Download Electrical Conduction PPT

Electrical Conduction
pathway of the heart:
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heart beat is regulated by electrical
impulses
SA node
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impulse begins in SA
(sinoatrial node; normal
rate 60 – 100 BPM)
group of nerve cells
located in right atrium
“pacemaker” of the heart
sends out electrical
impulses that spread out
over muscles in the atria
electrical impulse causes
atria to contract and
push blood into ventricles
electrical impulse then
travels to AV
(atrioventricular) node
AV node
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group of cells located
between atria and
ventricles (normal
rate 40 – 60 BPM)
AV node sends
electrical impulse
through nerve fibers
in the septum called
the Bundle of His
Bundle of His
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nerve fibers in the
septum
divides into right
and left bundle
branches
Right and left bundle
branches
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pathways that
carry the electrical
impulse down
through the
ventricles
bundles continue
to subdivide into
network of nerve
fibers throughout
ventricles called
Perkinje fibers
Perkinje fibers
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final fibers on electrical
conduction pathway
(normal rate 20 – 40
BPM)
spread electrical impulses
to all of the muscle tissue
in the ventricles
ventricles then contract
http://www.nhlbi.nih.gov
/health/healthtopics/topics/hhw/electric
al.html
EKG or ECG
(electrocardiogram)
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electrical conduction pattern occurs
about every 0.8 seconds
EKG or ECG (electrocardiogram):
machine that monitors and records
electrical impulses in the heart; used
to detect abnormal heart activity or
disease
EKG
p, qrs, t waves
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p wave: Atrial
depolarization or
contraction
qrs complex:
ventricular
depolarization or
contraction
t wave: ventricular
relaxation
Cardiac cycle
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Conists of mechanical and electrical
conduction
Both must function properly for normal
cardiac output