Download 20-04_pptlect

Anatomy & Physiology
SIXTH EDITION
Chapter 20, part 4
The Heart
PowerPoint® 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 (T3)
• 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
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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
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Figure 20.22
Figure 20.22 Pacemaker Function
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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 T3,
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