1. 9 November 2009 Cardiovascular Physiology
Lab this Week: Human EKGs, Heart Sounds, and Blood Pressure…
Wear running shoes, comfortable clothes, bring calculator & textbook.
Abstracts due Friday at start of Class.

2. Cardiac Output = Heart Rate X Stroke Volume CO = HR x SV 5L/min = 72 beat/min x 70 ml/beat

3. Figure 12.07 Tricuspid Bicuspid =Mitral 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)
Figure 12.07
Bicuspid =Mitral
Tricuspid
Heart sounds and valve closings
Semilunar Valves

4. SA node cells spontaneously produce AP, do not have stable resting membrane potential, are Pacemaker cells
Figure 12.11

5. Intercalated Discs: mechanical attachments of cardiac myofibers to each other, with gap junctions (electrical synapses) to conduct AP

6. Figure 12.13 Cardiac Myofiber Plateau phase
Cardiac Myofiber action potential
Long refractory period prevent summation in cardiac myofibers
Cardiac Myofiber

7. Figure 12.17
Calcium-induced calcium release

8. 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.

9. Pacemaker Cells in Conducting System
Figure 12.14
Pacemaker Cells in Conducting System
SA Node or Bundle of His
Ectopic Pacemaker
Location other than SA Node

10. Figure 12.22
Intrinsic Rate = 100 beat/min

11. Effect of “Beta blockers”
Figure 12.23 NE
EPI
ACh
mAChR
Beta-adrenergic receptors
Effect of “Beta blockers”
Effect of atropine

12. Who Cares? Mechanism of action of a Ca++ channel blocker?
What effect on blood pressure?

13. Figure 12.18
1st Heart Sound = Closure of Atrioventricular (AV) valves at beginning of Ventricular Systole
2nd Heart Sound = Closure of Semilunar valves at beginning of Ventricular Diastole

14. Ventricular Fibrillation & Defibrillation
Figure 12.20
Systolic
Diastolic
Atrial Fibrillation
Ejection Fraction = SV/EDV
Ventricular Fibrillation & Defibrillation