Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 14, part B Cardiovascular Physiology

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pacemaker membrane potential I-f channels Na + influx Ca++ channels – influx, to AP Slow K + open – repolarization Autorhythmic Cells: Initiation of Signals PLAY Animation: Cardiovascular System: Cardiac Action Potential

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Autorhythmic Cells: Initiation of Signals Figure 14-16: Action potentials in cardiac autorhythmic cells

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sympathetic – speeds heart rate by  Ca++ & I-f channel flow Parasympathetic – slows rate by  K+ efflux &  Ca++ influx Sympathetic and Parasympathetic Figure 14-17: Modulation of heart rate by the nervous system

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings AP from autorhythmic cells in sinoatrial node (SA) Spreads via gap junctions down internodal pathways and across atrial myocardial cells (atrial contraction starts) Pause – atrioventricular (AV) node delay AV node to bundles of His, branches & Perkinje fibers Right and left ventricular contraction from apex upword Coordinating the Pump: Electrical Signal Flow

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Coordinating the Pump: Electrical Signal Flow Figure 14-18: Electrical conduction in myocardial cells

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Coordinating the Pump: Electrical Signal Flow PLAY Animation: Cardiovascular System: Intrinsic Conduction System Figure 14-19a: Electrical conduction in the heart

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Electrocardiogram (ECG): Electrical Activity of the Heart Figure 14-20: Einthoven’s triangle Einthoven's triangle P-Wave – atria QRS- wave – ventricles T-wave – repolarization

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Electrocardiogram (ECG): Electrical Activity of the Heart Figure 14-21: The electrocardiogram

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings (Non-invasive) Heart Rate Signal conduction Heart tissue Conditions ECG Information Gained Figure 14-24: Normal and abnormal electrocardiograms

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Heart Cycle: Heart Chambers and the Beat Sequence PLAY Animation: Cardiovascular System: The Cardiac Cycle 1. Late diastole: all chambers relax, filling with blood 2. Atrial systole: atria contract, add 20% more blood to ventricles 3. Isovolumic ventricular contraction: closes AV valves ("lub"), builds pressure

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 4. Ventricular ejection: pushes open semi lunar valves, blood forced out 5. Ventricular relaxation: aortic back flow slams semi lunar valves shut ("dup") AV valves open refilling starts – back to start of cycle Heart Cycle: Finish and Around To the Start

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Heart Cycle Figure 14-25: Mechanical events of the cardiac cycle

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Summary of Heart Beat: Electrical, Pressure and Chamber Volumes Figure 14-27: The Wiggers diagram

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Range: about 50 – near 200 Typical resting: near 70 AP conduction Muscle Contraction Parasympathetic slows Sympathetic speeds Regulators of the Heart: Reflex Controls of Rate

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regulators of the Heart: Reflex Controls of Rate Figure 14-28: Reflex control of heart rate

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Around 5L : (72 beats/m  70 ml/beat = 5040 ml) Rate: beats per minute Volume: ml per beat EDV - ESV Residual (about 50%) Cardiac Output: Heart Rate X Stroke Volume PLAY Animation: Cardiovascular System: Cardiac Output

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Output: Heart Rate X Stroke Volume Figure 14-26: The Wiggers diagram

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Starlings Law – stretch Force of contraction Venous return: Skeletal pumping Respiratory pumping Regulators of the Heart: Factors Influencing Stroke Volume

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regulators of the Heart: Factors Influencing Stroke Volume Figure 14-29: Length-force relationships in the intact heart

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regulators of the Heart: Factors Influencing Stroke Volume Figure 14-31: Factors that affect cardiac output

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy and physiology of the Heart, its chambers, muscles, valves, and its pacemaker Mechanism of cardiac muscle stimulation and contraction Blood vessels and fluid flow down a pressure gradient Electrical control of the beat sequence, and ECG information Influence of beat rate and stroke volume by ANS and hormones Summary