Chapter 27 Test 6
5. What would happen if someone had a Y chromosome with an SRY gene that was mutated in such a way that no functional SRY protein could be produced? A. The person will generally develop as biologically female. B. The person will generally develop as biologically male. C. The person will be an intersex individual, with some traits of females and some traits of males. D. The person will be an extra-virile "super-male."
A
20. In a typical or "average" cycle, ovulation occurs on day __________. 1 5 14 21 28
Answer: 14
5. The diploid chromosome number in humans is __________. 12 23 24 46
Answer: 46
4. What is a follicle, in the context of the female reproductive system?
Answer: A follicle is an oocyte and the supporting cells that surround it.
2. Which is NOT an adaptation/specialization that applies to sperm cells? A. Acrosome for enzymes to digest material surrounding the oocyte. B. Flagellum for propulsion ("swimming"). C. Lots of glycogen stores for the long journey. D. Lots of mitochondria for ATP production.
Answer: C
3. What are the 3 layers of the uterus, from innermost to outermost?
Answer: Endometrium (innermost), myometrium, perimetrium/serosa (outermost).
38. Which gonadal hormones exert positive feedback on the anterior pituitary that results in a burstlike release of LH?
Answer: Estrogens exert positive feedback on the anterior pituitary that leads to a burstlike release of LH.
19. __________ stimulates the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Inhibin Estrogen Gonadotropin-releasing hormone Progesterone
Answer: Gonadotropin-releasing hormone
10. __________ acts upon the __________ to encourage the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Testosterone; sustentocytes Gonadotropin-releasing hormone (GnRH); anterior pituitary Gonadotropin-releasing hormone (GnRH); sustentocytes Testosterone; anterior pituitary
Answer: Gonadotropin-releasing hormone (GnRH); anterior pituitary
35. What occurs in the luteal phase of the ovarian cycle?
Answer: In the luteal phase, the follicle from which an oocyte has been ovulated develops into a corpus luteum, which then secretes progesterone (and some estrogens).
24. Which hormone stimulates the ruptured ovarian follicle to become the corpus luteum? estrogen FSH LH GnRH
Answer: LH
37. Which hormone prompts ovulation?
Answer: LH prompts ovulation.
6. Which of the following is true about meiosis? Meiosis involves only one cell division event. Meiosis is how most cells in the body divide. Meiosis leads to the production of genetically identical cells. Meiosis produces cells that have a haploid chromosome number.
Answer: Meiosis produces cells that have a haploid chromosome number.
2. What is the final outcome of meiosis?
Answer: Meiosis reduces the chromosomal count from 2n to n and introduces variability.
4. The organ that makes estrogen and progesterone is the __________. vestibular gland vagina ovary pineal gland hypothalamus
Answer: Ovary
8. The surge in LH that occurs during the middle of the ovarian cycle triggers __________. uterine-lining secretion FSH release menstruation activation of primordial follicles ovulation
Answer: Ovulation
12. What is semen?
Answer: Semen is sperm plus the secretions of the male accessory glands.
1.What is the HPG axis?
Answer: The HPG axis is the hormonal interrelationship between the hypothalamus, anterior pituitary, and gonads that regulates the production of gametes and sex hormones.
6. In the context of reproduction, what is the "LH surge"?
Answer: The LH surge is the steep rise in LH concentration in the blood that precedes and causes ovulation.
9. What is the function of the corpora cavernosa?
Answer: The corpora cavernosa allow the penis to become stiff so that it can enter the female vagina to deliver sperm.
2. Recall the basic relationships between the hypothalamus, the anterior pituitary, and thegonads, as covered in Chapter 16. Which reproductionrelated hormones does each structure secrete, and how does each influence the release of other reproductionrelated hormones?
Answer: The hypothalamus secretes GnRH, which stimulates the anterior pituitary to release FSH and LH, which stimulates the gonads to release testosterone (male) or estrogen and progesterone (female), which generally feed back negatively on the hypothalamus and pituitary (aside from the exception of high estrogen levels).
5. What are the subdivisions (phases) of the ovarian cycle? What are the subdivisions (phases) of the uterine cycle?
Answer: The ovarian cycle may be divided into follicular and luteal phases, with ovulation in between. The uterine cycle includes menses, the proliferative phase, and the secretory phase.
23. What are the two main things that the ovaries do?
Answer: The ovaries produce the female gametes and secrete female sex hormones (estrogens and progesterone).
16. Describe the major structural and functional regions of a sperm.
Answer: The sperm head is the compacted DNA-containing nucleus. The acrosome that caps the head is a lysosome-like sac of enzymes. The midpiece contains the energy-producing mitochondria. The tail, a flagellum, is the propulsive structure.
7. The sperm's acrosome __________. contains nutrients has a high density of mitochondria provides motility contains enzymes provides the blood testis barrier
Answer: contains enzymes
18. Within the ovary, progesterone is produced by the __________. secondary follicles tertiary follicles primary follicles corpus luteum corpus albicans
Answer: corpus luteum
20. The functional layer of the endometrium is shed in response to __________. increased progesterone levels increased estrogen levels decreased estrogen levels decreased progesterone levels
Answer: decreased progesterone levels
1. Meiosis results in __________. two identical diploid cells two nonidentical haploid cells four identical diploid cells four nonidentical diploid cells four nonidentical haploid cells
Answer: four nonidentical haploid cells
18. Which of the following are MISMATCHED? follicular phase; development of a secondary oocyte within a dominant follicle ovulation; release of a secondary oocyte ovarian cycle; monthly series of events associated with maturation of an egg luteal phase; characterized by decreased progesterone levels
Answer: luteal phase; characterized by decreased progesterone levels
9. The area of the sperm cell that contains many mitochondria is the __________. midpiece tail acrosome head
Answer: midpiece
23. The muscular layer of the uterine wall is called the __________. endometrium epimetrium myometrium perimetrium
Answer: myometrium
12. In which uterine phase does the functional layer of the endometrium start to rebuild? proliferative secretory preovulatory menstrual ovulation
Answer: proliferative
21. Which of the following is NOT an effect of estrogen? promotes oogenesis promotes the development of secondary sex characteristics in females helps to sustain the density of the skeleton promotes diuresis (water loss)
Answer: promotes diuresis (water loss)
19. Sperm are produced in the __________. epididymis interstitial cells seminal gland seminiferous tubules spermatic cord prostate gland right answer feedback:
Answer: seminiferous tubules
15. In order, list the structures sperm will pass through from the testes to the external urethral orifice. seminiferous tubules, epididymis, vas deferens, ampulla, ejaculatory duct, prostatic urethra, spongy urethra epididymis, ampulla, seminiferous tubules, vas deferens, spongy urethra, prostatic urethra, ejaculatory duct epididymis, seminiferous tubules, ampulla, vas deferens, prostatic urethra, ejaculatory duct, spongy urethra ejaculatory duct, epididymis, seminiferous tubules, vas deferens, spongy urethra, prostatic urethra, ampulla
Answer: seminiferous tubules, epididymis, vas deferens, ampulla, ejaculatory duct, prostatic urethra, spongy urethra
9. The usual site of fertilization is the __________. vagina uterine tube uterus vulva ovary
Answer: uterine tube
6. The "rhythm method" is a contraception strategy in which a couple does not have sex around the time of ovulation. What is a limitation of this strategy? A. The day of ovulation is completely unpredictable. Sperm can hang around a while after being introduced into the female. This may simply lead to asexual reproduction instead. The ovaries will simply postpone ovulation until sperm are present in the body.
B
4. Which uterine phase corresponds to the luteal phase of the ovarian cycle? A. menses B. proliferative C. secretory D. all of the above
C
3. Which hormone is mostly low in the follicular phase and then rises high for much of the luteal phase? A. estrogen FSH LH progesterone
D
7. Can vasectomized males still ejaculate? A. No, because they can't have erections any more. B. No, because there is no fluid to ejaculate. C. Yes, but what comes out is urine rather than semen. D. Yes -- what comes out is semen that doesn't contain any sperm.
D
What ovarian phase is happening in the first 13 days of the cycle?
Folicular, when the follicle is swelling.
What occurs during the first 5 days of the uterine cycle
Menses. Much of the endometrium is shed.
What ovarian phase is occurring on the 14th day of the cycle
Ovulation, when the oocyte is ejected from the follicle
What occurs during the 5-14th day of the uterine phase?
Proliferative phase. Endometrium is rebuilt
Q1. How many days are shown for this ovarian cycle? Can this cycle length vary?
Q1. 28 days. Yes, it can vary!
Q1. Why does the blood get trapped in the penis? (2 reasons)
Q1. Arteriole valves (it's unusual for arterioles to have these) prevent backflow; the main vein gets compressed closed.
Q1: How are vasectomies done?
Q1. How done: what part of pathway is disrupted by a VASectomy? Vas deferens (ductus deferens). Just cut it! Sperm are still made, but leak out - don't make it to the ejaculatory duct.
Q1. Evaluate the correctness of the following statement: "Toward the end of the cycle, the decline in estrogen and progesterone levels causes the corpus luteum to shrivel up."
Q1. It's true that estrogen and progesterone levels decline at the end of the cycle, and that the corpus luteum decays. However, the statement has the causality backwards; the decay of the corpus luteum causes it (the corpus luteum) to produce less estrogen and progesterone.
Q1. What is the key GENE on the Y chromosome?
Q1. SRY (sex-determining region of the Y chromosome) = TDF (testis-determining factor).
What is the purpose of meiosis, in terms of the number of chromosomes?
Q1. The purpose of meiosis is to shuffle genetic information and cut the cellular chromosome number in half, from 46 chromosomes to 23 chromosomes. *** This answer was not provided in Dr. C's answer key and is my best educated answer.
Which hormone is the best indication that a woman is ovulating?
Q1. luteinizing hormone (LH).
Q10. The anterior pituitary secretes 2 gonadotropins (hormones that target the gonads). Name them (both full names and abbreviations).
Q10. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
Q11. Using the diagram at right, show the location of the anterior pituitary and ovaries. How do gonadotropic hormones move from the anterior pituitary to the ovaries?
Q11. The anterior pituitary is the structure in the head; the ovaries are the lowest pair of structures shown (toward bottom of abdominopelvic cavity).
Q12. Plasma gonadotropin levels peak on day 13. What ovarian event immediately follows the LH surge?
Q12. Ovulation (release of oocyte from follicle).
Q13. What do you think is the main function of FSH? Of LH? (Consider both their full names and the relationships illustrated in Model 3.)
Q13. FSH stimulates growth and development of the dominant follicle. LH stimulates formation of the corpus luteum (hence its name) and stimulates ovulation.
Q19. During the luteal phase, is there a relationship between the levels of progesterone and the thickness of the endometrium?
Q19. There is a direct correlation - higher progesterone promotes further thickening of the endometrium, and lower progesterone goes along with shedding of the endometrium.
How does estrogen (and progesterone) work as a birth control pill?
Q2. Low-to-moderate levels of estrogen and progesterone feed back NEGATIVELY on the hypothalamus and anterior pituitary. So if these hormones are always somewhat elevated, but not TOO high, LH will be kept in check and will never surge, and ovulation will never occur!
Q2. What changes can be seen in the follicle between days 0 and 12?
Q2. The follicle gets bigger (follicular cells divide) and fills with fluid.
Q2. What does this gene do?
Q2. This gene, by turning on other genes, causes the gonads to develop into testes rather than ovaries. Testes start making testosterone, which guides further changes. People are "female by default"; in the absence of SRY, ovaries will develop.
Q2. Why would it be counterproductive for the corpus spongiosum to become as engorged as the corpora cavernosa?
Q2. Uretha (amidst corpus spongiosum) needs to stay open so sperm can leave!
Q2. Are vasectomies reversible?
Q2. Yes, vasectomies are often reversible. They don't prevent the male from making sperm, but the cut to the vas deferens has to be repaired so that the sperm can get to the urethra and out.
Q2. In the absence of an actual pregnancy, how can a clinic tell whether a vasectomy was successful?
Q2. Yes, vasectomies are often reversible. They don't prevent the male from making sperm, but the cut to the vas deferens has to be repaired so that the sperm can get to the urethra and out. Semen samples can be collected for "semenalysis" to assess the quantity and quality (e.g., swimming ability) of the sperm.
Q20. Based on your answer to the previous question, what is the main function of progesterone?
Q20. Progesterone promotes preparation of the uterus for possible implantation of the offspring.
Q21. Why is it important for the endometrium to increase in thickness and vascularity during the menstrual cycle?
Q21. To be ready to support the new offspring if it implants in the endometrium.
Q3. How does Viagra work?
Q3. It inhibits cGMP breakdown inside the smooth muscle cells in the arteriole walls, causing these muscle cells to relax, increasing blood flow.
Q3. What multi-step cell division process produces gametes? Why do human gametes have only 23 chromosomes (as opposed to 46)?
Q3. Meiosis helps make gametes. Gametes have only 23 chromosomes because, starting with 46 chromosomes, meiosis includes only 1 round of DNA replication but 2 rounds of cell division. Alternative answer: each gamete should only have 23 chromosomes so that the fusion of oocyte and sperm nuclei results in the 46 chromosomes needed to make a baby.
Q4. After ovulation, the follicular cells become a structure called the corpus luteum. What is ovulation? What happens to the oocyte?
Q4. Ovulation is the ejection of the oocyte out of the follicle. Oocyte goes into the fallopian tube.
Q5. The corpus luteum secretes estrogen and progesterone. Examine the size of the corpus luteum from days 15 to 28 in Model 1 and predict how changes in the size of the corpus luteum affect its endocrine function.
Q5. Release of estrogen and progesterone correlate with the size of the corpus luteum - more is secreted as the corpus luteum grows, then less is secreted as it shrivels up.
Q5. What are the two phases of the ovarian cycle? How do they normally correspond to the phases shown in Q4 above?
Q5. The two phases of the ovarian cycle are the follicular phase (corresponding to menses and the proliferative phase of the uterine cycle - days 1 to 14 of a typical 28-day cycle) and the luteal phase (corresponding to the secretory phase of the uterine cycle - days 15 to 28 of a typical 28-day cycle).
Q6. Name the two sex steroid hormones (ovaries)
Q6. Estrogen and progesterone.
Q6. Urine tests can help women tell when they are ovulating. Which hormone is measured in these tests? What is the source of this hormone?
Q6. Ovulation test: luteinizing hormone (LH) from anterior pituitary.
Q7. For each of these hormones, name the ovarian phase during which it reaches its peak.
Q7. Estrogen peaks during the follicular phase; progesterone peaks during the luteal phase.
Q7. How is the hypothalamic-pituitary-gonadal axis similar to and different from the usual hypothalamic-pituitary axis (as discussed in Chapter 16: The Endocrine System)?
Q7. The general pattern that holds true for the thyroid and the adrenal cortex is that hormones from the hypothalamus stimulate the release of hormones by the anterior pituitary, which stimulate the release of other hormones by the target glands (thyroid or adrenal cortex), which then feed back negatively on the hypothalamus and anterior pituitary. Most of this applies to the reproductive system as well; GnRH from the hypothalamus stimulates FSH and LH release from the anterior pituitary, which then stimulate production of sex hormones by the gonads, which generally feed back negatively. However, estrogen produced by the ovaries, if present at high enough levels, can feed back POSITIVELY on the hypothalamus and anterior pituitary.
Q8. Why do you think plasma levels of both sex steroid hormones decrease near the end of the cycle?
Q8. Because of the shrinkage of the corpus luteum.
Q8. A sperm can be divided into 3 anatomical parts. What are they? How does the structure of each reflect its function?
Q8. Head: contains acrosome (with enzymes to get through corona radiata and zona pellucida to oocyte) and DNA (to add to the oocyte DNA). Midpiece: contains lots of mitochondria to provide ATP for the long "swim." Tail: a flagellum to allow the sperm to move toward the oocyte.
Q9. In a normal cycle of a non-pregnant woman, does each of the following occur during the follicular phase, the luteal phase, both, or neither? (A) Estrogen levels rise while progesterone levels stay relatively low, (B) the corpus luteum grows in size, (C) both estrogen and progesterone levels decline toward the end of this phase.
Q9. (A) Estrogen levels rise while progesterone levels stay relatively low - FOLLICULAR. (B) The corpus luteum grows in size - LUTEAL. (C) Both estrogen and progesterone levels decline toward the end of this phase - LUTEAL.
Q9. Do estrogen levels peak before, at, or after ovulation?
Q9. Estrogen levels peak very shortly before ovulation.
What occurs during th 14-28th day of the uterine phase
Secretory phase. Endometrium becomes even thicker and more richly vascularized.
What ovarian phase is occurring during the 15th to the 28th day of the cycle?
The luteal phase, when the follicle becomes the corpus luteum and grows, then starts shriveling up.
If some guy has 100,000 mL sperm per mL of Semen, is he infertile?
Yes, he is basically shooting blanks