Download Chapter 12: Heart

Fig. 12.2
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CO2
O2
Tissue
capillaries
Circulation to
tissues of head
Lung
CO2
Pulmonary
circulation
(to lungs)
Lung
capillaries
O2
Left side
of heart
Right side of heart
Circulation to
tissues of
lower body
Tissue
capillaries
CO2
O2
Systemic
circulation
(to body)
Fig. 12.10-1
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Aortic arch
Superior
vena cava
Branches of
right pulmonary
arteries
Left pulmonary artery
Branches of left
pulmonary arteries
Pulmonary trunk
Pulmonary veins
Aortic semilunar
valve
Pulmonary
veins
Pulmonary semilunar
valve
Right atrium
Tricuspid valve
Papillary muscles
Right ventricle
Inferior
(a) vena cava
Left atrium
Bicuspid valve
Left ventricle
Interventricular septum
Fig. 12.5-1
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Aortic arch
Left pulmonary artery
Superior vena cava
Branches of left
pulmonary artery
Branches of right
pulmonary artery
Pulmonary trunk
Left pulmonary veins
Right pulmonary veins
Left atrium
Right atrium
Great cardiac vein
(in anterior interventricular sulcus)
Coronary sulcus
Right coronary artery
Anterior interventricular artery
(in anterior interventricular sulcus)
Right ventricle
Left ventricle
Inferior vena cava
(a)
Anterior view
Fig. 12.13
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Branching
muscle fibers
Intercalated disks
T tubule
Sarcoplasmic
reticulum
Nucleus of cardiac
muscle cell
Striations
Sarcomere
LM 400x
Mitochondrion
Sarcolemma (cell membrane)
Myofibrils
Connective tissue
(a)
(b)
b: © Ed Reschke
Fig. 12.11
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Aortic arch
Aortic arch
Superior
vena cava
Pulmonary
trunk
Aortic
semilunar
valve
Left coronary
artery
Pulmonary
trunk
Left atrium
Left atrium
Right
atrium
Circumflex
artery
Right
coronary
artery
Left marginal
artery
Anterior
interventricular
artery
Posterior
interventricular
artery
Right
marginal
artery
Left ventricle
Right
atrium
Posterior vein
of left ventricle
Into
right
atrium
Middle
cardiac vein
Anterior view
Small
cardiac
vein
(b)
Coronary
sinus
Great
cardiac
vein
Left
ventricle
Right ventricle
Right ventricle
(a)
Superior
vena cava
Anterior view
Fig. 12.14
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Skeletal Muscle
Cardiac Muscle
Repolarization
phase
2
0
Plateau
phase
0
(mV)
(mV)
1
2
1
Depolarization
phase
Depolarization
phase
Repolarization
phase
–85
–85
1
2
1
Time (ms)
(a)
3
1 Depolarization phase
• Na+ channels open.
• K+ channels begin to open.
2 Repolarization phase
• Na+ channels close.
• K+ channels continue to open, causing
repolarization.
• K+ channels close at the end of
repolarization and return the membrane
potential to its resting value.
2
Time (ms)
(b)
1 Depolarization phase
• Na+ channels open.
• Ca2+ channels open.
2 Plateau phase
• Na+ channels close.
• Some K+ channels open, causing
repolarization.
• Ca2+ channels are open, producing the
plateau by slowing further repolarization.
3 Repolarization phase
• Ca2+ channels close.
• Many K+ channels open.
500
Fig. 12.9
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Cardiac skeleton
Pulmonary semilunar valve
Aortic
semilunar valve
Bicuspid
valve
Tricuspid
valve
Cardiac muscle
of the right
ventricle
Cardiac muscle
of the left ventricle
Posterior view
Fig. 12.15
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1
Action potentials originate in the sinoatrial (SA) node
and travel across the wall of the atrium (arrows) from
the SA node to the atrioventricular (AV) node.
Sinoatrial
(SA) node
Left atrium
1
Atrioventricular
(AV) node
2
Action potentials pass through the AV node and
along the atrioventricular (AV) bundle, which extends
from the AV node, through the fibrous skeleton, into
the interventricular septum.
2
3
The AV bundle divides into right and left bundle branches,
and action potentials descend to the apex of each ventricle
along the bundle branches.
Left ventricle
3
Atrioventricular
(AV) bundle
4
Action potentials are carried by the Purkinje fibers
from the bundle branches to the ventricular walls.
Right and left
bundle branches
Purkinje
fibers
4
Apex
Fig. 12.16
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QRS complex
(mV)
R
T
P
Q
S
PQ interval
QT interval
Time (seconds)
Fig. 12.6
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Aortic arch
Superior vena cava
Left pulmonary artery
Pulmonary trunk
Branches of right
pulmonary artery
Right pulmonary veins
Aortic semilunar valve
Left pulmonary veins
Pulmonary
semilunar valve
Left atrium
Right pulmonary veins
Bicuspid (mitral) valve
Right atrium
Left ventricle
Coronary sinus
Chordae tendineae
Tricuspid valve
Papillary muscles
Papillary muscles
Interventricular septum
Right ventricle
Inferior vena cava
Anterior view
Fig. 12.8
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary veins
Pulmonary veins
Left atrium
Aorta
Aorta
Left atrium
Bicuspid valve
(closed)
Bicuspid valve
(open)
Aortic semilunar
valve (closed)
Chordae tendineae
(tension low)
Aortic semilunar
valve (open)
Chordae tendineae
(tension high)
Papillary muscle
(relaxed)
Papillary muscle
(contracted)
Cardiac muscle
(relaxed)
Cardiac muscle
(contracted)
Left ventricle
(relaxed)
(a)
Anterior view
Left ventricle
(contracted)
(b)
Anterior view
Fig. 12.17
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Semilunar
valves opened
Semilunar
valves closed
AV valves
closed
AV valves
closed
1 Contraction of the ventricles causes
pressure in the ventricles to increase.
Almost immediately, the AV valves
close (the first heart sound). The
pressure in the ventricles continues
to increase.
2
Continued ventricular contraction
causes the pressure in the ventricles
to exceed the pressure in the pulmonary
trunk and aorta. As a result, the
semilunar valves are forced open,
and blood is ejected into the
pulmonary trunk and aorta.
Semilunar
valves closed
Semilunar
valves closed
AV valves
closed
AV valves
opened
5 The atria contract and complete
ventricular filling.
3 At the beginning of ventricular
diastole, the ventricles relax, and the
semilunar valves close (the second
heart sound).
Semilunar
valves closed
AV valves
opened
4 The AV valves open, and blood flows into
the ventricles. The ventricles fill
to approximately 70% of their
volume.
Fig. 12.19
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary
semilunar valve
Aortic
semilunar valve
Bicuspid
valve
Tricuspid
valve
Outline of
heart
© Terry Cockerham/Cynthia Alexander/ Synapse Media Productions
Fig. 12.22
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1 Sensory neurons (green) carry
action potentials from baroreceptors
to the cardioregulatory center.
Chemoreceptors in the medulla
oblongata influence the
cardioregulatory center.
Cardioregulatory center and
chemoreceptors in medulla oblongata
Sensory nerve
fibers
2 The cardioregulatory center controls
the frequency of action potentials in
the parasympathetic neurons (red )
extending to the heart. The
parasympathetic neurons decrease
the heart rate.
1
Carotid body
chemoreceptors
Sensory
nerve
fibers
3 The cardioregulatory center controls
the frequency of action potentials in
the sympathetic neurons (blue)
extending to the heart. The
sympathetic neurons increase the
heart rate and the stroke volume.
4 The cardioregulatory center
influences the frequency of action
potentials in the sympathetic
neurons (blue) extending to the
adrenal medulla. The sympathetic
neurons increase the secretion of
epinephrine and some
norepinephrine into the general
circulation. Epinephrine and
norepinephrine increase the heart
rate and stroke volume.
Baroreceptors
in wall of internal
carotid artery
Baroreceptors
in aorta
2
SA node
3
Heart
Sympathetic
nerve fibers to
adrenal gland
4
Circulation
Adrenal medulla
Epinephrine and norepinephrine
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Fig. 12.20
3
Baroreceptors in the carotid arteries and
aorta detect an increase in blood pressure.
The cardioregulatory center in the brain
decreases sympathetic stimulation of the
heart and adrenal medulla and increases
parasympathetic stimulation of the heart.
5
Blood pressure increases:
Homeostasis Disturbed
1
Blood pressure
(normal range)
The SA node and cardiac muscle (the
effectors) decrease activity and heart
rate and stroke volume decrease.
Blood pressure decreases:
Homeostasis Restored
6
Start here
Blood pressure decreases:
Homeostasis Disturbed
Baroreceptors in the carotid arteries and
aorta detect a decrease in blood pressure.
The cardioregulatory center in the brain
increases sympathetic stimulation of the
heart and adrenal medulla and decreases
parasympathetic stimulation of the heart.
Blood pressure
(normal range)
2
4
Blood pressure increases:
Homeostasis Restored
The SA node and cardiac muscle (the
effectors) increase activity and heart
rate and stroke volume increase.
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Fig. 12.21
3
4
Chemoreceptors in the medulla oblongata detect an
increase in blood pH (often caused by a decrease
in blood CO2). Control centers in the brain decrease
stimulation of the heart and adrenal medulla.
2
The SA node and cardiac muscle
(the effectors) decrease activity
and heart rate and stroke volume
decrease, reducing blood flow to
the lungs
5
Blood pH increases:
Homeostasis Disturbed
6
Start here
Blood pH decreases:
Homeostasis Disturbed
Chemoreceptors in the medulla oblongata detect a
decrease in blood pH (often caused by an increase
in blood CO2). Control centers in the brain increase
stimulation of the heart and adrenal medulla.
Blood pH
(normal range)
Blood pH
(normal range)
1
Blood pH decreases:
Homeostasis Restored
Blood pH increases:
Homeostasis Restored
The SA node and cardiac
muscle (the effectors) increase
activity and heart rate and stroke
volume increase, increasing
blood flow to the lungs.