bio 11 reproduction
A woman with type B- blood type experiences a miscarriage during the 10th week of her first pregnancy. The blood type of the father is unknown at the time. Should fetal hemolytic disease be of sufficient concern to administer Rhogam (anti-Rh antibodies)? A. Yes; without knowing the blood type of the father, the fetus may have been Rh+ which could impact future pregnancies. B. Yes; Rhogam should always be administered after a miscarriage, no matter what the mother's blood type. C. No; the risks of administering Rhogam are typically outweighed by the benefits to the mother. D. No; Rhogam should be given to women with Rh+ positive blood types to prevent hemolysis in Rh- fetuses.
A A woman with type B- blood type experiences a miscarriage during the 10th week of her first pregnancy. Yes, fetal hemolytic disease be of sufficient concern to administer Rhogam (anti-Rh antibodies); without knowing the blood type of the father, the fetus may have been Rh+ which could impact future pregnancies. Rhogam counteracts antibodies that the body of a mother with Rh- blood may form when she is exposed to Rh+ blood from a baby during delivery or during the removal of the products of conception at the time of a miscarriage. Hemolysis during the current pregnancy is less of a concern; rather the drug is given to prevent hemolysis in future pregnancies when the antibodies would already be well established. The reasons to administer the drug are not related to how the pregnancy ended and are related to the fetus or baby rather than the mother.
Why is light-headedness and occasional dizziness a common symptom for women in their second trimester of pregnancy? A. While the maternal circulatory system has expanded to accommodate the needs of the growing fetus, the production of blood itself needs to fill in the new capacity. B. Maternal myoglobin production has increased and stores more oxygen in the mother's muscles to prepare for labor. C. The increased affinity for oxygen demonstrated by fetal hemoglobin removes too much oxygen from the maternal blood supply. D. Pressure from the expanding uterus makes breathing difficult, thus limiting the amount of oxygen exchange with the blood supply.
A. Light-headedness and occasional dizziness is a common symptom for women in their second trimester of pregnancy because while the maternal circulatory system has expanded to accommodate the needs of the growing fetus, the production of blood itself needs to fill in the new capacity. During the second trimester, the capacity to supply blood to the fetus is expanding, but the maternal hematopoietic tissues take longer to produce enough blood to fill what the new vasculature can hold. This can lead to dizziness until that gap in capacity closes. Obstruction of breathing by the uterus typically does not take place until the third trimester and though it can impinge on lung capacity, it does not interfere with circulatory exchange. Though fetal hemoglobin has a higher affinity for oxygen than the maternal hemoglobin, this is not so extensive as to actively deprive the mother of oxygen. By that same token, the muscles are not storing so much oxygen as to deprive standard circulation.
A mother just gave birth to a child and directly experienced the effects of oxytocin. What are the possible effects of oxytocin? I. A decrease in oxytocin causes labor to begin. II. Once labor begins, the posterior pituitary increases secretion of oxytocin which causes increased uterine contractions. III. Oxytocin facilitates milk let-down for breastfeeding. A. II and III only B. I, II, and III C. III only D. I and II only
A. A mother just gave birth to a child and directly experienced the effects of oxytocin. The possible effects of oxytocin are II and III only. I. A decrease in oxytocin causes labor to begin. II. Once labor begins, the posterior pituitary increases secretion of oxytocin which causes increased uterine contractions. III. Oxytocin facilitates milk let-down for breastfeeding. Item I is false: It is a drop in progesterone, not oxytocin, that causes labor to begin (choices with Item I can be eliminated). Since both remaining answer choices include Item III, Item III must be true and you can focus on Item II. Item II is true: Once labor begins, the secretion of oxytocin by the posterior pituitary is increased via a positive feedback mechanism, and this functions to increase the intensity of uterine contractions (choice "III only" can be eliminated). Note that Item III is in fact true: After parturition, oxytocin release (stimulated by suckling) facilitates milk let-down.
The myometrium is the muscular layer of the uterus. Each of the following is true regarding the myometrium EXCEPT: A. it is more superficial (closer to the lumen) than the endometrium. B. it is composed of muscle cells that have no sarcomeres. C. it contracts during labor in response to oxytocin. D. it enlarges during pregnancy.
A. The myometrium is made of smooth muscle that enlarges during pregnancy (choice D is true and can be eliminated) and contracts during labor in response to oxytocin (choice C is true and can be eliminated). Smooth muscle lacks the regular arrangement of actin and myosin found in skeletal and cardiac muscle; that arrangement is referred to as a sarcomere, so the myometrial cells lack sarcomeres (choice B is true and can be eliminated). The endometrium is closest to the lumen of the uterus. The myometrium is found around the endometrium, further from the lumen (choice A is not true and is the correct answer choice). Note that the term "superficial" means "closer to the surface of the body." For open body cavities such as the uterus, since the lumen of the cavity is continuous with the surface of the body, it is considered the most superficial region of that cavity.
It can be inferred from the passage that LH and FSH levels during pregnancy: A. are lower than in nonpregnant females. B. increase and decrease in a cyclical manner. C. remain elevated. D. are similar to levels found during the menstrual cycle.
A. The passage describes the endocrine role of the placenta in secreting estrogen and progesterone during pregnancy, and states that the levels of these hormones are elevated. Since estrogen and progesterone have negative feedback effects on the pituitary hormones (FSH and LH) it is safe to assume that the levels of the pituitary hormones would be low during pregnancy. And since estrogen and progesterone are elevated relative to a non-pregnant female, it is safe to assume that FSH and LH would be lower than in a non-pregnant female (choice A is correct and choice C is wrong). The cyclical increase and decrease of FSH and LH are to be expected during non-pregnant times (i.e., during the normal menstrual cycle), however they remain consistently low during pregnancy due to the effects describe above (choices B and D are wrong).
oogonium -1-> primary oocyte -2-> secondary oocyte -3-> fertilized egg -4-> zygote Anaphase I of meiosis occurs in which of the phases of oocyte development shown above? A. 1 B. 2 C. 3 D. 4
Anaphase I of meiosis occurs in phase 2 of oocyte development shown above. During meiosis, there are two rounds of cell division: meiosis I and meiosis II. During embryonic development of females, oogenesis proceeds up to the formation of primary oocytes, which are arrested in meiotic prophase I. They will remain arrested at this stage up until the time that they prepare for ovulation and complete meiosis I, including going through anaphase I, to form secondary oocytes which are ovulated. Stage 2, the progression from primary to secondary oocytes, includes anaphase I.
The primary follicle includes each of the following EXCEPT: A. the zona pellucida. B. the second polar body. C. thecal cells. D. granulosa cells.
B The primary follicle does NOT include the second polar body. The primary follicle includes a primary oocyte and, moving outward from the egg surface, a zona pellucida, granulosa cells, and thecal cells (making these all incorrect answer choices). The second polar body is formed after completion of the second meiotic division, only after fertilization and much later than when the primary follicle is present (making this the correct answer).
At birth, females possess the total number of their potential ova. In oogenesis, meiotic division is arrested for a long period at which stage? A. Secondary oocyte B. Primary oocyte C. Oogonium D. Ovum
B. At birth, females possess the total number of their potential ova. In oogenesis, meiotic division is arrested for a long period at the primary oocyte stage. Primary oocytes are arrested in meiotic prophase I in the ovaries from birth until they are stimulated to ovulate sometime during sexual maturity.
Why are women who wish to breastfeed counseled against taking birth control pills that combine estrogen and progestins as the means to block ovulation? A. High levels of estrogen and progesterone inhibit follicle stimulating hormone as well as ovulation. B. High levels of estrogen and progesterone inhibit prolactin as well as ovulation. C. High levels of estrogen and progesterone inhibit relaxin as well as ovulation. D. High levels of estrogen and progesterone inhibit oxytocin as well as ovulation.
B. Women who wish to breastfeed counseled against taking birth control pills that combine estrogen and progestins as the means to block ovulation because high levels of estrogen and progesterone inhibit prolactin, the hormone responsible for milk production at the mammary glands. This is beneficial during pregnancy when there may not be a baby to feed, but needs to not occur during times of active lactation. These hormones do not inhibit oxytocin and while they do inhibit follicle stimulating hormone, FSH is not involved in lactation. Similarly, relaxin, the hormone of pregnancy that loosens the joints, is not inhibited by these hormones.
A physician is treating four different women, each of whom is taking oral birth control pills (BCP). BCPs generally function to inhibit gonadotropin release and therefore inhibit ovulation. Which one of the following patients should be LEAST worried that the BCP will be ineffective? A. A patient taking an anti-depressant drug, which early studies have shown might alter hormone levels B. A patient who is taking a weight-loss prescription, which elevates her liver metabolism levels significantly C. A patient who is taking a GnRH antagonist, which competes with GnRH for the GnRH receptor D. A patient with irritable bowel syndrome, who has been suffering from severe diarrhea frequently in the last month
C. A physician is treating four different women, each of whom is taking oral birth control pills (BCP). BCPs generally function to inhibit gonadotropin release and therefore inhibit ovulation. A patient who is taking a GnRH antagonist, which competes with GnRH for the GnRH receptor should be LEAST worried that the BCP will be ineffective. It is possible that a patient with elevated liver metabolism would degrade the hormones in the BCP faster than usual, and hormone levels could be lower than they should be (this patient should be worried and "A patient who is taking a weight-loss prescription, which elevates her liver metabolism levels significantly" can be eliminated). It is possible that a patient with severe diarrhea, because of increased motility in the GI tract, is not absorbing the hormones in the pill properly (this patient should also be worried and "A patient with irritable bowel syndrome, who has been suffering from severe diarrhea frequently in the last month" can be eliminated). If a certain anti-depressant drug changes hormone levels in the body, it is possible that it might interact with or affect the hormones in the BCP (this patient should be worried and "A patient taking an anti-depressant drug, which early studies have shown might alter hormone levels" can be eliminated). However, if a GnRH antagonist competes for the GnRH receptors, this would reduce the effects of GnRH, leading to a decrease in the release of the gonadotropins, which mimics the effect of the BCP. This patient has little to worry about ("A patient who is taking a GnRH antagonist, which competes with GnRH for the GnRH receptor" is correct). In fact, in certain cases, GnRH antagonists can be used to inhibit ovulation.
Which of the following is NOT under control of the sympathetic nervous system in a male? A. Emission of sperm and semen through the urethra B. Ejaculation of sperm and semen C. Dilation of arteries in the erectile tissue D. Resolution, or constriction of arteries in the erectile tissue
C. Dilation of arteries in the erectile tissue is NOT under control of the sympathetic nervous system in a male. Only the first phase of the male sexual act, arousal, is under control of the parasympathetic nervous system. This includes dilation of arteries in the erectile tissue ("Dilation of arteries in the erectile tissue" is not controlled by the sympathetic system and is the correct answer choice). The orgasm (emission and ejaculation) and resolution (constriction of erectile arteries) phases of the male sexual act are under sympathetic control ("Emission of sperm and semen through the urethra", "Ejaculation of sperm and semen" and "Resolution, or constriction of arteries in the erectile tissue" are under control of the sympathetic nervous system and can be eliminated).
During the menstrual cycle, the corpus luteum degrades, but if a fertilized ovum implants in the uterus, the corpus luteum persists. Which of the following hormones supports the corpus luteum during pregnancy? A. Progesterone B. Lutenizing hormone C. Human chorionic gonadotropin D. Estrogen
C. During the menstrual cycle, the corpus luteum degrades, but if a fertilized ovum implants in the uterus, the corpus luteum persists. Human chorionic gonadotropin supports the corpus luteum during pregnancy. Human chorionic gonadotropin (hCG) is secreted by the trophoblast, beginning at implantation. hCG plays a role similar to that of lutenizing hormone (LH) in maintaining the corpus luteum. In the presence of hCG, the corpus luteum continues to secrete estrogen and progesterone to maintain the uterine lining so that the pregnancy is not lost. The trophoblast ultimately develops into the placenta (by about the 3rd month of gestation), which takes over the endocrine role of the corpus luteum.
Which of the following is a true statement? A. Inhibin, released by interstitial cells, inhibits FSH release. B. The posterior pituitary secretes LH, which acts on interstitial cells. C. Interstitial cells secrete testosterone, which inhibits release of LH and FSH. D. The anterior pituitary secretes FSH, which acts on interstitial cells.
C. The following is a true statement: Interstitial cells secrete testosterone, which inhibits release of LH and FSH. Leydig cells secrete testosterone, which causes development of male secondary sexual characteristics in males. Testosterone feeds back to the anterior pituitary (and the hypothalamus) to inhibit release of FSH and LH. The anterior pituitary does secrete FSH, however it stimulates Sertoli cells (also known as sustentacular cells), not Leydig cells ("The anterior pituitary secretes FSH, which acts on interstitial cells" is wrong). LH is also secreted by the anterior pituitary (not the posterior, "The posterior pituitary secretes LH, which acts on interstitial cells" is wrong) and stimulates Leydig cells (also known as interstitial cells) to secrete testosterone ("The posterior pituitary secretes LH, which acts on interstitial cells" is wrong). Sertoli cells (not Leydig cells) secrete inhibin, which decreases FSH secretion from the anterior pituitary ("Inhibin, released by interstitial cells, inhibits FSH release" is wrong).
The luteal phase of menstruation is consistently 14 days in length, yet normal menstrual cycles can vary anywhere from 21 to 35 days. During which phase of the cycle does this variation occur? A. Secretory phase B. Ovulatory phase C. Follicular phase D. Menstrual phase
C. The luteal phase of menstruation is consistently 14 days in length, yet normal menstrual cycles can vary anywhere from 21 to 35 days. This variation occurs during the follicular phase of the cycle. The phases of the ovary drive activity in the uterus during the menstrual cycle, so variability in the length of the cycle lies with the ovarian phases. The ovulatory phase really refers to the length of time during which the egg is viable; though this can vary from 24-48 hours, this is not enough to account for days' worth of differences in the length of menstrual cycles. However, the follicular phase can be variable enough to cause normal menstrual cycles to have a great deal of variation. The menstrual and secretory phases are uterine rather than ovarian and therefore would not cause this variation.
The structure which secretes progesterone during the luteal phase of the ovarian cycle is called the: A. ovarian medulla. B. follicle. C. corpus luteum. D. corona radiata.
C. The structure which secretes progesterone during the luteal phase of the ovarian cycle is called the corpus luteum. Follicle is incorrect since the follicle is present during the follicular phase, not the luteal phase. The corona radiata is the group of cells surrounding the oocyte after ovulation, and the ovarian medulla is mostly connective tissue and blood vessels and does not secrete anything, so both of these may be eliminated. The corpus luteum is the remnant of the follicle after ovulation has occurred. It is an endocrine structure that secretes progesterone (and which the luteal phase is named for).
ne of the first hormones produced by a developing embryo is hCG, human chorionic gonadotropin. The function of hCG is to prolong the life of the corpus luteum, ensuring that the endometrium is maintained until full development of the placenta by 3 months of gestation. hCG is most like which of the following hormones? A. Estrogen B. Progesterone C. LH D. FSH
C. hCG is most like LH. The LH (luteinizing hormone) surge in the middle of the menstrual cycle triggers both ovulation and the conversion of the follicular remnants into the corpus luteum, which then secretes progesterone and estrogen. However, levels of LH rapidly fall, and in the absence of LH the corpus luteum only survives for about two weeks. At the end of that time period, the corpus luteum degenerates, the levels of progesterone and estrogen fall, and menstruation occurs. In order to maintain the endometrium in the case of pregnancy, levels of progesterone and estrogen must remain elevated, and in order keep the levels elevated, the corpus luteum must be maintained. hCG takes on the role of LH in this regard. FSH does not affect formation or maintenance of the corpus luteum. Further it does not make logical sense for hCG to be like progesterone or estrogen; if this was the case, there would be no need to maintain the corpus luteum to secrete those hormones.
When does a secondary oocyte become an ootid? A. During the luteal phase of the menstrual cycle, after ovulation but before fertilization. B. In utero, where the secondary oocyte will remain frozen in metaphase II until puberty. C. After fertilization, but before the egg and sperm nuclear membranes fuse. D. During the follicular phase of the menstrual cycle, just prior to ovulation.
C. A secondary oocyte become an ootid after fertilization, but before the egg and sperm nuclear membranes fuse. Each month during a woman's reproductive years, a few primary oocytes complete meiosis I to become secondary oocytes. These secondary oocytes never progress beyond metaphase II unless they are fertilized, at which time they complete meiosis II to become ootids, then develop into mature ova in a matter of minutes.
During pregnancy, the levels of progesterone and estrogen: A. are constant and lower than in a non-pregnant female. B. increase and decrease in a cyclical manner. C. are elevated significantly above levels in a nonpregnant female. D. are similar to levels found during the menstrual cycle.
C. During pregnancy, the levels of estrogen and progesterone must be constant (choices B and D are wrong) and fairly elevated (choice A is wrong) to maintain/increase the uterine lining.
Which of the following is/are functions of the placenta? To maintain the corpus luteum by secreting hCG Providing a site for blastocyst implantation To secrete estrogen during pregnancy A. I only B. III only C. I and III only D. II and III only
C. Item I is true: the trophoblast is the early precursor (months 0-3) of the placenta. It secretes hCG which acts in a manner similar to LH to maintain the corpus luteum (choices B and D can be eliminated). Since neither of the remaining choices includes Item II, it must be false: the blastocyst implants in the uterine lining (endometrium). Statement III is true: once the placenta is mature (months 4-9) it secretes estrogen and progesterone (choice A can be eliminated and choice C is correct).
During the first trimester, a pregnant woman develops an autoimmune disorder in which antibodies to hCG are formed. The result is: Continued pregnancy Termination of pregnancy Regression of the corpus luteum A. I only B. II only C. II and III only D. I and III only
C. The purpose of hCG is to act as a substitute for LH. The corpus luteum is formed in the presence of LH, but as the LH levels fall after ovulation, the corpus luteum begins to deteriorate. The corpus luteum is responsible for secreting progesterone, which helps to maintain the uterine lining, in case that particular ovulation results in a pregnancy. As the corpus luteum deteriorates, the levels of progesterone fall, and when they fall low enough, menstruation begins. The role of hCG, then, is to prolong the life of the corpus luteum (much like LH would if it were still present). If the corpus luteum does not deteriorate, progesterone levels stay high, and menstruation does not occur. An autoimmune disorder in which anti-hCG antibodies were formed would result in the destruction of hCG, the deterioration of the corpus luteum (Statement III is true), a fall in progesterone levels, and the onset of menstruation (termination of the pregnancy, Statement II is true and Statement I is false).
Which of the following cells is NOT haploid? A. Secondary spermatocyte B. Spermatozoon C. Spermatid D. Primary spermatocyte
D. A primary spermatocyte is NOT haploid. The spermatozoon, spermatid, and the secondary spermatocyte all occur in spermatogenesis after the first meiotic division; thus they have all had their chromosome numbers reduced and are haploid (since they are haploid, they can be eliminated as answer choices). The primary spermatocyte gets activated from the spermatogonium and is ready to enter meiosis I, thus it has not undergone any divisions in meiosis and is still diploid (primary spermatocyte is not haploid and the correct answer choice).
Human chorionic gonadotropin (hCG) is secreted from which structure to help maintain pregnancy? A. Inner cell mass B. Morula C. Zygote D. Trophoblast
D. Human chorionic gonadotropin (hCG) is secreted from the trophoblast to help maintain pregnancy. Human chorionic gonadotropin (hCG) is secreted from the trophoblast (which ultimately becomes the placenta) during early development to keep the corpus luteum from degenerating. This keeps progesterone high in order to maintain the uterine lining. The inner cell mass ultimately becomes the embryo and does not secrete hCG, the zygote is the initial cell formed when the sperm and egg fuse, and the morula is a solid ball of cells formed after many cell divisions of the zygote, making each of these incorrect answer choices.
Follicular development is stimulated by a rise in FSH and normally leads to a subsequent rise in estrogen. The failure of a developing follicle to produce estrogen would cause which of the following events? I. Lack of endometrial development II. Failure to ovulate III. Premature menstruation A. II and III B. I only C. I, II, and III D. I and II
D. I. Lack of endometrial development II. Failure to ovulate III. Premature menstruation The failure of a developing follicle to produce estrogen would cause a lack of endometrial development and failure to ovulate. Rising estrogen levels during the follicular phase of the menstrual cycle cause the endometrial lining of the uterus to thicken; a lack of estrogen would prevent the development of the endometrium (Item I is true). Also, the rising levels of estrogen have a positive feedback effect on LH, causing the LH surge that triggers ovulation. Without estrogen there would be no surge and no ovulation (Item II is true). However, menstruation would most likely be delayed; it is the sudden drop in estrogen and progesterone at the end of the cycle that lead to endometrial degradation and menstruation. If estrogen isn't present and the endometrium fails to develop, there would likely be a complete cessation of menstruation (amenorrhea; Item III is false).
Removal of both ovaries during the 2nd trimester of pregnancy would lead to which of the following? A. The mother could become pregnant in the future. B. The pregnancy would be terminated. C. The source of human chorionic gonadotropin would be removed. D. The mother would never menstruate again.
D. Removal of both ovaries would result in the woman being unable to produce estrogen and progesterone during the normal menstrual cycle. Since these hormones control the growth of the uterine endometrium, the absence of the hormones would lead to a lack of uterine function. In other words, the endometrium would never be built up and never be shed off; menstruation would cease. Note that since during pregnancy estrogen and progesterone are produced by the placenta, the current pregnancy would be unaffected (choice B is wrong). In addition to the cessation of menstruation, the woman would be unable to become pregnant in the future, since all of the primary oocytes are found in the ovaries (choice A is wrong). The source of hCG is the trophoblast of the implanted embryo; removal of the ovaries would not affect this (choice C is wrong).