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Chapter 18:
Cardiovascular System:
The Heart
Dr. Norman E. Shumway – performed the first heart
transplant in the United States in 1968. The 54-year-old
recipient, whose heart had been damaged by virus infection,
survived 15 days following surgery.
Figure 18.3: The circular and spiral arrangement of cardiac muscle bundles in the myocardium of the heart, p. 680.
Cardiac
muscle
bundles
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.4a: Gross anatomy of the heart, p. 681.
Aortic arch
(fat covered)
Pulmonary trunk
Right atrium
Left auricle of
left atrium
Anterior
interventricular
artery
Right ventricle
(a)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Apex of heart
(left ventricle)
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.4b: Gross anatomy of the heart, p. 681.
Brachiocephalic
trunk
Superior
vena cava
Left common
carotid artery
Left
subclavian artery
Aortic arch
Right
pulmonary artery
Ligamentum
arteriosum
Left pulmonary artery
Ascending
aorta
Pulmonary trunk
Right
pulmonary veins
Right atrium
Right coronary
artery (in coronary
sulcus)
Anterior
cardiac vein
Right ventricle
Marginal artery
Small cardiac vein
Inferior
vena cava
(b)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Left pulmonary veins
Left atrium
Auricle
Circumflex
artery
Left coronary
artery (in coronary
sulcus)
Left ventricle
Great cardiac vein
Anterior
interventricular artery
(in anterior
interventricular sulcus)
Apex
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.4d: Gross anatomy of the heart, p. 682.
Aorta
Left
pulmonary artery
Left
pulmonary veins
Auricle
of left atrium
Left atrium
Superior
vena cava
Right
pulmonary artery
Right
pulmonary veins
Right atrium
Great cardiac vein
Inferior
vena cava
Posterior vein
of left ventricle
Right coronary
artery (in coronary
sulcus)
Coronary sinus
Apex
Posterior
interventricular artery
(in posterior
interventricular sulcus)
Middle cardiac vein
(d)
Right ventricle
Left ventricle
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.4e: Gross anatomy of the heart, p. 683.
Aorta
Superior vena cava
Right
pulmonary artery
Pulmonary trunk
Right atrium
Right
pulmonary veins
Fossa
ovalis
Pectinate
muscles
Tricuspid
valve
Right ventricle
Chordae
tendineae
Trabeculae
carneae
Inferior
vena cava
(e)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Left
pulmonary artery
Left atrium
Left
pulmonary veins
Mitral
(bicuspid) valve
Aortic
valve
Pulmonary
valve
Left ventricle
Papillary
muscle
Interventricular
septum
Myocardium
Visceral
pericardium
Endocardium
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.5: The systemic and pulmonary circuits, p. 684.
Capillary beds
of lungs where
gas exchange
occurs
Pulmonary Circuit
Pulmonary
arteries
Venae
cavae
Pulmonary
veins
Aorta and
branches
Left
atrium
Left
Right
ventricle
atrium
Heart
Right
ventricle
Systemic Circuit
Key:
= Oxygen-rich,
CO2-poor blood
= Oxygen-poor,
CO2-rich blood
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Capillary
beds of all
body tissues
where gas
exchange
occurs
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.6: Anatomical differences in right and left ventricles, p. 685.
Left
ventricle
Right
ventricle
Muscular
interventricular
septum
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.7: Coronary circulation, p. 685.
Aorta
Pulmonary
trunk
Left
coronary
artery
Superior
Left atrium vena cava
Superior
vena cava
Anastomosis
(junction of
vessels)
Right
coronary
artery
Circumflex
artery
Right
ventricle
Left
ventricle
Right
atrium
Marginal
artery
(a)
Posterior
Anterior
interventricular interventricular
artery
artery
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Great
cardiac
vein
Anterior
cardiac
veins
Coronary
sinus
Small cardiac vein
Middle cardiac vein
(b)
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.11: Microscopic anatomy of cardiac muscle, p. 690.
Intercalated discs
Nucleus
Cardiac muscle cell
Desmosome
Desmosome
Gap junctions
(a)
Mitochondrion
Nucleus
Cardiac muscle cell
Sarcoplasmic
reticulum
T tubule
Nucleus
Intercalated disc
Sarcolemma
(b)
Z disc
Sarcolemma
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
I band A band I band
Mitochondrion
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
William Einthoven – invented the electrocardiograph and
awarded the nobel prize in 1924
Figure 18.16: An electrocardiogram tracing (lead I), p. 696.
QRS complex
R
Sinoatrial
node
Ventricular
depolarization
Atrioventricular
node
Atrial
depolarization
Ventricular
repolarization
T
P
Q
P-Q
Interval
Time (s)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
0
S-T
S Segment
0.2
0.4
Q-T
Interval
0.6
0.8
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.17: The sequence of excitation of the heart related to the deflection waves of an ECG tracing, p. 696.
SA node generates impulse;
atrial excitation begins
SA node
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Impulse delayed
at AV node
AV node
Impulse passes to
heart apex; ventricular
excitation begins
Bundle
branches
Ventricular excitation
complete
Purkinje
fibers
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.19: Areas of the thoracic surface where the heart sounds can be best detected, p. 697.
Sounds of aortic valve are
heard in 2nd intercostal space at
right sternal margin.
Sounds of pulmonary valve
are heard in 2nd intercostal
space at left sternal margin.
Sounds of mitral valve are
heard over heart apex, in 5th
intercostal space in line with
middle of clavicle.
Sounds of tricuspid valve are typically heard in
right sternal margin of 5th intercostal space;
variations include over sternum or over left
sternal margin in 5th intercostal space.
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.24: Development of the human heart during week 4, p. 705.
Endothelial
tubes begin
to fuse
Ductus
arteriosus
Pulmonary
trunk
Foramen
ovale
Aorta
Superior
vena cava
Arterial end
Arterial end
4a
4
Tubular
heart
3
2
1
Atrium
Inferior
vena cava
Ventricle
Venous end
(a)
Ventricle
Ventricle
(b)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
(c)
Venous end
(e)
(d) Heart twists
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Figure 18.25: Three examples of congenital heart defects, p. 708.
Narrowed
aorta
Occurs in
about 1 in every
500 births
Occurs in
about 1 in every
1500 births
Occurs in
about 1 in every
2000 births
(a) Ventricular septal defect.
(b) Coarctation of the aorta.
(c) Tetralogy of Fallot. Multiple defects
The superior part of the interA part of the aorta is narrowed,
(tetra = four): Pulmonary trunk too
ventricular septum fails to form;
increasing the workload on
narrow and pulmonary valve
thus, blood mixes between
the left ventricle.
stenosed, resulting in a hypertrophied
the two ventricles, but because
right ventricle; ventricular septal
the left ventricle is stronger,
defect; aorta opens from both
more blood is shunted from
ventricles; wall of right ventricle
left to right.
thickened from overwork.
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.