文档介绍：Zheng Yu ((郑郑煜煜) )
Department of Physiology
West China School of Preclinical
and Forensic Medicine
Sichuan University
Tel: 1360 800 2815
E-mail: ******@wcums.
QQ: 341152734
ChapterChapter 44 BloodBlood CirculationCirculation
Bioelectrical Activity and Physiological
Properties of Cardiac Muscle
Heart as a Pump
Functions of Blood Vessels
Regulation of Cardiovascular Activity
Coronary Circulation
Part One Bioelectrical Activity
and Physiological
Properties
of Cardiac Myocyte
I. Bioelectrical
Activity
1 1
2 2
0 3
0 3 0 3 0 3
4 4
-70 4 4
-90
Skeletal . Atrial M. Purkinje C. Sinus Node Node Region
Neuron Ventricular M. A-V Node
(not Node
Region)
Autorhythmic Nonautorhythmic
Fast Response C. Purkinje Atrial Muscle
Ventricular M.
Slow Response C. Sinus N. Node Region
A-V N.
(not Node
Region)
1. Transmembrane Potential
of Ventricular Cell
1) Resting Potential -90 mV
+ +
[K ]i>>>[K ]o
+
K flow out E K+
Higher P K+ (I K1 )
Na + inward background current
pump current (electronic Na +--K+ pump)
1 2
0mV
3
0
4
2) Action Potential
spike
1
0mV 2
3
0
4
Phase 0:
rapid depolarization
-90 -- +30 mV
1-- 2 ms Phase 0
200 —300 V/s
(fast response
potential)
Na + channels open
→ Na + flow in
→ ENa+
blocked by TTX
Phase 1:
initial rapid
repolarization Phase 1
+30 – 0 mV
10 ms
Na + channels inactivation
K+ flow outward
trantient outward
current (I to )
activated at –20 mV
blocked by
4-aminopyridine