fig. 12.2 copyright © the mcgraw-hill companies, inc. permission required for reproduction or...
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Fig. 12.2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
O2
Systemiccirculation(to body)
Circulation totissues of head
Tissuecapillaries
Pulmonarycirculation(to lungs)
Lung
Lungcapillaries
Right side of heart
Tissuecapillaries
O2CO2
Circulation totissues oflower body
CO2
O2
Left sideof heart
CO2
Fig. 12.10-1
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Aortic arch
Left pulmonary artery
Branches of leftpulmonary arteries
Pulmonary trunk
Pulmonary veins
Left atrium
Bicuspid valve
Left ventricle
Interventricular septum
Superiorvena cava
Branches ofright pulmonaryarteries
Aortic semilunarvalvePulmonaryveins
Right atrium
Tricuspid valve
Papillary muscles
Right ventricle
(a)Inferiorvena cava
Pulmonary semilunarvalve
Fig. 12.5-1
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Superior vena cava
Branches of rightpulmonary artery
Right pulmonary veins
Right atrium
Coronary sulcus
Right coronary artery
Right ventricle
Inferior vena cava
(a) Anterior view
Aortic arch
Left pulmonary artery
Branches of leftpulmonary artery
Pulmonary trunk
Left pulmonary veins
Left atrium
Great cardiac vein(in anterior interventricular sulcus)
Anterior interventricular artery(in anterior interventricular sulcus)
Left ventricle
Fig. 12.13
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Branchingmuscle fibers
Intercalated disks
Nucleus of cardiacmuscle cell
LM 400x
Mitochondrion
Striations
Sarcolemma (cell membrane)
Connective tissue
(b)(a)
Myofibrils
Sarcomere
Sarcoplasmicreticulum
T tubule
b: © Ed Reschke
Fig. 12.11
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Aortic arch
Pulmonarytrunk
Left atrium
Posterior veinof left ventricle
Coronarysinus
Greatcardiacvein
Leftventricle
Anterior view(b)
Right ventricle
Smallcardiacvein
Middlecardiac vein
Superiorvena cava
Rightatrium Into
rightatrium
Aortic arch
Pulmonarytrunk
Left coronaryartery
Left atrium
Circumflexartery
Left marginalartery
Anteriorinterventricularartery
Left ventricle
Anterior view(a)
Right ventricle
Rightmarginalartery
Posteriorinterventricularartery
Rightcoronaryartery
Rightatrium
Superiorvena cava
Aorticsemilunarvalve
Fig. 12.14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
–85
1 2
0
(mV
)
1 2
0
Depolarization phase• Na+ channels open.• K+ channels begin to open.
Repolarization phase• Na+ channels close.• K+ channels continue to open, causing
repolarization.• K+ channels close at the end of
repolarization and return the membranepotential to its resting value.
Depolarization phase• Na+ channels open.• Ca2+ channels open.
Plateau phase• Na+ channels close.• Some K+ channels open, causing
repolarization.• Ca2+ channels are open, producing the
plateau by slowing further repolarization.
Repolarization phase• Ca2+ channels close.• Many K+ channels open.
1
2
1
2
3
1
2 1
2
3
Skeletal Muscle Cardiac Muscle
Plateauphase
Repolarizationphase
RepolarizationphaseDepolarization
phase
–85
(mV
)
500
Time (ms)Time (ms)
Depolarizationphase
(a) (b)
Fig. 12.9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary semilunar valve
Aorticsemilunar valve
Tricuspidvalve
Cardiac muscleof the rightventricle
Cardiac muscleof the left ventricle
Posterior view
Bicuspidvalve
Cardiac skeleton
Fig. 12.15
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4
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2
4
Action potentials originate in the sinoatrial (SA) nodeand travel across the wall of the atrium (arrows) fromthe SA node to the atrioventricular (AV) node.
Action potentials pass through the AV node andalong the atrioventricular (AV) bundle, which extendsfrom the AV node, through the fibrous skeleton, intothe interventricular septum.
The AV bundle divides into right and left bundle branches,and action potentials descend to the apex of each ventriclealong the bundle branches.
Action potentials are carried by the Purkinje fibersfrom the bundle branches to the ventricular walls.
ApexPurkinjefibers
Right and leftbundle branches
Atrioventricular(AV) bundle
Sinoatrial(SA) node
Atrioventricular(AV) node
Left atrium
Left ventricle
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Fig. 12.16 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(mV
)
R
P
T
Q
S
QRS complex
Time (seconds)
QT intervalPQ interval
Fig. 12.6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Aortic arch
Left pulmonary artery
Pulmonary trunk
Right pulmonary veins
Left pulmonary veins
Left atrium
Bicuspid (mitral) valve
Left ventricle
Chordae tendineae
Papillary muscles
Interventricular septum
Anterior viewInferior vena cava
Right ventricle
Papillary muscles
Tricuspid valve
Coronary sinus
Right atrium
Right pulmonary veins
Pulmonarysemilunar valve
Aortic semilunar valve
Branches of rightpulmonary artery
Superior vena cava
Fig. 12.8
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonary veins
Aorta
Aortic semilunarvalve (closed)
(a) Anterior view
Left ventricle(relaxed)
Cardiac muscle(relaxed)
Papillary muscle(relaxed)
Left atrium
Bicuspid valve(open)
Aorta
Pulmonary veins
Left atrium
Bicuspid valve(closed)
Chordae tendineae(tension high)
Papillary muscle(contracted)
Cardiac muscle(contracted)
Left ventricle(contracted)
Aortic semilunarvalve (open)Chordae tendineae
(tension low)
(b) Anterior view
Fig. 12.17 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Contraction of the ventricles causespressure in the ventricles to increase.Almost immediately, the AV valvesclose (the first heart sound). Thepressure in the ventricles continuesto increase.
Continued ventricular contractioncauses the pressure in the ventriclesto exceed the pressure in the pulmonarytrunk and aorta. As a result, thesemilunar valves are forced open,and blood is ejected into thepulmonary trunk and aorta.
The atria contract and completeventricular filling.
The AV valves open, and blood flows intothe ventricles. The ventricles fillto approximately 70% of theirvolume.
At the beginning of ventriculardiastole, the ventricles relax, and thesemilunar valves close (the secondheart sound).
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3
4
5
1
Semilunarvalves closed
Semilunarvalves opened
AV valvesclosed
AV valvesclosed
Semilunarvalves closed
AV valvesopened
Semilunarvalves closed
AV valvesclosed
Semilunarvalves closed
AV valvesopened
Fig. 12.19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pulmonarysemilunar valve
Aorticsemilunar valve
Bicuspidvalve
Outline ofheart
Tricuspidvalve
© Terry Cockerham/Cynthia Alexander/ Synapse Media Productions
Fig. 12.22
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sensory neurons (green) carryaction potentials from baroreceptorsto the cardioregulatory center.Chemoreceptors in the medullaoblongata influence thecardioregulatory center.
The cardioregulatory center controlsthe frequency of action potentials inthe parasympathetic neurons (red )extending to the heart. Theparasympathetic neurons decreasethe heart rate.
The cardioregulatory center controlsthe frequency of action potentials inthe sympathetic neurons (blue)extending to the heart. Thesympathetic neurons increase theheart rate and the stroke volume.
The cardioregulatory centerinfluences the frequency of actionpotentials in the sympatheticneurons (blue) extending to theadrenal medulla. The sympatheticneurons increase the secretion ofepinephrine and somenorepinephrine into the generalcirculation. Epinephrine andnorepinephrine increase the heartrate and stroke volume.
Adrenal medullaEpinephrine and norepinephrine
Circulation
Heart
SA node
Baroreceptorsin aorta
Carotid bodychemoreceptors
Baroreceptorsin wall of internalcarotid artery
Cardioregulatory center andchemoreceptors in medulla oblongata
Sensory nervefibers
Sensorynervefibers
Sympatheticnerve fibers toadrenal gland
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4
Fig. 12.20Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Blo
od
pre
ssu
re(n
orm
al r
ang
e)
The SA node and cardiac muscle (theeffectors) increase activity and heartrate and stroke volume increase.
The SA node and cardiac muscle (theeffectors) decrease activity and heartrate and stroke volume decrease.
Baroreceptors in the carotid arteries andaorta detect a decrease in blood pressure.
The cardioregulatory center in the brainincreases sympathetic stimulation of theheart and adrenal medulla and decreasesparasympathetic stimulation of the heart.
Baroreceptors in the carotid arteries andaorta detect an increase in blood pressure.
The cardioregulatory center in the braindecreases sympathetic stimulation of theheart and adrenal medulla and increasesparasympathetic stimulation of the heart.
Blo
od
pre
ssu
re(n
orm
al r
ang
e)
Blood pressure increases:Homeostasis Disturbed
Blood pressure decreases:Homeostasis Disturbed
2
3
4
61
Start here
Blood pressure decreases:Homeostasis Restored
5
Blood pressure increases:Homeostasis Restored
Fig. 12.21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Blo
od
pH
(no
rmal
ran
ge)
The SA node and cardiacmuscle (the effectors) increaseactivity and heart rate and strokevolume increase, increasingblood flow to the lungs.
The SA node and cardiac muscle(the effectors) decrease activityand heart rate and stroke volumedecrease, reducing blood flow tothe lungs
Chemoreceptors in the medulla oblongata detect anincrease in blood pH (often caused by a decreasein blood CO2). Control centers in the brain decreasestimulation of the heart and adrenal medulla.
Chemoreceptors in the medulla oblongata detect adecrease in blood pH (often caused by an increasein blood CO2). Control centers in the brain increasestimulation of the heart and adrenal medulla.
Blood pH decreases:Homeostasis Disturbed
Blood pH increases:Homeostasis Restored
Blood pH decreases:Homeostasis Restored
2
3
4
5
1 6
Blo
od
pH
(no
rmal
ran
ge)
Start here
Blood pH increases:Homeostasis Disturbed