cardiac muscles and conductive system · cardiac muscles and conductive system 1.atrial muscle...
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CARDIAC MUSCLES
AND CONDUCTIVE SYSTEM
1.ATRIAL MUSCLE
2.VENTRICULAR MUSCL
3.CONDUCTIVE FIBERS
A.SA NODE
B.AV NODE
C.INTERNODAL FIBERS
D.AV FIBERS (BUNDLE OF HIS)
E.LEFT AND RIGHT BUNDLE BRANCH
F.PURKIINJE FIBERS
Fig. 9-7, p. 247
Sinoatrial
(SA) node
Right
atrium
Internodal
pathway
Right
branch
of bundle
of His Right
ventricle Purkinje
fibers
Left
ventricle
Left
branch
of bundle
of His
Left
atrium
Atrioventricular
(AV) node
Interatrial
pathway
Histology of cardiac muscle
Pacemaker activity of cardiac
autorhythmic cells
Direction of ventricular
excitation
ACTION POTENTIAL OF DIFFERENT PARTS OF THE
HEART
•1.PACE MAKER OF THE HEART SANODE
•2.ATRIAL ACTION POTENTIAL
•3.ACTION POTENTIAL OF THE VENTRICLES
•4.DELAY IN THE AV NODE
•5.HIGH VELOCITY IN THE PURKINJE FIBERS
•6.REFRACTORY PERIOD
•A.ABSOLUTE
•B.RELATIVE
-90
0
0
1 2
3
4
TIME
PHASE 0 = Rapid Depolarization
(inward Na+ current)
1 = Overshoot
2 = Plateau
(inward Ca++ current)
3 = Repolarization (outward K+ current)
4 = Resting Potential
Mechanical Response
ME
MB
RA
NE
P
OT
EN
TIA
L (
mV
)
0 0
-50 -50
-100 -100
SAN VENTRICULULAR CELL
ACTION POTENTIALS
0
1 2
3
4
4
0 3
CONTROL OF EXITATION AND
CONDUCTION
1-SYMPATHETIC
2-PARASYMPATHETIC
3-IONS