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The Heart. Location. 2/3 of the mass lies to the left of the body’s midline The apex lies on the diaphragm. Anatomy of the Heart. The Heart Tissues. Pericardium: 2 layered sac surrounding the heart Myocardium : muscle tissue making up the walls of the chambers
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Location • 2/3 of the mass lies to the left of the body’s midline • The apex lies on the diaphragm
The Heart Tissues • Pericardium: 2 layered sac surrounding the heart • Myocardium: muscle tissue making up the walls of the chambers • Endocardium: smooth lining of heart chambers
The Heart Chambers • Atria: receiving chambers • Thin walled do to minimal work load • Most work is done by gravity • Ventricles: discharging chambers • More muscular
The AV Valves • The Tricuspid Valve • Right Heart • 3 flaps • The Mitral or Bicuspid Valve • Left heart • 2 flaps
The Semilunar Valves • Pulmonary Semilunar Valve: at the beginning of the pulmonary artery • Aortic Semilunar Valve: at the beginning of the aorta
Heart Action Systole: Contraction Diastole: Relaxation
The Action of the Right Heart • Body • Vena Cava • Right Atrium • Tricuspid Valve • Right Ventricle • Pulmonary Semilunar Valve • Pulmonary Artery • Lungs
The Action of the Left Heart • Lungs • Pulmonary Vein • Left Atrium • Mitral Valve • Left Ventricle • Aortic Semilunar Valve • Aorta • Body
Coronary Circulation • Blood which supplies oxygen and nutrients to the myocardium of the hear, flows through the right and left coronary arteries.
Conduction System • SA (sinoatrial) Node: the pacemaker • 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 perkunjiefibers and bundle of His • 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
Electrocardiogram (ECG) • 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
Things to look for in an ECG: • 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.