heart physiology & conduction system ana ribić mentor: a. Žmegač horvat
TRANSCRIPT
HEART PHYSIOLOGY & CONDUCTION SYSTEM
Ana RibićMentor: A. Žmegač Horvat
PHYSIOLOGY
phase 1 - A-V Valves Open, Semilunar Valves Closed
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
QRS complex → ventricular depolarization
first heart sound (S1) ventricular pressure
rises - "isovolumetric" contraction
phase 3 - Aortic and Pulmonic Valves Open; AV Valves Remain Closed 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
after the QRS ventricular
repolarization T-wave ventricular pressure
falls slightly left atrial and right
atrial pressures gradually rise
phase 5 - All Valves Closed
aortic and pulmonic valves abruptly close
second heart sound (S2)
isovolumetric relaxation
dicrotic wave end-systolic volume LAP continues to rise
http://www.google.hr/imgres?imgurl=http://www.stethographics.com/heart/images/s123.jpg&imgrefurl=http://www.stethographics.com/main/physiology_hs_introduction.html&h=312&w=545&sz=55&tbnid=_Rg21HUd1Y5qXM:&tbnh=76&tbnw=133&prev=/images%3Fq%3Dheart%2Bsound&hl=hr&usg=__K4rsx1G_XCRY8TFdItVW4Fi9rBw=&ei=dYSeS8m_A4ee_gb0_qn7CQ&sa=X&oi=image_result&resnum=5&ct=image&ved=0CBkQ9QEwBA
phase 6 - A-V Valves Open
intraventricular pressures fall below their respective atrial pressures
ventricular filling third heart sound
(S3)
phase 7 - A-V Valves Open
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 bundle4. Right & left bundle branches -
nerve fibers that send impulses that cause the cardiac muscle tissue to contract
ELECTROCARDIOGRAM
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
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
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
This test is used to detect and evaluate many heart problems, such as heart attack, arrhythmia and heart failure
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