Download 14 - El Camino College

POWERPOINT® LECTURE SLIDE PRESENTATION
by LYNN CIALDELLA, MA, MBA, The University of Texas at Austin
Additional Text by J Padilla exclusively for Physiology 31 at ECC
UNIT 3
14
PART A
Cardiovascular
Physiology
HUMAN PHYSIOLOGY
AN INTEGRATED APPROACH
DEE UNGLAUB SILVERTHORN
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
FOURTH EDITION
Structure of the Heart
The heart valves ensure one-way flow
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Figure 14-7g
Heart Valves
PLAY Animation: Cardiovascular System: Anatomy Review: The Heart
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-9
Heart Valves
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Histology of Myocardium
 Involuntary muscle
 Striated, has sarcomeres
 Many mitochondria
 Uni- or binucleated
 Branched
 Intercalated Disc
 Rhythmic contractions
 Does not fatigue as
easily as skeletal
 Does not have individual
neuromuscular junctions
 Independent contractions
 Require
high
O2
Copyright © 2007
Pearson
Education, Inc., publishing as Benjamin Cummings
Cardiac Muscle versus Skeletal Muscle
 Smaller and have single nucleus per fiber
 Have intercalated disks
 Desmosomes allow force to be transferred
 Gap Junctions provide electrical connection
 T-tubules are larger and branch
 Sarcoplasmic reticulum is smaller
 Mitochondria occupy one-third of cell volume
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Excitation-contraction coupling and relaxation
in cardiac muscle
1 Action potential enters
from adjacent cell.
Ca2+
ECF
1
2 Voltage-gated Ca2+
channels open. Ca2+
enters cell.
ICF
Ryanodine
receptor-channel
3 Ca2+ induces Ca2+ release
through ryanodine
receptor-channels (RyR).
2
3
SR
Sarcoplasmic
reticulum
(SR)
Ca2+
T-tubule
4
Ca2+
spark
5
4 Local release causes
Ca2+ spark.
2+
5 Summed Ca Sparks
2+
create a Ca signal.
2+
6 Ca ions bind to troponin
to initiate contraction.
Ca2+ signal
6
Contraction
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-11, steps 1–6
Excitation-contraction coupling and relaxation
in cardiac muscle
1 Action potential enters
from adjacent cell.
Ca2+
ECF
1
2 Voltage-gated Ca2+
channels open. Ca2+
enters cell.
ICF
Ryanodine
receptor-channel
3 Ca2+ induces Ca2+ release
through ryanodine
receptor-channels (RyR).
2
3
SR
Sarcoplasmic
reticulum
(SR)
Ca2+
T-tubule
Ca2+
stores
4 Local release causes
Ca2+ spark.
2+
5 Summed Ca Sparks
2+
create a Ca signal.
ATP
4
Ca2+
spark
8
Ca2+
2+
6 Ca ions bind to troponin
to initiate contraction.
5
7 Relaxation occurs when
Ca2+ unbinds from troponin.
Ca2+ signal
Ca2+
6
Contraction
7
Relaxation
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Actin
2+
8 Ca is pumped back
into the sarcoplasmic
reticulum for storage.
Myosin
Figure 14-11, steps 1–8
Excitation-contraction coupling and relaxation
in cardiac muscle
9
Ca2+
Ca2+
10
3
Na+
ECF
1
1 Action potential enters
from adjacent cell.
2 K+
ATP
ICF
Ryanodine
receptor-channel
2 Voltage-gated Ca2+
channels open. Ca2+
enters cell.
3 Na+
Ca2+
3 Ca2+ induces Ca2+ release
through ryanodine
receptor-channels (RyR).
2
3
SR
Sarcoplasmic
reticulum
(SR)
Ca2+
T-tubule
Ca2+
stores
4 Local release causes
Ca2+ spark.
2+
5 Summed Ca Sparks
2+
create a Ca signal.
ATP
4
Ca2+
spark
8
Ca2+
2+
6 Ca ions bind to troponin
to initiate contraction.
5
Ca2+
7 Relaxation occurs when
Ca2+ unbinds from troponin.
signal
Ca2+
6
7
Actin
2+
8 Ca is pumped back
into the sarcoplasmic
reticulum for storage.
9 Ca2+ is exchanged
with Na+.
Contraction
Relaxation
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Myosin
10 Na+ gradient is maintained
by the Na+-K+-ATPase.
Figure 14-11, steps 1–10
Myocardial Contractile Cells
Action potential of a cardiac contractile cell
+20
Na+ passes through
double gated voltage
channels
Plateau results from
decreased K+ and
increased Ca++
Plateau end when flux
is reversed
2
PK and PCa
0
Membrane potential (mV)
Resting membrane
potential is -90mv.
PX = Permeability to ion X
PNa
1
-20
-40
3
0
PNa
-60
-80
PK and PCa
4
4
-100
0
Phase
100
200
Time (msec)
300
Membrane channels
0
Na+ channels open
1
Na+ channels close
2
Ca2+ channels open; fast K+ channels close
3
Ca2+ channels close; slow K+ channels open
4
Resting potential
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Figure 14-13
Myocardial Contractile Cells
Refractory periods and summation in skeletal and
cardiac muscle- this prevents summation as it
happens in skeletal muscle
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Figure 14-14c
Modulation of Heart Rate
by the Nervous System
Sympathetic
stimulation
targets If
channels to
open rapidly.
Parasympathet
ic stimuation
targets K+ and
Ca++ channels,
it hyperpolarizes the
cell and slows
depolarization
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-16
Electrical Conduction in Myocardial Cells
1% of
myocardial cells
are designed to
spontaneously
generate an
action potential.
They can
contract without
outside signal=
autorhythmic.
Pacemaker cells
do not have
sarcomeres
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Figure 14-17
Electrical Conduction in Heart
1
1
SA node
AV node
2
THE CONDUCTING SYSTEM
OF THE HEART
1 SA node depolarizes.
SA node
3
Internodal
pathways
2 Electrical activity goes
rapidly to AV node via
internodal pathways.
3 Depolarization spreads
more slowly across
atria. Conduction slows
through AV node.
AV node
A-V bundle
Bundle branches
4
Purkinje
fibers
4 Depolarization moves
rapidly through ventricular
conducting system to the
apex of the heart.
5 Depolarization wave
spreads upward from
the apex.
5
Purple shading in steps 2–5 represents depolarization.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-18
Electrical Conduction & Einthoven’s Triangle
 AV node
 Direction of electrical
signals
 Delay the transmission of
action potentials
 SA node
 Set the pace of the
heartbeat at 70 bpm
 AV node (50 bpm) and
Purkinje fibers (25-40
bpm) can act as
pacemakers under some
conditions
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Electrical Activity
Comparison of an ECG and a myocardial action
potential
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Figure 14-22
The Electrocardiogram
ECG give info on heart rate, heart rhythm, conduction
velocity, and heart condition. Three major waves: P
wave, QRS complex, and T wave
Waves correspond to events of the cardiac cycle.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-20
Electrical Activity
Correlation between an ECG and electrical events in the
heart
P wave: atrial
depolarization
START
P
The end
R
PQ or PR segment:
conduction through
AV node and A-V
bundle
T
P
P
QS
Atria contract.
T wave:
ventricular
Repolarization
Repolarization
R
T
P
ELECTRICAL
EVENTS
OF THE
CARDIAC CYCLE
QS
P Q wave
Q
ST segment
R
R wave
R
P
QS
P
R
Ventricles contract.
Q
P
S wave
QS
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-21
Electrical Activity
The P wave
reflects the
activity of the
atria. The atria
contract from top
to bottom so the
P-wave ends
after full atrial
depolarization
P wave: atrial
depolarization
START
P
PQ or PR segment:
conduction through
AV node and A-V
bundle
P
Atria contract.
ELECTRICAL
EVENTS
OF THE
CARDIAC CYCLE
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Figure 14-21 (2 of 9)
Electrical Activity
The P-Q
segment reflects
the flow of
current along the
interventricular
septum via the
AV node and AV
bundle. This is
the time when
the ventricles
are relaxed and
filling with blood
P wave: atrial
depolarization
START
P
PQ or PR segment:
conduction through
AV node and A-V
bundle
P
Atria contract.
ELECTRICAL
EVENTS
OF THE
CARDIAC CYCLE
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P Q wave
Q
Figure 14-21 (3 of 9)
Electrical Activity
The QRS complex
occurs while the
ventricles contraction
(depolarize) from the
apex & upwards. At the
end of the contraction
all blood volume to be
expelled as been
pushed out.
S-T segment happens
during ventricular
repolarization (relax)
P wave: atrial
depolarization
START
P
PQ or PR segment:
conduction through
AV node and A-V
bundle
P
Atria contract.
ELECTRICAL
EVENTS
OF THE
CARDIAC CYCLE
P Q wave
Q
ST segment
R
R wave
R
P
QS
P
R
Ventricles contract.
Q
P
S wave
QS
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Figure 14-21 (6 of 9)
Electrical Activity
The T-wave
indicates
ventricular
repolarizationmeaning that
the muscle is
coming back to
a resting state.
At this point the
chambers are
ready to
receive blood
P wave: atrial
depolarization
START
P
The end
R
PQ or PR segment:
conduction through
AV node and A-V
bundle
T
P
P
QS
Atria contract.
T wave:
ventricular
Repolarization
Repolarization
R
T
P
ELECTRICAL
EVENTS
OF THE
CARDIAC CYCLE
QS
P Q wave
Q
ST segment
R
R wave
R
P
QS
P
R
Ventricles contract.
Q
P
S wave
QS
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-
Electrical Activity
Normal and abnormal electrocardiograms
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Figure 14-23
Mechanical Events
Mechanical events of the cardiac cycle
1
START
5
Late diastole: both sets of
chambers are relaxed and
ventricles fill passively.
Isovolumic ventricular
relaxation: as ventricles
relax, pressure in ventricles
falls, blood flows back into
cups of semilunar valves
and snaps them closed.
Ventricular ejection:
4 as ventricular pressure
rises and exceeds
pressure in the arteries,
the semilunar valves
open and blood is
ejected.
Atrial systole: atrial contraction
forces a small amount of
additional blood into ventricles.
2
3
Isovolumic ventricular
contraction: first phase of
ventricular contraction pushes
AV valves closed but does not
create enough pressure to open
semilunar valves.
PLAY Animation: Cardiovascular System: Cardiac Cycle
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-24
Mechanical Events
1
START
Late diastole: both sets of
chambers are relaxed and
ventricles fill passively.
2
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Atrial systole: atrial contraction
forces a small amount of
additional blood into ventricles.
Figure 14-24, steps 1–2
Mechanical Events
1
START
Late diastole: both sets of
chambers are relaxed and
ventricles fill passively.
Atrial systole: atrial contraction
forces a small amount of
additional blood into ventricles.
2
3
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Isovolumic ventricular
contraction: first phase of
ventricular contraction pushes
AV valves closed but does not
create enough pressure to open
semilunar valves.
Figure 14-24, steps 1–3
Mechanical Events
1
START
Late diastole: both sets of
chambers are relaxed and
ventricles fill passively.
Atrial systole: atrial contraction
forces a small amount of
additional blood into ventricles.
2
Ventricular ejection:
4 as ventricular pressure
rises and exceeds
pressure in the arteries,
the semilunar valves
open and blood is
ejected.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
3
Isovolumic ventricular
contraction: first phase of
ventricular contraction pushes
AV valves closed but does not
create enough pressure to open
semilunar valves.
Figure 14-24, steps 1–4
Mechanical Events
1
START
5
Late diastole: both sets of
chambers are relaxed and
ventricles fill passively.
Isovolumic ventricular
relaxation: as ventricles
relax, pressure in ventricles
falls, blood flows back into
cups of semilunar valves
and snaps them closed.
Ventricular ejection:
4 as ventricular pressure
rises and exceeds
pressure in the arteries,
the semilunar valves
open and blood is
ejected.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Atrial systole: atrial contraction
forces a small amount of
additional blood into ventricles.
2
3
Isovolumic ventricular
contraction: first phase of
ventricular contraction pushes
AV valves closed but does not
create enough pressure to open
semilunar valves.
Figure 14-24, steps 1–5
Cardiac Cycle
Left ventricular pressure-volume changes during one
cardiac cycle
KEY
EDV = End-diastolic volume
ESV = End-systolic volume
Stroke volume
Left ventricular pressure (mm Hg)
120
D
ESV
80
C
One
cardiac
cycle
40
EDV
B
A
0
65
100
Left ventricular volume (mL)
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135
Figure 14-25
Cardiac Cycle
At the beginning of the diastolic phase the
ventricles are relax and contain a very small
amount of blood
KEY
Left ventricular pressure (mm Hg)
EDV = End-diastolic volume
ESV = End-systolic volume
120
80
40
A
0
65
100
Left ventricular volume (mL)
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135
Figure 14-25 (1 of 4)
Cardiac Cycle
At then of the diastolic phase the volume as
increased because the ventricle has filled after
the ventricles contracted
KEY
Left ventricular pressure (mm Hg)
EDV = End-diastolic volume
ESV = End-systolic volume
120
80
40
EDV
B
A
0
65
100
Left ventricular volume (mL)
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135
Figure 14-25 (2 of 4)
Cardiac Cycle
At point C (systole phase) the pressure has
increased but the volume has not changed
KEY
EDV = End-diastolic volume
ESV = End-systolic volume
Left ventricular pressure (mm Hg)
120
80
C
40
EDV
B
A
0
65
100
Left ventricular volume (mL)
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135
Figure 14-25 (3 of 4)
Cardiac Cycle
At the end of systole the pressure is at is
highest and the volume has dropped.
Stroke volume= EDV - ESV
KEY
Left ventricular pressure (mm Hg)
EDV = End-diastolic volume
ESV = End-systolic volume
Stroke volume
120
D
ESV
80
C
One
cardiac
cycle
40
EDV
B
A
0
65
100
Left ventricular volume (mL)
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135
Figure 14-25 (4 of 4)
Wiggers Diagram
This diagram
shows the
relationship
between the
cardiac cycle,
the ECG, the
heart sounds,
and pressure
changes in the
left ventricle
and aorta
0
Time (msec)
200 300 400
100
QRS
complex
Electrocardiogram
(ECG)
P
500
600
700
800
QRS
complex
Cardiac cycle
T
P
120
90
Dicrotic
notch
Pressure
(mm Hg)
Left
ventricular
pressure
60
Left atrial
30 pressure
S1
Heart
sounds
S2
135
Left
ventricular
volume
(mL)
Atrial systole
65
Atrial Ventricular
systole
systole
Isovolumic
Ventricular
ventricular
systole
contraction
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Ventricular
diastole
Early
ventricular
diastole
Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
This shows the correlation between the
carciac cycle and the ECG. Notice between
the T wave of one and P wave of another
the ventricles are relaxed while the atria are
filling and beginning to empty prior to atrial
depolarization
0
Electrocardiogram
(ECG)
P
100
Time (msec)
200 300 400
QRS
complex
Isovolumic
ventricular
contraction
Ventricular
systole
600
700
800
QRS
complex
Cardiac cycle
T
P
Atrial Ventricular
systole
systole
Atrial systole
500
Ventricular
diastole
Early
ventricular
diastole
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Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
This phase shows the changes in
blood volume as the ventricle contracts
(depolarizes) or relaxes (repolarizes)
0
100
Time (msec)
200 300 400
500
600
700
800
135
Left
ventricular
volume
(mL)
Atrial systole
65
Isovolumic
ventricular
contraction
Atrial Ventricular
systole
systole
Ventricular
systole
Ventricular
diastole
Early
ventricular
diastole
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Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
You can see the relationship between pressure chages in teh
atrium and the cardiac cycle. Notice that the lowest atrial
pressure is during ventricular diastole.
0
100
Time (msec)
200 300 400
500
600
700
800
90
Pressure
(mm Hg)
60
30
Left atrial
pressure
Left
ventricular
volume
(mL)
135
65
Atrial Ventricular
systole
systole
Ventricular
diastole
Atrial systole
Isovolumic
Ventricular
Early
ventricular
systole Cummingsventricular
Copyright © 2007 Pearson Education,
Inc., publishing as Benjamin
contraction
diastole
Atrial
systole
Late
ventricular
diastole
Atrial
systoleFigure
14-26
Wiggers Diagram
This shows changes in ventricular pressure and
valve sounds as the AV valve (S1) and
semilunar valves (S2) close.
0
Time (msec)
200 300 400
100
500
600
700
800
120
90
Pressure
(mm Hg)
60
Left
ventricular
pressure
30
S1
Heart
sounds
135
Atrial systole
Isovolumic
ventricular
contraction
S2
Atrial Ventricular
systole
systole
Ventricular
systole
Ventricular
diastole
Early
ventricular
diastole
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Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
This shows changes in ventricular pressure
and ventricular blood volume.
0
100
Time (msec)
200 300 400
500
600
700
800
90
Pressure
(mm Hg)
60
30
Left
ventricular
volume
(mL)
135
Left
ventricular
pressure
S1
S2
65
Atrial Ventricular
systole
systole
Atrial systole
Isovolumic
ventricular
contraction
Ventricular
systole
Ventricular
diastole
Early
ventricular
diastole
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
The top line shows changes in pressure of the aorta as the left
ventricle contracts or relaxes. The dicrotic notch occurs as a
sharp drop in pressure results from a drop in blood flow once
the ventricle begins to relax
0
Time (msec)
200 300 400
100
500
600
700
800
120
90
Pressure
(mm Hg)
60
Dicrotic
notch
Left
ventricular
pressure
30
Heart
sounds
S1
S2
Atrial Ventricular
systole
systole
Atrial systole
Isovolumic
ventricular
contraction
Ventricular
systole
Ventricular
diastole
Early
ventricular
diastole
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Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
0
Time (msec)
200 300 400
100
500
600
700
800
120
90
Dicrotic
notch
Pressure
(mm Hg)
Left
ventricular
pressure
60
Left atrial
30 pressure
Heart
sounds
S1
S2
Atrial Ventricular
systole
systole
Atrial systole
Isovolumic
ventricular
contraction
Ventricular
systole
Ventricular
diastole
Early
ventricular
diastole
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Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26
Wiggers Diagram
0
QRS
complex
Electrocardiogram
(ECG)
This shows
all the events
that are
happening
during one
complete
ECG wave
Time (msec)
200 300
100
P
T
120
90
Pressure
(mm Hg)
Left
ventricular
pressure
60
Left atrial
30 pressure
S1
Heart
sounds
135
Left
ventricular
volume
(mL)
65
Atrial Ventricular
systole
systole
Ventricular
systole
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-26
Wiggers Diagram
0
This
shows all
the
changes
happening
during
ventricular
diastole
Time (msec)
200 300 400
100
QRS
complex
Electrocardiogram
(ECG)
P
500
600
700
800
Cardiac cycle
T
120
90
Dicrotic
notch
Pressure
(mm Hg)
Left
ventricular
pressure
60
Left atrial
30 pressure
S1
Heart
sounds
S2
135
Left
ventricular
volume
(mL)
65
Atrial Ventricular
systole
systole
Ventricular
diastole
Late
ventricular
diastole
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14-26
Wiggers Diagram
0
These
are all
the
events
during
one
complete
cardiac
cycle
Time (msec)
200 300 400
100
QRS
complex
Electrocardiogram
(ECG)
P
500
600
700
800
QRS
complex
Cardiac cycle
T
P
120
90
Dicrotic
notch
Pressure
(mm Hg)
Left
ventricular
pressure
60
Left atrial
30 pressure
S1
Heart
sounds
S2
135
Left
ventricular
volume
(mL)
Atrial systole
65
Atrial Ventricular
systole
systole
Isovolumic
ventricular
contraction
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Ventricular
systole
Ventricular
diastole
Early
ventricular
diastole
Atrial
systole
Late
ventricular
diastole
Atrial
systole
Figure 14-26