Chapter 29
Structure and Function of the
Cardiovascular and Lymphatic
Systems
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
Circulatory System

Heart


Right heart
• Pumps blood through the lungs (pulmonary circulation)
Left heart
• Pumps blood through the systemic circulation
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
2
Circulatory System
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
3
Circulatory System

Heart


Mediastinum
Heart wall
• Pericardium


Parietal and visceral
Pericardial cavity and fluid
• Myocardium
• Endocardium
 Endothelium
• Multifunctional organ
• Essential to normal vascular physiology
• Dysfunction contributes to vascular disease
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
4
The Heart Wall
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
5
The Chambers of the Heart





Right atrium
Left atrium
Right ventricle
Left ventricle
Thickness of each chamber depends on the
pressure or resistance it must overcome to
eject blood
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
6
The Chambers of the Heart
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
7
The Valves of the Heart

Atrioventricular valves



Tricuspid valve
Bicuspid valve
Semilunar valves


Pulmonic semilunar valve
Aortic semilunar valve
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
8
The Valves of the Heart
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
9
The Great Vessels


Superior and inferior venae cavae
Pulmonary artery (trunk)


Right and left pulmonary arteries
Pulmonary veins
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
10
Blood Flow




Cardiac cycle
Diastole
Systole
Phases of the cardiac cycle





Atrial systole
Ventricular systole
Ventricular ejection (semilunar valves open)
Ventricular relaxation (closure of aortic valve)
Ventricular filling (opening of mitral valve)
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
11
Blood Flow
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
12
Normal Intracardiac Pressures





A wave
V wave
X descent
Y descent
C wave
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
13
Normal Intracardiac Pressures
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
14
Normal Intracardiac Pressures
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
15
The Coronary Vessels

Right coronary artery




Conus
Right marginal branch
Posterior descending branch
Left coronary artery


Left anterior descending artery
Circumflex artery
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
16
The Coronary Vessels


Collateral arteries
Diabetes impedes collateral formation


Increased production of antiangiogenic factors
(endostatin and angiostatin)
Presence of an effective collateral system is
protective
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
17
The Coronary Vessels


Coronary capillaries
Coronary veins




Coronary sinus
Great cardiac vein
Posterior vein of the left ventricle
Coronary lymphatic vessels
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
18
The Coronary Vessels
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
19
Structures That Control
Heart Action


Cardiac action potentials
Conduction system

Sinoatrial node (SA)
• Intranodal pathways
 Atrioventricular node (AV)
 Bundle of His (AV bundle)
 Right and left bundle branches
 Purkinje fibers
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
20
Conduction System of the Heart
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
21
Structures That Control
Heart Action


Cardiac excitation
Propagation of cardiac action potentials





Depolarization
Repolarization
Electocardiogram
Automaticity
Rhythmicity
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
22
Electrocardiogram

Sum of all cardiac action potentials


P wave: atrial depolarization
PR interval: time from the onset of atrial activation
to the onset of ventricular activation
• Time necessary to travel from the sinus node through the
atrium, AV node, and His-Purkinje system to activate
ventricular myocardial cells



QRS complex: sum of all ventricular
depolarizations
ST interval: ventricular myocardium depolarized
QT interval: “electrical systole” of the ventricles
• Varies inversely with the heart rate
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
23
Structures That Control
Heart Action

Cardiac innervation



Sympathetic nerves
Parasympathetic nerves
Adrenergic receptor function


α- or β-adrenergic receptors
Norepinephrine or epinephrine
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
24
Adrenergic Receptors




β1 + epinephrine = impact rate and strength
β2 + epinephrine = dilation of arterioles
α1 + norepinephrine = vasoconstriction
α2 + norepinephrine inhibits norepinephrine,
allowing vasodilation
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
25
Myocardial Cells



Nearly identical to skeletal muscle cells
Intercalated disks
Actin, myosin, and the troponin-tropomyosin
complex


Troponin T, I, and C
Myocardial metabolism

Myocardial oxygen consumption
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
26
Myocardial Contraction and
Relaxation
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
27
Cardiac Performance



Preload
Afterload
Frank-Starling law of the heart


End-diastolic volume
Laplace’s law
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
28
Afterload


EDV-ESV = stroke volume, blood moved with
each beat
SV/EDV = EFx (ejection fraction)
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
29
Frank-Starling Law of the Heart

Myocardial stretch determines force of
myocardial contraction


More stretch = increased force of contraction
Major way right and left ventricles maintain
equal minute outputs despite stroke (beat)
output variation
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
30
Laplace’s Law

Contractile force within a chamber depends
on the radius of the chamber and the
thickness of its wall


Smaller chambers and thicker chamber walls =
increased contraction force
In ventricular dilation the force needed to maintain
ventricular pressure lessens available contractile
force
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
31
Cardiac Performance

Heart rate




Cardiovascular control center
• Cardioexcitatory and cardioinhibitory centers
Neural reflexes
• Bainbridge and baroreceptor reflexes
Atrial receptors
Hormones and biochemicals
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
32
Cardiac Performance

Myocardial contractility




Stroke volume
Inotropic agents
Oxygen and carbon dioxide levels
Cardiac output

Volume of blood flowing through either the
systemic or pulmonary circuit in liters per minute
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
33
Cardiac Output
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
34
Systemic Circulation





Arteries
Arterioles
Capillaries
Venules
Veins
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
35
Structure of Blood Vessels




Lumen
Tunica intima
Tunica media
Tunica externa (adventitia)
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
36
Endothelium
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
37
Structure of Blood Vessels
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
38
Factors Affecting Blood Flow


Poiseuille’s law
Pressure


Force exerted on a liquid per unit area
Resistance


Opposition to force
Diameter and length of the blood vessels
contribute to resistance
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
39
Factors Affecting Blood Flow

Neural control of total peripheral resistance




Change in diameter of the vessels
Baroreceptors
Arterial chemoreceptors
Hormones

Epinephrine, norepinephrine, antidiuretic hormone,
renin-angiotensin-aldosterone system, natriuretic
peptides, adrenomedullin, insulin, and others
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
40
Baroreceptor and Chemoreceptors
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
41
Factors Affecting Blood Flow



Velocity
Laminar vs. turbulent flow
Vascular compliance
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
42
Laminar vs. Turbulent Flow
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
43
Regulation of Blood Pressure

Arterial pressure





Mean arterial pressure (MAP)
Effects of cardiac output
Effects of total peripheral resistance
Effects of hyperemia
Effects of hormones
• Epinephrine and norepinephrine
• Antidiuretic hormone, renin-angiotensin-aldosterone
system, and natriuretic peptides
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
44
Regulation of Blood Pressure



Adrenomedullin
Insulin
Venous pressure
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
45
Regulation of Coronary
Circulation



Coronary perfusion pressure
Autoregulation
Autonomic regulation
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
46
Lymphatic System






Special vascular system that picks up excess
fluid and returns it to the bloodstream
Lymphatic fluid
Lymphatic veins and venules
Right lymphatic duct
Thoracic duct
Afferent and efferent lymphatic vessels
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
47
Lymphatic System
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
48
Tests of Cardiovascular Function

Noninvasive assessments





Sensorium of the individual
Mucous membrane color
Manually palpated pulse
Auscultation of heart sounds
Cardiography
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
49
Tests of Cardiovascular Function

Noninvasive assessments





Pulse tracing
Magnetic resonance imaging
Doppler studies
Stress testing
Chest x-ray examinations
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
50
Tests of Cardiovascular Function

Invasive assessments



X-ray films with barium
Nuclear imaging with radiolabeled pharmaceuticals
• Hot spot imaging
• Cold spot imaging
Tomographic studies
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
51
Tests of Cardiovascular Function

Invasive assessments



Atrioventricular bundle electrocardiography
Cardiac catheterization
Coronary angiography
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
52
Aging and the
Cardiovascular System

Arteriosclerosis




Cross-linking of collagen
Increased collagen
Changes in elastin
Atherosclerosis
Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.
53