1. 11 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 12.23 NEEPIACh mAChR Beta-adrenergic receptors

4. Figure 12.18 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

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

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

7. Frank-Starling Law of the Heart FS LoH = SV is proportional to EDV Ventricular Function Curve Does not depend on hormones or nerves Assures that the heart adjusts its output based on VENOUS RETURN Ways to enhance Venous Return: 1) muscle contractions 2) “respiratory pump” 3) venoconstriction

8. Fig. 09.21 Low EDV High EDV Length-tension “curve” for Cardiac muscle Overinflation of ventricles leads to less effective pumping

9. Overinflation of ventricles results in reduction in stroke volume

10. Figure 12.25 Contractility NE from Symp postganglionics & EPI from Adrenal medulla Note: cardiac myofibers NOT innervated by parasympathetic division Increase Ejection Fraction

11. 3 Effects of Sympathetic Stimulation 1: Increase rate of contraction 2: Increase peak tension 3: Decrease twitch duration

12. Control of Stroke Volume End diastolic volume (preload) Contractility (strength of ventricular contraction due to adrenergic stimulation) Afterload (pressure in arteries that must be overcome) FS LoH

13. Afterload is analogous to trying to pump more air into a tire that is already fully inflated (heart contracting to overcome diastolic pressure.) How is afterload affected if diastolic pressure is 60 mmHg? High blood pressure increases the workload of the heart….. Cardiac hypertrophy….increase chance of irregular conduction of AP through heart

14. CO = HR x SV 5L/min = 72 beat/min x 70 ml/beat 35 L/min = ? beat/min x ? ml/beat