Cardiovascular System- The Heart PPT
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Give a detailed description of the superficial and internal anatomy of the heart, including the pericardium, the myocardium, and the cardiac muscle.
Explain the functioning of the valves of the heart and how they relate to the heart sounds.
Discuss the conductive pathway of the heart, and relate that to clinical uses of the ECG.
Pulmonary & Systemic Circuits
Location of Heart within Thoracic Cavity
1. Fibrous pericardium – tough, collagenous
3. Pericardial space with 10-20 ml of pericardial fluid
4. Serous visceral pericardium adheres to the heart surface (also known as epicardium)
Structure of Heart Wall
Endocardium: simple squamous epithelium continuous
Encircles bases of great vessels
Encircles bases of valves
Isolate atria from ventricles elctrically
Reinforce myocardium itself
Surface Anatomy of Heart
Left: high pressure pump – Right: low pressure pump Þ right chamber is thinner walled than left
Ventricles separated by interventricular septum
Structure and Function of Valves
4 sets of valves
Prevent backflow of blood
Close passively under blood pressure
Heart sounds produced by valve closure
Support for AV valves:
valves are restrained by chordae tendinae which are in turn attached to papillary muscles (prevention of backflow!)
Mitral Valve Prolapse
Not life threatening; may be lifestyle threatening
How can you diagnose?
Blood flow pattern through the heart
Actual physical contraction pattern of the myocardium as determined by the conduction.
The two atria are in systole and diastole together as are the two ventricles.
Auscultation of Heart Sounds:
1st HS: at beginning of ventricular contraction, due to?
2nd HS: at beginning of ventricular diastole, due to?
Coronary arteries: first branches off the ascending aorta.
Myocardial Infarction (MI)
Specialized muscle cells (autorhythmic cells) conduct APs to time and synchronize the action of the chambers
SA node -pacemaker, spontaneously depolarizes most rapidly and initiate heart beat, positioned on back wall of right atrium , transmits action potential to
AV node – (where the four chambers meet).
AV bundle (bundle of His) transmits down top of interventricular septum where it divides into two
Bundle branches, one of which supplies each ventricle where they branch into
Purkinje fibers reflect up external walls of ventricles and stimulate contraction of cardiac muscle cells as a unit.
Purkinje fibers extend into papillary muscles as well