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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 •
Interatrial
pathway
Atrioventricular
(AV) node
Sinoatrial
(SA) node
Right
atrium
Left
atrium
Internodal
pathway
Right
branch
of bundle
of His
Left
branch
of bundle
of His
Left
ventricle
Right
ventricle
Purkinje
fibers
Fig. 9-7, p. 247
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 •
0
PHASE
0 = Rapid Depolarization
Mechanical Response
(inward Na+ current)
1
1 = Overshoot
2
2 = Plateau
(inward Ca++ current)
3 = Repolarization
+ current)
(outward
K
0
4 = Resting Potential
3
4
-90
TIME
MEMBRANE POTENTIAL (mV)
ACTION POTENTIALS
0
VENTRICULULAR
CELL
1
2
SAN
0
0
-50
0
3
-50
4
-100
-100
4
3
CONTROL OF EXITATION AND
CONDUCTION
1-SYMPATHETIC •
2-PARASYMPATHETIC •
3-IONS •