Download 1 The Cardiovascular System

Essentials of Human Anatomy & Physiology
INTERESTING FACTS ABOUT THE HEART
...
Seventh Edition
Elaine N. Marieb
• http://www.webmd.com/heart/features/amazingfacts-about-heart-health-and-heart-disease_
Chapter 11
The Cardiovascular System
Slides 11.1 – 11.19
Lecture Slides in PowerPoint by Jerry L. Cook
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The Cardiovascular System
The Heart
• A closed system of the heart and blood
vessels
• Location
• The heart pumps blood
• Thorax between the lungs
• Blood vessels allow blood to circulate to all
parts of the body
• Pointed apex directed toward left hip
• The function of the cardiovascular
system is to deliver oxygen and
nutrients and to remove carbon dioxide
and other waste products
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.1
The Heart
• About the size of your fist
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Slide 11.2a
The Heart: Coverings
• Pericardium – a double serous
membrane
• Visceral pericardium
• Next to heart
• Parietal pericardium
• Outside layer
• Serous fluid fills the space between the
layers of pericardium
Figure 11.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.2b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.3
1
Heart Covering
The Heart: Heart Wall
• Pericardial physiology
• Three layers
• Protects and anchors heart
• Epicardium
• Outside layer
• This layer is the parietal pericardium
• Connective tissue layer
• Prevents overfilling
• Myocardium
• Middle layer
• Mostly cardiac muscle
• Endocardium
• Inner layer
• Endothelium
Figure 19.2
External Heart Anatomy
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.4
The Heart: Chambers
• Right and left side act as separate pumps
• Four chambers
• Atria
• Receiving chambers
• Right atrium
• Left atrium
• Ventricles
• Discharging chambers
• Right ventricle
• Left ventricle
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 11.2a
Slide 11.5
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Slide 11.6
Atria of the Heart
Ventricles of the Heart
• Atria are the receiving chambers of the heart
• Each atrium has a protruding auricle
• Ventricles are the discharging chambers of the
heart
• Pectinate muscles mark atrial walls
• Papillary muscles and trabeculae carneae muscles
mark ventricular walls
• Blood enters right atria from superior and inferior
venae cavae and coronary sinus
• Right ventricle pumps blood into the pulmonary
trunk
• Blood enters left atria from pulmonary veins
• Left ventricle pumps blood into the aorta
2
Blood Circulation
Pathway of Blood through the Heart and Lungs
• Right atrium tricuspid valve right ventricle
• Right ventricle pulmonary semilunar valve pulmonary arteries lungs
• Lungs pulmonary veins left atrium
• Left atrium bicuspid valve left ventricle
• Left ventricle aortic semilunar valve aorta
• Aorta systemic circulation
Figure 11.3
Slide 11.7
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The Heart: Valves
Gross Anatomy of Heart: Frontal Section
• Allow blood to flow in only one direction
• Four valves
• Atrioventricular valves – between atria and
ventricles
• Bicuspid valve (left)
• Tricuspid valve (right)
• Semilunar valves between ventricle and
artery
• Pulmonary semilunar valve
• Aortic semilunar valve
Figure 19.4e
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.8
The Heart: Valves
Heart Valves
• Valves open as blood is pumped
through
• Held in place by chordae tendineae
(“heart strings”)
• Close to prevent backflow
Figure 19.9
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.9
3
The Heart: Associated Great Vessels
Operation of Heart Valves
• Aorta
• Leaves left ventricle
• Pulmonary arteries
• Leave right ventricle
• Vena cava
• Enters right atrium
• Pulmonary veins (four)
• Enter left atrium
Figure 11.4
Slide 11.10
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Coronary Circulation
Slide 11.11
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The Heart: Conduction System
• Blood in the heart chambers does not
nourish the myocardium
• Intrinsic conduction system
(nodal system)
• The heart has its own nourishing
circulatory system
• Heart muscle cells contract, without nerve
impulses, in a regular, continuous way
• Coronary arteries
• Cardiac veins
• Blood empties into the right atrium via the
coronary sinus
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Slide 11.12
The Heart: Conduction System
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Slide 11.13a
Heart Contractions
• Special tissue sets the pace
• Contraction is initiated by the sinoatrial
node
• Sinoatrial node
• Pacemaker
• Sequential stimulation occurs at other
autorhythmic cells
• Atrioventricular node
• Atrioventricular bundle
• Bundle branches
• Purkinje fibers
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Slide 11.13b
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Slide 11.14a
4
Heart Physiology: Sequence of Excitation
Heart Physiology: Sequence of Excitation
• AV bundle splits into two pathways in the
interventricular septum (bundle branches)
• Sinoatrial (SA) node generates impulses about 75
times/minute
• Atrioventricular (AV) node delays the impulse
approximately 0.1 second
• Bundle branches carry the impulse toward the apex of
the heart
• Impulse passes from atria to ventricles via the
atrioventricular bundle (bundle of His)
• Purkinje fibers carry the impulse to the heart apex and
ventricular walls
Heart Contractions
• http://www.youtube.com/watch?v=te_SY3MeWy
s
Figure 11.5
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Slide 11.14b
Electrocardiography
Electrocardiography
• Electrical activity is recorded by electrocardiogram (ECG)
• P wave corresponds to depolarization of atria
• QRS complex corresponds to ventricular depolarization
• T wave corresponds to ventricular repolarization
• Atrial repolarization record is masked by the larger QRS
complex
Figure 19.16
5
Filling of Heart Chambers –
the Cardiac Cycle
• http://www.youtube.com/watch?v=jLTdgrhpDCg
• http://www.youtube.com/watch?v=r32VObKw0g
Y
Figure 11.6
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 11.15
The Heart: Cardiac Cycle
The Heart: Cardiac Cycle
• Cardiac cycle – events of one complete
heart beat
• Atria contract simultaneously
• Mid-to-late diastole – blood flows into
ventricles
• Atria relax, then ventricles contract
• Systole = contraction
• Ventricular systole – blood pressure builds
before ventricle contracts, pushing out
blood
• Diastole = relaxation
• Early diastole – atria finish re-filling,
ventricular pressure is low
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Slide 11.16
The Heart: Cardiac Output
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Slide 11.17
Cardiac Output Regulation
• Cardiac output (CO)
• Amount of blood pumped by each side of
the heart in one minute
• CO = (heart rate [HR]) x (stroke volume
[SV])
• Stroke volume
• Volume of blood pumped by each ventricle
in one contraction
Figure 11.7
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Slide 11.18
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Slide 11.19
6