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The heart
| Term | Definition |
|---|---|
| Pericardium | double- walled sac around the heart Purpose: protect and anchor; prevents overfilling; allows it to work in friction-free environment |
| Three layers of heart wall? | Epicardium, Myocardium, Endocardium |
| Vessels that return blood to the heart? | Superior vena cava, Inferior vena cava, Right pulmonary vein, Left pulmonary vein |
| Vessels away from the heart? | Pulmonary trunk>>>branches into R & L pulmonary arteries Ascending Aorta>>> branches into 3 Brachial Left common artery Subclavian artery |
| Arteries | Carry blood away from heart; Oxygenated blood |
| Veins | Carry blood to the heart; Deoxygenated blood |
| Atria | Receiving chambers of the heart; Blood enters the right atria from superior vena cava & inferior vena cava left atria to pulmonary veins |
| Ventricles | Decharging chambers; Right ventricle pumps blood into pulmonary trunk Left ventricle pumps into aorta |
| Blood Flow | 1. R atrium to tricuspid valve to R ventricle to Pulmonary Valve;Then to Pulmonary arteries straight to the lungs; When comes back from lungs goes to Pulmonary veins; L Atrium to Bicuspid valve; L ventricle to aortic; Aorta to the rest of the body |
| Heart valves( AV Valves) | Lie between atrium and ventricles; Prevents backflow into the atria when ventricles contract; Unidirectional(moving one way) Ex: Tricuspid & Bicuspid valve |
| Heart Valves( Semilunar Valves) | Prevent backflow into the associated ventricles Ex: Aortic & Pulmonary |
| ECG | Required electrical activity |
| P wave | 1st; refers to depolarization of SA node |
| SA Node | The heart's pacemaker |
| QRS | Vertical depolarization |
| T-wave | Vertical Repolarization |
| Articular repolarization | This is masked by QRS |
| Heart sounds | Lub-dup |
| Lub | AV valves closed; signifies the beginning of systole |
| Dup | occurs when SL valves closed; results in diastole |
| Systole | muscle contraction |
| Dyastole | muscle relaxed |