Ch. 28 Pregnancy and Human Development
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 1 The Human Body: An Orientation25
- Ch. 2 Chemistry Comes Alive24
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System12
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton14
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System25
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System25
- Ch. 13 The Peripheral Nervous System and Reflex Activity30
- Ch. 14 The Autonomic Nervous System16
- Ch. 15 The Special Senses26
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart25
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses27
- Ch. 22 The Respiratory System21
- Ch. 23 The Digestive System31
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System26
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System24
- Ch. 28 Pregnancy and Human Development25
- Ch. 29 Heredity11
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
Chapter 28, Problem 6
Which of the following changes occur in the baby’s cardiovascular system after birth?
(a) umbilical arteries and vein become fibrosed
(b) pulmonary circulation begins to function, and pressure in the left side of the heart increases
(c) the ductus venosus becomes obliterated, as does the ductus arteriosus
(d) all of these
Verified step by step guidance1
Step 1: Understand the fetal circulation system before birth, which includes structures like the umbilical arteries and vein, ductus venosus, and ductus arteriosus that help bypass the lungs and liver since the fetus gets oxygen from the placenta.
Step 2: Recognize that after birth, the baby starts breathing air, so the lungs expand and pulmonary circulation begins to function, increasing blood flow to the lungs and raising pressure on the left side of the heart.
Step 3: Know that the umbilical arteries and vein, which carried blood to and from the placenta, close and become fibrosed (turn into fibrous tissue) since the placenta is no longer needed for oxygen exchange.
Step 4: Understand that the ductus venosus (which shunted blood away from the liver) and the ductus arteriosus (which connected the pulmonary artery to the aorta) both close and become obliterated, redirecting blood flow through the lungs and liver as normal adult circulation begins.
Step 5: Conclude that all these changes occur after birth, so the correct answer is that all the listed changes happen in the baby's cardiovascular system after birth.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Changes in Umbilical Vessels After Birth
After birth, the umbilical arteries and vein, which previously carried blood between the fetus and placenta, close and become fibrosed. This process stops placental blood flow and transforms these vessels into ligaments, marking a key step in the newborn's independent circulation.
Recommended video:
5:34
Types of Blood Vessels
Initiation of Pulmonary Circulation
At birth, the lungs expand and pulmonary circulation begins as the baby takes its first breaths. This causes a drop in pulmonary vascular resistance and an increase in blood flow to the lungs, raising pressure in the left side of the heart and enabling oxygenated blood to circulate systemically.
Recommended video:
05:031) Initiation of Translation
Closure of Fetal Shunts: Ductus Venosus and Ductus Arteriosus
The ductus venosus and ductus arteriosus are fetal blood vessels that bypass the liver and lungs, respectively. After birth, these shunts close and become fibrous ligaments, redirecting blood flow through the liver and lungs, which is essential for normal postnatal circulation.
Recommended video:
Guided course
02:12Reproduction
Related Practice