Transcript Chapter 10: Circulatory System and Lymphatic

UNIT B: Human Body Systems
Chapter 8: Human Organization
Chapter 9: Digestive System
Chapter 10: Circulatory System and
Lymphatic System: Section 10.3
Chapter 11: Respiratory System
Chapter 12: Nervous System
Chapter 13: Urinary System
Chapter 14: Reproductive System
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Chapter 10: Circulatory System and Lymphatic System
Chapter 10: Circulatory System and Lymphatic System
In this chapter, you will learn
about the structure and
function of the circulatory
system and lymphatic
system.
In 2013, Lance Armstrong confessed to long-term blood
doping and the use of banned substances. Blood doping
involves artificially boosting the blood’s ability to bring
more oxygen to muscles. Aerobic capacity and
endurance improve where there are additional red blood
cells available to carry oxygen.
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What is the composition of
blood, including blood cells?
What organs and structures
control the flow of blood
throughout the body?
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
10.3 The Human Heart
The heart is a muscular organ about the size of a fist.
• Myocardium: the major portion of the heart; consists of
cardiac muscle tissue
• Pericardium: a thick membrane within which the heart lies;
secretes lubricating liquid
• Endocardium: the inner surface of the heart; a membrane
composed of connective and endothelial tissue
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Chapter 10: Circulatory System and Lymphatic System
Structure of the Heart
The septum separates the heart into a right
side and a left side.
The heart has four chambers:
• Two upper, thin-walled atria
o Atria fill with blood returning from
the body and lungs
• Two lower, thick-walled ventricles
o Ventricles receive blood from atria
and pump it out to body and lungs
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Structure of the Heart
The heart has four valves that direct the flow of blood
and prevent its backward movement.
• Two atrioventricular valves that are supported by
strong fibrous strings called chordae tendineae
o tricuspid valve: the valve on the right side
o bicuspid (mitral valve): the valve on the left
side
• Two semilunar valves
o pulmonary semilunar valve: lies between right
ventricle and pulmonary trunk
o aortic semilunar valve: lies between the left
ventricle and aorta
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.12 Internal view
of the heart. a. The heart
has four valves. When the
atrioventricular valves open,
blood passes from the atria
to the ventricles, and when
the semilunar valves open,
blood passes out of the
heart.
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.11 External heart
anatomy. a. The venae
cavae and the pulmonary
trunk are attached to the
right side of the heart. The
aorta and the pulmonary
veins are attached to the left
side of the heart.
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.11 External heart
anatomy. b. The coronary
arteries and cardiac veins
pass through cardiac
muscle. The coronary
arteries bring oxygen and
nutrients to cardiac cells,
which derive no benefit from
blood coursing through the
heart. The cardiac veins
drain blood into the right
atrium.
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
Path of Blood through the Heart
•
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The superior vena cava and the inferior vena cava, which
carry O2-poor blood, enter the right atrium.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
• The right atrium sends blood through the tricuspid valve
to the right ventricle.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
• The right ventricle sends blood through the pulmonary
semilunar valve into the pulmonary trunk and through the two
pulmonary arteries to the lungs.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
• Four pulmonary veins, which carry O2-rich blood, enter
the left atrium.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
• The left atrium sends blood through the bicuspid valve to
the left ventricle.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
• The left ventricle sends blood through the aortic semilunar
valve into the aorta and on to the rest of the body.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
• The heart is a double pump.
o Right ventricle sends blood into the lungs
o Left ventricle sends blood into the rest of the body
− A stronger pump, since it has to pump blood to the body
• Cardiac output is the volume of blood that the left ventricle
pumps per minute.
o Cardiac output is about 5.25 L of blood per minute in a
person with an average heart rate of 70 beats per minute
• The pulse is a wave effect that passes down the walls of the
arteries when the aorta expands and recoils with each ventricular
contraction; can be used to determine heart rate
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
The Heartbeat
Each heartbeat is called a cardiac cycle. When a heart beats:
• The two atria contract at the same time, and the ventricles
are relaxed and fill with blood
• Then, the two ventricles contract at the same time
• Then, all the chambers relax
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.13 Generation
of heart sounds during
the cardiac cycle.
a. When the atria
contract, the ventricles
are relaxed and filling
with blood.
b. When the ventricles
contract, the
atrioventricular valves
close, preventing blood
from flowing back into the
atria and producing the
“lub” sound of the
heartbeat.
c. After the ventricles
contract, the “dub ” sound
of the heartbeat results
from the closing of the
semilunar valves to
prevent arterial blood
from flowing back into the
ventricles.
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
The heart beats about 70 times a minute; each heartbeat is 0.85 s.
• Systole is the contraction of the heart muscle
• Diastole is the relaxation of the heart muscle
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Chapter 10: Circulatory System and Lymphatic System
Intrinsic Control of Heartbeat
The heart is able to contract and relax
rhythmically due to the presence of nodal
tissue, a type of cardiac muscle.
Nodal tissue is located in two areas::
• SA (sinoatrial) node: initiates the
heartbeat and sends out an impulse
every 0.85 s; also called the pacemaker
• AV (atrioventricular) node: transmits an
impulse through specialized cardiac
muscle fibres called the atrioventricular
bundle (AV bundle), which send the
signal to Purkinje fibres
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.14 Conduction
system of the heart.
a. The SA node sends out a
stimulus (black arrows), which
causes the atria to contract.
When this stimulus reaches the
AV node, it signals the
ventricles to contract. Impulses
pass down the two branches of
the atrioventricular bundle to the
Purkinje fibres, and thereafter
the ventricles contract.
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
Extrinsic Control of Heartbeat
The body also has extrinsic ways to regulate the heartbeat.
Medulla oblongata (portion of the brain that controls internal organs)
• Can alter heartbeat by the autonomic nervous system
o Parasympathetic: decreases SA and AV nodal activity when
inactive
o Sympathetic: increases SA and AV nodal activity when active
Epinephrine and norepinephrine (hormones)
• Released by the adrenal medulla
• Heart pumps faster and stronger due to sympathetic stimulation
and release of epinephrine and norepinephrine
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Chapter 10: Circulatory System and Lymphatic System
The Electrocardiogram
An electrocardiogram (ECG) is a recording of the electrical
changes that occur in the myocardium during a cardiac cycle.
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Figure 10.14 Conduction system of the heart. b. A normal ECG usually
indicates that the heart is functioning properly. The P wave occurs just before
atrial contraction; the QRS complex occurs just before ventricular contraction;
and the T wave occurs when the ventricles are recovering from contraction.
Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
Different types of abnormalities, known as arrhythmias can be
detected by an ECG
• Atrial fibrillation (AF): multiple, chaotic impulses are
generated from the AV node, causing an irregular, fast
heartbeat
• Ventricular fibrillation (VF): uncoordinated contraction of the
ventricles; can occur after a heart attack, injury, or drug
overdose
o Heart in VF is not pumping blood and must be defibrillated
by applying an electrical current to reestablish heartbeat
o Automatic external defibrillators(AEDs) can be used to
administer an electrical current to the chest
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.14 Conduction
system of the heart.
b. A normal ECG .
c. Ventricular fibrillation
produces an irregular
electrocardiogram due to
irregular stimulation of the
ventricles.
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Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
Check Your Progress
1. Name each blood vessel and heart chamber that blood
passes through on its journey through the heart and
lungs.
2. Predict what might happen to the lungs if the left
ventricle was not able to pump blood properly.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
Check Your Progress
3. Describe the specific cause of each sound of the
heartbeat.
4. Explain why it is important for the speed and strength
of heart contractions to be regulated both intrinsically
and extrinsically.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3
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Chapter 10: Circulatory System and Lymphatic System
Section 10.3