Download Chapter 6 Cardiovascular System

CHAPTER 7
CARDIOVASCULAR SYSTEM
BEHAVIORAL OBJECTIVES
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Describe the structure and function of arteries, capillaries, and veins. [7.1, pp.126-127; Fig. 7.2]
Explain how blood flow may bypass certain capillary beds. [7.1, p.127; Fig. 7.3]
Describe external heart anatomy. [7.1, p. 128; Fig. 7.4]
Trace the path of blood flow through the heart. [7.2, pp.128-129; Fig. 7.5]
Name the heart’s chambers and valves and their functions. [7.2, pp.128-129; Fig. 7.5]
Describe sequence of contractions in the cardiac cycle. [7.2, p.130; Fig. 7.6]
Explain how the conduction system of the heart controls the heartbeat. [7.2, p.130; Fig. 7.7]
Describe how impulses from the nervous system and hormones control the heart rate. [7.2, p.131]
Identify the factors that influence blood pressure. [7.3, pp.132-133; Fig. 7.10]
Describe how a sphygmomanometer is used to measure blood pressure and the normal resting blood pressure
of a young adult. [7.3, p.132; Fig. 7.9]
Describe the forces that return blood to the heart through the veins. [7.3, p.133; Fig. 7.11]
Name and locate on a drawing the major arteries and veins. [7.4, pp.134-135; Fig. 7.12 & 7.13]
Identify the major vessels of the pulmonary circuit and describe pulmonary circulation. [7.4, p.134; Fig. 7.5b,
Fig. 7.12]
Identify the major vessels of the systemic circuit and describe systemic circulation. [7.4, p.135; Fig. 7.12, Fig.
7.13]
Describe what makes the hepatic portal system unique. [7.4, p.135; Fig. 7.11]
Discuss the factors that can lead to cardiovascular disorders and how they can be prevented. [7.5, pp.136-139;
Fig. 7A; Health Focus]
Describe the role of the circulatory system in homeostasis. [7.6, pp. 139-140]
Discuss how the circulatory system works with other body systems to maintain homeostasis. [7.6, p.140;
Human Systems Work Together]
Understand and use the bold-faced and italicized terms included in this chapter. [Understanding Key Terms,
p.143]
EXTENDED LECTURE OUTLINE
7.1 The Blood Vessels
The Arteries
Arteries and arterioles take blood away from the heart. The middle layer of arteries consists of smooth muscle that
can constrict to regulate blood flow and blood pressure.
The Capillaries
The capillaries with walls that are only one cell thick allow exchange of substances with tissue fluid. Not all
capillary beds are open at the same time. Contraction of a sphincter muscle closes off the bed and then blood flows
through an arteriovenous shunt by-passing the capillary bed.
The Veins
Venules drain into veins that take blood to the heart. Veins have much less smooth muscle and connective tissue
than an artery. Veins often have values that prevent the backward flow of blood when closed.
Mader VRL CD-ROM
Image 0134l.jpg (Fig. 7.1)
Image 0135l.jpg (Fig. 7.2)
Image 0136l.jpg (Fig. 7.3)
Dynamic Human CD-ROM
Cardiovascular/Histology/Arteriole
Cardiovascular/Histology/Elastic Artery
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Dynamic Human CD-ROM, con’t.
Cardiovascular/Histology/Medium-Sized Vein
Life Science Animations VRL 2.0
Cardiovascular/Histology/Vasculature
Animal Biology/Circulatory System/ Capillary Bed
Transparencies
97 (Fig. 7.2a, b, c)
98 (Fig. 7.3)
7.2 The Heart
The cone-shaped, muscular heart is made up of myocardium lying inside a fibrous pericardium. Coronary arteries
supply the myocardium with oxygen and nutrients. In the heart the right and left atria empty into the right and left
ventricles respectively. Atrioventricular valves occur between the atria and ventricles and semilunar valves occur
between the ventricles and the attached arteries.
Passage of Blood Through the Heart
This sequence traces the path of blood through the heart: superior and inferior vena cava, right atrium, right
ventricle, pulmonary arteries to the lungs. Pulmonary veins, left atrium, left ventricle, aorta.
The Heartbeat
Each heartbeat is called a cardiac cycle. Systole refer to the contraction of heart chambers and diastole refers to
their relaxation. The heart sounds, lub-dup, are due to the closing of the atrioventricular valves, followed by the
closing of the semilunar valves. The surge of blood enter the arteries results in pulse.
Intrinsic Control of Heartbeat
The SA node (pacemaker) initiates the beat and causes the atria to contract. The AV node conveys the
stimulus and initiates contraction of the ventricles. The signal for the ventricles to contract travels from
the AV node through the atrioventricular bundle to the smaller Purkinje fibers.
Extrinsic Control of Heartbeat
A cardiac control center in the medulla oblongata regulates the heartbeat by way of the parasympathetic
(slow heart beat) and the sympathetic (increases heart beat) systems
The Electrocardiogram
An electrocardiogram (ECG) is a recording of the electrical changes that occur in myocardium during a cardiac
cycle. The P wave signals the atria are about to contract; the QRS wave signals the ventricles are about to
contract, and recovery of the ventricles produces the T wave.
Mader VRL CD-ROM
Image 0137al.jpg (Fig. 7.4)
Image 0137bl.jpg (Fig. 7.4)
Image 0137cl.jpg (Fig. 7.4)
Image 0137dl.jpg (Fig. 7.4)
Image 0138al.jpg (Fig. 7.5)
Image 0138bl.jpg (Fig. 7.5)
Image 0138cl.jpg (Fig. 7.5)
Image 0138dl.jpg (Fig. 7.5)
Image 0139l.jpg (Fig. TA7.1)
Image 0140l.jpg (Fig. 7.6)
Image 0141l.jpg (Fig. 7.7)
Dynamic Human CD-ROM
Cardiovascular/Anatomy/3D Viewer
Cardiovascular/Anatomy/Gross Anatomy
Cardiovascular/Clinical Concepts/Electrocardiogram
Cardiovascular/Explorations/Heart Dynamics
Cardiovascular/Histology/Cardiac Muscle
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Dynamic Human CD-ROM, con’t.
Cardiovascular/Histology/Purkinje Fibers
Life Science Animations VRL 2.0
Animal Biology/Circulatory System/ Path of Blood
Animal Biology/Circulatory System/Cardiac Conduction
System
Animal Biology/Circulatory System/ Electrical Activity of the
Heart
Animal Biology/Circulatory System/ Cardiac Cycle Blood Flow
(Normal Speed)
Animal Biology/Circulatory System/ Cardiac Cycle Blood Flow
(Slow Motion)
Animal Biology/Circulatory System/ Cardiac Cycle Electrical
Animal Biology/Circulatory System/ Cardiac Cycle Muscular
Animal Biology/Circulatory System/ Cardiac Cycle Sounds
Animal Biology/Circulatory System/ Cardiac Cycle Sounds
(Detail)
Mader ESP Modules Online
Transparencies
Animals/Transport/Human Heart
99 (Fig. 7.4a)
100 (Fig. 7.4b)
101 (Fig. 7.5a)
102 (Fig. 7.5b)
103 (Fig. 7.6)
104 (Fig. 7.7)
7.3 Features of the Cardiovascular System
Pulse
The surge of blood entering the arteries following a heartbeat causes their elastic walls to stretch and then recoil.
This is felt as a pulse. The pulse rate of the radial and carotid artery tells the heartbeat rate.
Blood Flow
Blood Flow in Arteries
Blood pressure due to the pumping of heart accounts for the flow of blood in the arteries. Both systolic
and diastolic blood pressures decrease with distance from the left ventricle because blood enters more and
more arterioles and arteries.
Blood Flow in Capillaries
Blood moves slowly in capillaries because there are more capillaries than arterioles.
Blood Flow in Veins
Venous return is dependent upon: skeletal muscle contraction, presence of valves in veins, and respiratory
movements. Once blood has moved past a valve it closes preventing backward return.
Mader VRL CD-ROM
Image 0142l.jpg (Fig. 7.8)
Image 0143l.jpg (Fig. 7.9)
Image 0144l.jpg (Fig. 7.10)
Image 0145l.jpg (Fig. 7.11)
Mader ESP Modules Online
Animals/Transport/Vessels and Pressure
Transparencies
105 (Fig. 7.8)
106 (Fig. 7.9)
107 (Fig. 7.10)
108 (Fig. 7.11)
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7.4 The Vascular Pathways
The Pulmonary Circuit
In the pulmonary circuit, two pulmonary arteries take blood from the right ventricle to the lungs, and four
pulmonary veins return it to the left atrium.
The Systemic Circuit
To trace the path of blood in the systemic circuit, start with the aorta from the left ventricle. Follow its path until it
branches to an artery going to a specific organ. It can be assumed that the artery divides into arterioles and
capillaries, and that the capillaries lead to venules. The vein that takes blood to the vena cava most likely has the
same name as the artery that delivered blood to the organ. In the adult systemic circuit, unlike the pulmonary
circuit, the arteries carry blood that is relatively high in oxygen and relatively low in carbon dioxide, and the veins
carry blood that is relatively low in oxygen and relatively high in carbon dioxide.
Mader VRL CD-ROM
Image 0146l.jpg (Fig. 7.12)
Image 0147al.jpg (Fig. 7.13)
Image 0147bl.jpg (Fig. 7.13)
Image 0147cl.jpg (Fig. 7.13)
Dynamic Human CD-ROM
Cardiovascular/Anatomy/Gross Anatomy
Cardiovascular/Explorations/General Vasculature
Cardiovascular/Explorations/Portal System
Life Science Animations VRL 2.0
Animal Biology/Circulatory System/ Path of Blood
Transparencies
109 (Fig. 7.12)
110 (Fig. 7.13)
7.5 Cardiovascular Disorders
Prevention of cardiovascular disorders includes a heart-healthy diet, getting regular exercise, maintaining a proper
weight, and not smoking cigarettes.
Hypertension
Hypertension is high blood pressure, which can lead to heart disease. The best defense against hypertension is a
life-style that lowers the risk of hypertension.
Atherosclerosis
Atheroclerosis is due to a build-up of plaque in arterial walls. Plaque can lead to thromboembolism.
Stroke, Heart Attack, and Aneurysm
If a blood clot lodges in a cerebral blood vessel or a cerebral blood vessel bursts, a stroke has occurred and a
portion of the brain dies. If a blood clot lodges in a coronary blood vessel, a heart attack occurs. An aneurysm is a
ballooning of a blood vessel. If a major blood vessel like the aorta bursts, death is likely.
Dissolving Blood Clots
There are medical treatments for dissolving and perhaps preventing the occurrence of blood clots.
Coronary Bypass Operation
During this operation, a vessel is grafted onto the heart to bypass an obstructed vessel.
Clearing Clogged Arteries
Angioplasty is a common surgical procedure for treating clogged arteries.
Heart Transplants and Other Treatments
Heart transplants are routinely performed but immunosuppressive drugs must be taken thereafter. Work
still goes forward on an artificial heart.
Dilated and Inflamed Veins
Varicose veins develop when the valves of veins become weak and ineffective. Hemorrhoids are due to varicose
veins in the rectum. Phlebitis, inflammation of a vein, can lead to a blood clot and possible death.
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Mader VRL CD-ROM
Image 0148l.jpg (Fig. 7A)
Image 0149l.jpg (Fig. 7.14)
Image 0150l.jpg (Fig. 7.15)
Dynamic Human CD-ROM
Life Science Animations VRL 2.0
Cardiovascular/Clinical Concepts/Heart Murmur
Cardiovascular/Clinical Concepts/Myocardial Infarction
Animal Biology/Circulatory System/ Myocardial Infarction
Animal Biology/Circulatory System/ Portal System
Animal Biology/Circulatory System/ Valvular Stenosis
Animal Biology/Circulatory System/ Valvular Insufficiency
Case Studies Online
Heart Transplant
Transparencies
111 (Fig. 7.14)
112 (Fig. 7.15)
7.6 Homeostasis
In general the cardiovascular system contributes to homeostasis by supplying the tissues with nutrient molecules
and oxygen. A Human Systems Work Together box shows how the cardiovascular system works with other
systems in the body to maintain homeostasis.
Mader VRL CD-ROM
Image 0151al.jpg (Fig. TA7.2)
Image 0151bl.jpg (Fig. TA7.2)
Image 0152l.jpg (Fig. 7B)
Image 0153l.jpg (Fig. TA7.3)
Transparencies
113 (Fig. TA7.1)
114 (Fig. TA 7.2)
SEVENTH EDITION CHANGES
New/Revised Text:
This was chapter 6 in the previous edition. Throughout the chapter and entire text, the terms “O2-rich”
and “O2-poor” replace the phrases “high in oxygen” and oxygenated” and “low in oxygen” or “deoxygenated.”
7.4 The Vascular Pathways. The path of blood to and from the lower legs has been corrected and now
includes the femoral artery, lower leg capillaries, and femoral vein.
7.6 Homeostasis. The end of the chapter has been repaged so that The Working Together page does not
interrupt the end matter.
New/Revised Figures:
7.5 Internal view of the heart; 7.6 Stages in the cardiac cycle; 7.7 Conduction system of the heart
STUDENT ACTIVITIES
Conditioning and pulse rate
1. Ask for student volunteers and compare the resting heart rates of several students in the class. Next, ask these
students to briskly walk up and down two flights of stairs. This exercise shows the relationship between how
well resting pulse correlates to overall physical conditioning (ask students how often they exercise and for
how long to estimate physical conditioning).
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Prevention of Cardiovascular Disease
2. Students should read the Health Focus, “Prevention of Cardiovascular Disease,” before coming to class.
Students are to develop a profile of the individual who is most likely to have a heart attack: smokes cigarettes,
drinks alcohol, is obese, is a couch potato, and eats fatty foods. The drugs used to lower cholesterol may
damage the liver. Students are to consider whether relying on drugs or modifying one’s behavior is a better
solution. Let students debate whether behavior modification is worth the effort to prevent heart attacks.
Mammalian Heart Structure
3. Dissect a fresh beef or pork heart as a demonstration to your class. Butchers will often donate materials for
educational use if you contact them in advance. Request that they leave the major blood vessels intact.
Demonstrate the features of the hearts to your students. This is an opportunity to relate form with function as
you show the varying thicknesses of ventricle walls. Point out valves, and “heartstrings” (chordae tendineae),
and semilunar valves.
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