Textbook Question
Give examples of negative and positive feedback in hormonal control of the human menstrual cycle. Why can a high estradiol level be considered a 'readiness' signal from a follicle?
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Ch. 47 - Animal Reproduction and Development
Freeman8th EditionBiological ScienceISBN: 9780138276263
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Table of contents
- Ch. 1 - Biology: The Study of Life13
- Ch. 2 - Water and Carbon: The Chemical Basis of Life14
- Ch.3 - Protein Structure and Function10
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells11
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation11
- Ch. 10 - Photosynthesis12
- Ch. 11 - Cell-Cell Interactions12
- Ch. 12 - The Cell Cycle8
- Ch. 13 - Meiosis12
- Ch. 14 - Mendel and the Gene23
- Ch. 15 - DNA and the Gene: Synthesis and Repair15
- Ch. 16 - How Genes Work16
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria16
- Ch. 19 - Control of Gene Expression in Eukaryotes12
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers15
- Ch. 21 - Genes, Development, and Evolution12
- Ch. 22 - Evolution by Natural Selection16
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea15
- Ch. 27 - Diversification of Eukaryotes16
- Ch. 28 - Green Algae and Land Plants16
- Ch. 29 - Fungi18
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals15
- Ch. 32 - Deuterostome Animals17
- Ch. 33 - Viruses16
- Ch. 34 - Plant Form and Function16
- Ch. 35 - Water and Sugar Transport in Plants16
- Ch. 36 - Plant Nutrition13
- Ch. 37 - Plant Sensory Systems, Signals, and Responses16
- Ch. 38 - Flowering Plant Reproduction and Development16
- Ch. 39 - Animal Form and Function17
- Ch. 40 - Water and Electrolyte Balance in Animals16
- Ch. 41 - Animal Nutrition16
- Ch. 42 - Gas Exchange and Circulation16
- Ch. 43 - Animal Nervous Systems16
- Ch. 44 - Animal Sensory Systems16
- Ch. 45 - Animal Movement11
- Ch. 46 - Chemical Signals in Animals16
- Ch. 47 - Animal Reproduction and Development16
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology15
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology17
- Ch. 54 - Biodiversity and Conservation Ecology18
Chapter 47, Problem 11
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In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action?
Which of the following is the most effective form of contraception?
a. Condom
b. Diaphragm
c. Withdrawal
d. The pill
Verified step by step guidance1
Understand the mechanism of action of oral hormonal contraception: The pill contains synthetic hormones that mimic the natural hormones progesterone and/or estradiol. These hormones work primarily by preventing ovulation, which means they stop the ovaries from releasing eggs.
Explore how the pill prevents ovulation: The synthetic hormones in the pill maintain consistent hormone levels in the body, which tricks the body into thinking it is already pregnant. This prevents the release of the hormones that trigger ovulation.
Consider additional effects of the pill: Besides preventing ovulation, the pill also thickens the cervical mucus, making it difficult for sperm to enter the uterus, and alters the uterine lining, reducing the likelihood of implantation.
Compare the effectiveness of different contraceptive methods: The effectiveness of contraception is often measured by the failure rate, which is the percentage of women who experience an unintended pregnancy within the first year of use. The pill is generally more effective than condoms, diaphragms, and withdrawal when used correctly and consistently.
Identify the most effective form of contraception from the options given: Based on typical use, the pill is considered more effective than the other options listed (condom, diaphragm, withdrawal) due to its lower failure rate when taken as directed.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Mechanism of Action of Oral Hormonal Contraception
Oral hormonal contraception, commonly known as 'the pill,' works primarily by preventing ovulation. It contains synthetic hormones similar to progesterone and estradiol, which inhibit the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland. This suppression prevents the ovaries from releasing eggs, thereby reducing the chance of fertilization and pregnancy.
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Comparison of Contraceptive Effectiveness
The effectiveness of contraceptive methods varies significantly. The pill is considered one of the most effective forms when taken consistently and correctly, with a typical use failure rate of about 7%. In contrast, condoms and diaphragms have higher failure rates due to user error, and withdrawal is the least reliable method. Effectiveness is measured by the percentage of women who experience unintended pregnancies within the first year of use.
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Synthetic Hormones in Contraception
Synthetic hormones used in contraceptive pills mimic natural hormones like progesterone and estradiol. These compounds are designed to maintain stable hormone levels in the body, preventing the hormonal fluctuations that trigger ovulation. By maintaining these levels, synthetic hormones effectively control the menstrual cycle and provide reliable contraception, while also offering benefits like reduced menstrual cramps and regulated cycles.
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Related Practice
Textbook Question
Propose an experiment to test the hypothesis that cells from only one region of a frog blastula form the ectoderm. What results from this experiment would support this hypothesis?
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Textbook Question
The BMI z-score is a relative measure of body mass index (BMI) that takes into account age. Higher values represent heavier individuals for a given height. The table here shows the BMI z-score of pre- and post-pubertal girls at three ages.
Which of the following conclusions can you draw from the data?
a. At a given age, there are more girls with low BMI z-scores than with high BMI z-scores.
b. At a given age, girls with high BMI z-scores are more likely to have begun puberty than girls with low BMI z-scores.
c. Girls 11, 12, and 13 years of age are equally likely to have begun puberty.
d. There is no relationship between BMI z-score and age of beginning puberty.
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Textbook Question
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In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action?
Use your knowledge of the hormonal regulation of reproduction to predict the effect of a daily synthetic progesterone pill on (a) pituitary secretion of LH and FSH, and (b) ovarian secretion of estradiol and progesterone.
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Textbook Question
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In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action?
Scientists confirmed the pill's mechanism of action by measuring plasma hormone levels in women before and after they went on the pill (* means P<0.05, ** means P<0.01, and *** means P<0.001). Do the data shown here support the hypothesis that the pill affects hormonal signaling?
597
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Textbook Question
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In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action?
Use the information in the graph to explain how the pill affects each of the following: (a) maturation of a follicle, (b) thickening of the uterine lining during the follicular phase, (c) probability of ovulation, and (d) volume of menstrual fluid.
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