Transcript Fetal Circulation

UNIT B: Human Body Systems
Chapter 8: Human Organization
Chapter 9: Digestive System
Chapter 10: Circulatory System and
Lymphatic System: Section 10.5
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 10.5
10.5 Fetal Circulation
The fetus has circulatory features not present in adult circulation.
These are necessary since the lungs are not functional in the fetus.
• Blood passes directly from the right atrium to the left atrium
through the foramen ovale between the atria.
• Any blood that does not enter the right ventricle and is pumped
into the pulmonary trunk is shunted into the aorta by the ductus
arteriosus.
• Umbilical arteries take fetal blood to the placenta, where the
exchange of gases and nutrients between maternal blood and
fetal blood takes place.
• The umbilical vein then carries the nutrient and O2-rich blood
to the fetus.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.5
Figure 10.19 Fetal circulation. The
lungs are not functional in the fetus,
and the blood passes directly from the
right atrium to the left atrium or from
the right ventricle to the aorta. The
umbilical arteries take fetal blood to
the placenta, and the umbilical vein
returns fetal blood from the placenta.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.5
Structure and Function of the Placenta
The placenta is attached to the uterine wall by the allantois
and chorionic villi.
• Functions only before birth; becomes part of the afterbirth
when child is born
• Involved in gas, nutrient, and waste exchange between the
fetal and maternal circulatory systems
• Umbilical cord contains the umbilical arteries and vein,
which transport waste to the placenta, and take oxygen
and nutrients to the fetal circulatory system
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.20 The Placenta. At the placenta, an exchange of molecules
between fetal and maternal blood takes place across the walls of the
chorionic villi. Oxygen and nutrient molecules diffuse into the fetal blood,
and carbon dioxide and urea diffuse out of the fetal blood.
Section 10.5
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Chapter 10: Circulatory System and Lymphatic System
Section 10.5
Check Your Progress
1. Describe the path of blood flow in the fetus, and name
the structures unique to fetal circulation.
2. Explain the function of the placenta.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.5