Transcript BCBio12_Chapter10_Section10.4

UNIT B: Human Body Systems
Chapter 8: Human Organization
Chapter 9: Digestive System
Chapter 10: Circulatory System and
Lymphatic System: Section 10.4
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
10.4 The Vascular Pathways
The circulatory system includes
two circuits.
• Pulmonary circuit: circulates
blood through the lungs
• Systemic circuit: circulates
blood to the body tissues
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.15 Path of blood.
This symbolic and not-to-scale
drawing shows the path of blood
in the pulmonary and systemic
circuits. The pulmonary arteries
and veins take blood from the
right (blue) to the left (red) side
of the heart. Tracing blood from
the digestive tract to the right
atrium in the systemic circuit
involves the hepatic portal vein,
the hepatic vein, and the inferior
vena cava. The blue-coloured
vessels carry O2-poor blood,
and the red-coloured vessels
carry O2-rich blood; the arrows
indicate the direction of blood
flow.
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Section 10.4
The Pulmonary Circuit
Pulmonary circuit: circulates blood to lungs
• Blood from all regions of the body first
collects in the right atrium.
• Blood passes into the right ventricle,
which pumps it into the pulmonary trunk.
• Pulmonary trunk divides into right and
left pulmonary arteries, which branch
into arterioles.
• Arterioles take blood to the pulmonary
capillaries, where gas exchange occurs.
• Blood passes through pulmonary
venules, which lead to pulmonary veins
that enter the left atrium.
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Chapter 10: Circulatory System and Lymphatic System
The Systemic Circuit
Systemic circuit: circulates blood
to body tissues.
• The aorta and venae cavae
serve as the major pathways
for blood in the systemic
circuit
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
The path of systemic blood to any
organ in the body begins in the left
ventricle.
Trace the path of blood to and from
the legs:
• left ventricle  aorta  common
iliac artery  femoral artery 
leg capillaries  femoral vein 
common iliac vein  inferior
vena cava  right atrium
Figure 10.16 Major arteries (red) and veins (blue) of the systemic
circuit. This representation of the major blood vessels of the
systemic circuit shows how the systemic arteries and veins are
arranged in the body. The superior and inferior venae cavae take
their names from their relationship to which organ?
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Section 10.4
Blood Pressure
As blood passes through the blood vessels in the body, it exerts
pressure against the vessel walls (blood pressure).
• Systolic pressure: results from blood being forced into arteries
when ventricles contract (ventricular systole)
• Diastolic pressure: results from pressure in the arteries when
ventricles fill with blood (ventricular diastole)
o Blood pressure can be measured with a sphygmomanometer,
which has a pressure cuff that determines the amount of
pressure required to stop the flow of blood through an artery
o Expressed in millimetres of mercury as a fraction of systolic
pressure over diastolic pressure (e.g., 120/80 mm Hg)
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Chapter 10: Circulatory System and Lymphatic System
Blood pressure decreases as
blood flows from the aorta
into the arteries, arterioles,
and capillaries.
• Blood is under minimal
pressure in capillaries
since capillaries have a
high total cross-sectional
area.
Figure 10.17 Blood velocity and
blood pressure. In capillaries, blood
is under minimal pressure and has
the least velocity. Blood pressure and
velocity drop off because capillaries
have a greater total cross-sectional
area than arterioles.
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Blood pressure in the veins is low.
• Valves prevent the backward
flow of blood in veins, and
muscle contraction is sufficient
to move blood toward the heart.
Figure 10.18 Cross section of a valve in a
vein. a. Pressure on the walls of a vein,
exerted by skeletal muscles, increases blood
pressure within the vein and forces the valve
open.
b. When external pressure is no longer applied
to the vein, blood pressure decreases, and
back pressure forces the valve closed. Closure
of the valve prevents the blood from flowing in
the opposite direction.
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Check Your Progress
1. Identify which arteries carry O2-poor blood.
2. Name the major blood vessels through which blood
flows to the lungs and other parts of the body.
3. Describe blood flow in an artery versus a vein.
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Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Section 10.4
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Chapter 10: Circulatory System and Lymphatic System
Section 10.4