Anatomy Physiology SIXTH EDITION Chapter 20 part 4

Anatomy & Physiology SIXTH EDITION Chapter 20, part 4 The Heart Power. Point® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Frederic H. Martini Fundamentals of

Factors Affecting Heart Rate • Autonomic innervation • Cardiac reflexes • Tone • SA node • Hormones • Epinephrine (E), norepinephrine(NE), and thyroid hormone (T 3) • Venous return Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 20. 20 Factors Affecting Cardiac Output Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 20

Medulla Oblongata centers affect autonomic innervation • Cardioacceleratory center activates sympathetic neurons • Cardioinhibitory center controls parasympathetic neurons • Receives input from higher centers, monitoring blood pressure and dissolved gas concentrations Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 20. 21 Autonomic Innervation of the Heart Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 21

Figure 20. 21 Autonomic Innervation of the Heart Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 21

Basic heart rate established by pacemaker cells • SA node establishes baseline • Modified by ANS • Atrial reflex Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 20. 22 Pacemaker Function Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 22

Figure 20. 22 Pacemaker Function Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 22

Factors Affecting stoke volume • EDV • Frank-Starling principle • ESV • Preload • Contractility • Afterload Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 20. 23 Factors Affecting Stroke Volume Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 23

Figure 20. 23 Factors Affecting Stroke Volume Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 23

Autonomic Activity • Sympathetic stimulation • Positive inotropic effect • Releases NE • Parasympathetic stimulation • Negative inotropic effect • Releases ACh Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Exercise and Cardiac Output • Heavy exercise can increase output by 300 -500 percent • Trained athletes may increase cardiac output by 700 percent • Cardiac reserve • The difference between resting and maximal cardiac output PLAY Animation: Cardiac cycle Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Summary: Regulation of Heart Rate and Stroke Volume • Sympathetic stimulation increases heart rate • Parasympathetic stimulation decreases heart rate • Circulating hormones, specifically E, NE, and T 3, accelerate heart rate • Increased venous return increases heart rate • EDV is determined by available filling time and rate of venous return • ESV is determined by preload, degree of contractility, and afterload Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 20. 24 A Summary of the Factors Affecting Cardiac Output Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 20. 24

SECTION 20 -5 The Heart and the Cardiovascular System Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

The heart is part of the cardiovascular system • The goal of the cardiovascular system is to maintain adequate blood flow to all body tissues • The heart works in conjunction with cardiovascular centers and peripheral blood vessels to achieve this goal Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

You should now be familiar with: • The organization of the cardiovascular system. • The location and general features of the heart, including the pericardium. • The differences between nodal cells and conducting cells as well as the components and functions of the conducting system of the heart. • The electrical events associated with a normal electrocardiogram. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

You should now be familiar with: • The events of the cardiac cycle including atrial and ventricular systole and diastole, and the heart sounds related to specific events in the cycle. • Cardiac output, heart rate and stroke volume and the factors that influence these variables. • How adjustments in stroke volume and cardiac output are coordinated at different levels of activity. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings