31 October 2011 Ch 12 Cardiovascular Physiology 6

31 October 2011 Ch 12 Cardiovascular Physiology 6 sections p. 353 -433 2 CV labs: 1 Frog heart, 1 Human EKG and Blood Pressure

1 QQ # 23 for 8: 30 & 9: 30 • In one or two sentences, summarize your results from your abstract. What did you find and does it seem to make sense?

S 1 Cardiac Output = Heart Rate X Stroke Volume What regulates heart rate? What regulates Stroke Volume? CO = HR x SV 5 L/min = 72 beat/min x 70 ml/beat The Cardiac Cycle animation

Problems with valves: Heart murmurs ≠ heart sounds …. Stenosis (narrowing) →Heart Murmurs (turbulent flow past a constriction) Figure 12. 07 note: origin of neonatal heat murmurs (foramen ovale) …. Prolapse (eversion) allows backflow (also generates murmurs) S 4 Bicuspid =Mitral Tricuspid Heart sounds produced by valve closings Semilunar Valves Animation

S 3 Cardiac Myofiber action potential Cardiac Myofiber Figure 12. 13 Plateau phase Long refractory period prevents summation in cardiac myofibers

S 4 Figure 12. 11 S 5 SA node cells do not have stable resting membrane potential, spontaneously produce AP, are Pacemaker cells

S 5 Cardiac Pacemaker action potential Figure 12. 14 Ectopic Pacemaker Cells in Conducting System: SA Node and Bundle of His Locations other than SA Node These cells set the rhythm & control Heart Rate.

S 15 Figure 12. 22 Intrinsic Rate = 100 beat/min 2 effects of Parasymp: hyperpolarization & slower depolarization

S 6 Figure 12. 23 NE Beta-adrenergic receptors Effect of “Beta blockers” EPI ACh m. ACh. R Effect of atropine

S 7 What prevents the AP from being conducted from ventricles back to atria? Fibrous connective tissue between atria and ventricles prevents the conduction of action potential. Only route is via AV node, bundle of His, bundle branches, Purkinje fibers, and to ventriclular myofibers.

S 8 “Sis-toe-lee” 1 st Heart Sound = Closure of Atrioventricular (AV) valves at beginning of Ventricular Systole “die-ass-toe-lee” 2 nd Heart Sound = Closure of Semilunar valves at beginning of Ventricular Diastole

S 9 Figure 12. 20 Systolic Diastolic Atrial Fibrillation Stroke Volume Ejection Fraction = SV/EDV Ventricular Fibrillation & Defibrillation Animation

S 10 Events are same for Cardiac Cycle for Right Side of Heart; only difference is lower systolic pressures in right atrium and right ventricle.