Lecture7 - Lecture#7 EKG=(ECG elecrocardiogram(figure 1 p...

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Lecture #7 09/07/2008 15:54:00 EKG= (ECG) elecrocardiogram (figure 1) p wave- activate depolarization and contraction QRS complex- ventricular depolarization and contraction T wave- repolarization of the ventricules IV. Blood pressure/ hemodynamics A. Blood pressure Systole= period where ventricles are contracting (heartbeat marks beginning and end) Diastole= ventricles are relaxed Blood pressure= systemic arterial pressure o Systolic/diastolic= blood pressure ~120/80 Mean arterial pressure: o Map= CO  ×  TPR B. Cardiac output (CO) α  MAP cardiac output= stroke volume  ×  heart rate CO= SV  ×  HR Volume pumped/min= vol. pumped/beat  ×  beat/min 1. stroke volume:  a. sympathetic stimulation of the heart (heart rate goes up)
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Increases Ca 2+ influx into cardiac muscle fibers  increase tension of muscle, increase stroke volume; push out more blood in single beat b. Frank-Starling Mechanism:  Stretch heart muscle   more forceful contraction Increase venous return  increase atrial stretch   increase atrial contraction  increase ventricular stretch  increase ventricular contraction  increase stroke volume (amount of blood pumped out) “ more blood in, more blood out” how to change stroke volume change blood volume (H2O, salt, diuretic, hemorrhage) exercise 2. Heart Rate: a. parasympathetic NT= acetylcholine @ muscarinic receptors  increase K+ efflux   hyperpolarize cell  decrease heart rate b. sympathetic NT= norepinepherine  increase rate of depolarization of SA node  increase heart rate c. total peripheral resistance (TPR)= how hard it is to get blood out to periphery Constrict arteries (vasoconstriction)   increase TPR Dilate arteries (vasodilation)   decrease TPR Total volume of blood is constant in the system Concentrated exercise increases TPR (lifting weights~ biceps curl)
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This note was uploaded on 07/23/2008 for the course BIO 131 taught by Professor Mostman during the Summer '08 term at UCSC.

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Lecture7 - Lecture#7 EKG=(ECG elecrocardiogram(figure 1 p...

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