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The Cardiovascular System. Heart Actions. Heart sounds Cardiac Muscle Cardiac Conduction system ECG. Normal for humans 60-100 bpm. Heartbeat. Systole = contraction Diastole = filling/relaxation b rady cardia vs. tachy cardia. Atrial S ystole /ventricular Diastole
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The Cardiovascular System Heart Actions • Heart sounds • Cardiac Muscle • Cardiac Conduction system • ECG
Heartbeat Systole = contraction Diastole = filling/relaxation bradycardia vs. tachycardia Atrial Systole/ventricular Diastole Atrial Diastole/Ventricular Systole
Dub Lub If you listen to your heartbeat, it makes a lub dub sound. The lub is when blood is pushed out of the heart into the body and the dub is the reloading of the heart with more blood ready to push it out to the body
Heart Sounds • Lub = • S1 • Ventricular systole • AV valves closing Latin for “to listen” – listen to internal body sounds. • Dub = • S2 • Ventricular diastole • Semilunar valves closing Hear all sorts of different heart sounds: http://www.wilkes.med.ucla.edu/inex.htm • Heart Murmur = • Sound of flow • “Grades” 1-6, 1-3 are soft sounds, 4,5,6 are very loud • “Innocent” or “normal” – sounds louder with fever • Easier to hear in children (less fat and muscle) • Could mean a valve problem or hole in heart
Cardiac Muscle – functional synctium Intercellular junctions – allow diffusion of ions and make impulse travel rapidly between cells Only 1 per cell (skeletal muscle is multinucleated)
Skeletal Muscle Smooth Muscle Cardiac Muscle
SA (sinoatrial) Node • SA (sinoatrial) node: • Pacemaker of the heart • Uses Ca,/Na ions to conduct impulse • Sets rate at 70-80 bpm • AV (atrioventricular) node: • Keeps synctium
ECG Body fluids conduct electric currents
Polarization – separated ions, at restDepolarized = cations flood cell, causes nerve impulse
Arrhythmias • Ventricular fibrillation – chaotic contraction, no blood pumped – BAD • Cause: obstructed coronary artery, drugs, electric shock, traumatic injury • Treat: “defibrilate” (AEDs)
100-200 bpm Normal – 75 bpm Bradycardia - <60bpm
Learn more about interpreting ECGs – try the self tests, learn how to measure, etc. http://courses.kcumb.edu/physio/ecg%20primer/normpractice1.htm