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2/3 of the mass lies to the left of the body’s
midline
The apex lies on the diaphragm
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Pericardium: 2 layered sac surrounding the heart
Myocardium: muscle tissue making up the walls
of the chambers
Endocardium: smooth lining of heart chambers
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Atria: receiving chambers
◦ Thin walled do to minimal work load
◦ Most work is done by gravity
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Ventricles: discharging chambers
◦ More muscular
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The Tricuspid Valve
◦ Right Heart
◦ 3 flaps
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The Mitral or Bicuspid Valve
◦ Left heart
◦ 2 flaps
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Pulmonary Semilunar Valve: at the beginning
of the pulmonary artery
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Aortic Semilunar Valve: at the beginning of
the aorta
Systole: Contracion
Diastole: Relaxation
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Body
Vena Cava
Right Atrium
Tricuspid Valve
Right Ventricle
Pulmonary Semilunar Valve
Pulmonary Artery
Lungs
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Lungs
Pulmonary Vein
Left Atrium
Mitral Valve
Left Ventricle
Aortic Semilunar Valve
Aorta
Body
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Blood which supplies oxygen and nutrients to
the myocardium of the hear, flows through
the right and left coronary arteries.
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SA (sinoatrial) Node: the pacemaker
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Generator of heart rhythm
Found in the right atrium
Initiates the electrical sequence
Starts contraction of the atria
AV (atrioventricular) Node:
 triggers contraction of the ventricles via perjunkie fibers and bundle
of His
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Ventricles contract from the bottom upwards.
 This makes sense because the outlets for the blood flow are at
the top.
http://www.youtube.com/watch?v=v3b-YhZmQu8
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An electrocardiogram (ECG or EKG) is a
graphical recording of the electrical events
occurring within the heart.
A normal ECG has 3 deflections:
 P Wave: Atrial Systole (initiated by SA Node)
 QRS Complex: Ventricular Systole
 T Wave: Ventricular Diastole
 Note: Atrial Diastole is masked by ventricular systole
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A long interval reveals that an impulse has been slowed or has
taken a longer route.
A short interval reflects an impulse which followed a shorter
route.
If a complex is absent, the electrical Impulse did not rise
normally, or was blocked at that part of the heart.
Lack of normal depolarization of the atria leads to an absent P
wave.
An absent QRS complex after a normal P wave indicates the
electrical impulse was blocked before it reached the ventricles.
Abnormally shaped complexes result from abnormal spread of
the impulse through the muscle tissue, such as in myocardial
infarction where the impulse cannot follow its normal pathway
because of tissue death or injury.
Note: Electrical patterns may also be changed by metabolic
abnormalities and by various medicines.