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

1QQ # 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?

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

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

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

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

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

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

Figure Effect of “Beta blockers” NEEPIACh mAChR Effect of atropine Beta-adrenergic receptors S 6

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. What prevents the AP from being conducted from ventricles back to atria? S 7

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

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

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