Download HERAT PHYSIOLOGY & CONDUTION SYSTEM

HEART PHYSIOLOGY &
CONDUCTION SYSTEM
Ana Ribić
Mentor: A. Žmegač Horvat
PHYSIOLOGY
phase 1 - A-V Valves Open, Semilunar
Valves Closed
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p wave of ECG
atrial depolarization → atrial
contraction → pressure increases
→ pressure gradient across the
AV valves
blood flow across the open
atrioventricular (AV) valves
"a-wave"
ventricular end-diastolic volume
(EDV)
ventricular preload
phase 2 - All Valves Closed
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QRS complex → ventricular
depolarization
first heart sound (S1)
ventricular pressure rises "isovolumetric" contraction
phase 3 - Aortic and Pulmonic Valves
Open; AV Valves Remain Closed
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initial and rapid ejection of
blood into the aorta and
pulmonary arteries from the
left and right ventricles
total energy of blood
ventricular maximal outflow
pressure
blood continues to flow into
atria
phase 4 - Aortic and Pulmonic Valves
Open; AV Valves Remain Closed
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after the QRS
ventricular repolarization
T-wave
ventricular pressure falls
slightly
left atrial and right atrial
pressures gradually rise
phase 5 - All Valves Closed
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aortic and pulmonic valves
abruptly close
second heart sound (S2)
isovolumetric relaxation
dicrotic wave
end-systolic volume
LAP continues to rise
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phase 6 - A-V Valves Open
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intraventricular
pressures fall below
their respective atrial
pressures
ventricular filling
third heart sound (S3)
phase 7 - A-V Valves Open
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ventricles continue to
fill with blood and
expand →
intraventricular
pressures rise
aortic pressure and
pulmonary arterial
pressures continue to
fall
CONDUCTION SYSTEM
1. Sinoatrial node (SA node) -sends
the electrical impulse that triggers
each heartbeat
- upper area of the right atrium
2. Atrioventricular node (AV node) sends an impulse through the nerve
network to the ventricles
3. Common AV bundle
4. Right & left bundle branches nerve fibers that send impulses that
cause the cardiac muscle tissue to
contract
ELECTROCARDIOGRAM
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e-lek-tro-KAR-de-o-gram - EKG/ECG
painless test that records the heart's electrical
activity
signal causes the heart to contract and pump blood
and creates an electrical current that can be seen on
a graph called an electrocardiogram
signal causes the heartbeat
each heartbeat has two basic parts: diastole and
atrial and ventricular systole
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P wave - represents the
wave of depolarization
that spreads from the SA
node throughout the atria
P-R interval -represents
the time between the onset
of atrial depolarization
and the onset of
ventricular depolarization
QRS complex - ventricular
depolarization
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ST segment - time at
which the ventricle is
depolarized and
corresponds to the
plateau phase of the
ventricular action
potential
T wave - represents
ventricular repolarization
and is longer in duration
than depolarization
Q-T interval - represents
the time of both
ventricular depolarization
and repolarization
An EKG shows:
 how fast your heart is
beating
 whether the rhythm of
your heartbeat is steady
or irregular
 the strength and timing
of electrical signals as
they pass through each
part of your heart
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This test is used to detect
and evaluate many
heart problems, such as
heart attack, arrhythmia
and heart failure
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http://www.cvphysiology.com
http://www.nhlbi.nih.gov
http://www.wisegeek.com
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