pulmonary edema
 If untreated the patient suffocates
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Congestive Heart Failure (CHF)
 If the right side fails peripheral
congestion occurs as blood backs up in the
systemic circulation
 Edema is most noticeable in distal parts of
the body; feet, ankles, and fingers become
swollen and puffy
 Failure of one side puts a greater strain on the
other side and eventually the whole heart fails
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