Textbook Question
The structure(s) that allow(s) active and passive exchange between the fetal and maternal bloodstreams is/are the
(a) Yolk stalk
(b) Chorionic villi
(c) Umbilical veins
(d) Umbilical arteries
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Ch. 29 Development and Inheritance
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011
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Table of contents
- Ch. 1 An Introduction to Anatomy and Physiology25
- Ch. 2 The Chemical Level of Organization34
- Ch. 3 The Cellular Level of Organization29
- Ch. 4 The Tissue Level of Organization24
- Ch. 5 The Integumentary System17
- Ch. 6 Bones and Bone Structure33
- Ch. 7 The Axial Skeleton11
- Ch. 8 The Appendicular Skeleton17
- Ch. 9 Joints13
- Ch. 10 Muscle Tissue12
- Ch. 11 The Muscular System28
- Ch. 12 Nervous Tissue18
- Ch. 13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes22
- Ch. 14 The Brain and Cranial Nerves20
- Ch. 15 Sensory Pathways and the Somatic Nervous System17
- Ch. 16 The Autonomic Nervous System and Higher-Order Functions30
- Ch. 17 The Special Senses15
- Ch. 18 The Endocrine System21
- Ch. 19 Blood31
- Ch. 20 The Heart31
- Ch. 21 Blood Vessels and Circulation26
- Ch. 22 The Lymphatic System and Immunity25
- Ch. 23 The Respiratory System4
- Ch. 24 The Digestive System18
- Ch. 26 The Urinary System31
- Ch. 27 Fluids & Electrolytes30
- Ch. 28 The Reproductive System12
- Ch. 29 Development and Inheritance17
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011Not the one you use?Change textbook
Chapter 28, Problem 12
List the factors involved in initiating labor contractions.
Verified step by step guidance1
Understand that labor contractions are initiated by a complex interplay of hormonal and physiological factors that prepare the uterus for childbirth.
Identify the key hormones involved, such as increased levels of oxytocin, which stimulates uterine muscle contractions, and prostaglandins, which help soften and dilate the cervix.
Recognize the role of fetal signals, including the release of cortisol from the fetal adrenal glands, which influences the production of estrogen and prostaglandins in the mother.
Consider the changes in the balance of progesterone and estrogen; a decrease in progesterone's relaxing effect on the uterus and an increase in estrogen promote contractility.
Acknowledge mechanical factors such as uterine stretching and pressure from the growing fetus, which can stimulate the release of oxytocin and enhance contractions.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hormonal Regulation of Labor
Labor contractions are primarily initiated by hormonal changes, especially the increase in oxytocin and prostaglandins. Oxytocin stimulates uterine muscle contractions, while prostaglandins help soften and dilate the cervix, facilitating labor progression.
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13:06
Review of Major Hormones
Mechanical Stretching of the Uterus
As the fetus grows, the uterus stretches, which triggers mechanoreceptors that signal the brain to release hormones like oxytocin. This mechanical stretching is a key factor in starting the rhythmic contractions necessary for labor.
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3:44The Uterus
Fetal Signals and Maturation
The fetus plays an active role by releasing signals such as cortisol that promote lung maturation and stimulate the placenta to produce labor-inducing hormones. These fetal signals help coordinate the timing of labor initiation.
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Related Practice
Textbook Question
A normally pigmented woman whose father was an albino marries a normally pigmented man whose mother was an albino. What is the probability that they would have an albino child?
(a) 50 percent
(b) 25 percent
(c) 12.5 percent
(d) 6.25 percent
(e) 100 percent
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Textbook Question
What hormonal events are responsible for puberty? Which life stage does puberty initiate?
Textbook Question
Problems involving the formation of the chorion would affect
(a) The embryo’s ability to produce blood cells
(b) The formation of limbs
(c) The embryo’s ability to derive nutrition from the mother
(d) Lung formation
(e) The urinary system
Textbook Question
What are the four extra-embryonic membranes?
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Textbook Question
If an allele must be present on both the maternal and paternal chromosomes to affect the phenotype, the allele is said to be
(a) Dominant
(b) Recessive
(c) Complementary
(d) Heterozygous
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