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Appendix F

urinating. An enlarged prostate glandcompresses the prostatic urethra, slow-ing the emptying of the urinary bladderand enhancing the urgency to urinate.Dr. Procter conducted a digital exam bypalpating the men’s prostate glands throughtheir rectums. The patient with the enlargedbut smooth prostate is likely to have benignprostatic hypertrophy and low blood levelsof PSA. Benign prostatic hypertrophy isgeneral enlargement of the prostate with-out specific tumors. The patient with theenlarged but asymmetrical prostate glandis more likely to have elevated blood levelsof PSA and prostate cancer. Lack of sym-metry and a rough surface can be caused bytumors within the prostate gland.10. The correct answer is d . If a testis failsto descend into the scrotal sac, the higherbody temperature causes the spermatogoniato degenerate. Consequently, that testisproduces no sperm cells. Sustentacular cellsremain in the seminiferous tubules, andinterstitial cells remain in the testis. Bothtestosterone secretion by the interstitialcells and LH secretion from the anteriorpituitary gland remain normal.11. The correct answer is d . Decreased bloodflow to the anterior pituitary gland wouldresult in decreased LH secretion, notincreased LH secretion. The decreasedsecretion of LH from the anterior pituitarycauses a decrease in the blood level oftestosterone. Because it takes approxi-mately 74 days to produce a sperm cell, thesperm count is likely to remain normal dur-ing the week when the blood LH and FSHlevels are reduced.

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Chapter 29

1. Triploidy can occur as a result of polysper-my, the fertilization of one oocyte with twosperm cells. Polyspermy is usually preventedby the fast and slow blocks to polyspermy,both of which depend on the depolarizationof the oocyte membrane. If this depolarizationdoes not occur, the zona pellucida does not

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degenerate, and other sperm cells can attach tothe oocyte membrane, leading to polyspermy.The approximate length of time the embryohas been developing, called the postovulatoryage, is 14 days less than the time since thelast menstrual period (LMP). In this case,the postovulatory age is 30 days (44 − 14).By this time, the neural tube has closed, thesomites have formed, the digestive tract isdeveloping, the limb buds have appeared, atubular beating heart is present, and the lungsare developing. Because reproductive struc-tures are still just forming, male and femaleembryos are indistinguishable at this age.The fever occurred on days 21–31 of devel-opment, during the time of neural tubeclosure (days 18–25). If the fever preventedneural tube closure, the child could be bornwith anencephalus or spina bifida.Progesterone reduces the release of oxytocin,the hormone that stimulates uterine contrac-tions. Also, progesterone reduces the numberof oxytocin receptors in the uterus. Theseeffects reduce labor contractions and canprevent preterm delivery.The Apgar score of 5 indicates appear-ance (A, 0) white or blue; pulse (P, 1) low;grimace (G, 1) slight; activity (A, 1) littlemovement and poor muscle tone; and res-piration (R, 2) normal. The white or blueappearance (A, 0) is consistent with a poorcirculation, as also indicated by reducedpulse (P, 1). The reduced heart rate, result-ing in the low pulse, may indicate a circula-tory system problem. The reduced reflexesand motor activity (G, 1; A, 1) can resultfrom lack of oxygen in the muscles due topoor circulation. Because the infant haspoor circulation despite normal respira-tion, clearing the airway (if obstructed) andadministering oxygen are in order. ThisApgar score can have several causes, andadditional information would be necessaryto determine the specific cause.Suckling the breast stimulates the releaseof oxytocin from the neurohypophysis (pos-terior pituitary). Once the oxytocin

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is in the blood, it travels to both breastsand causes milk letdown.The woman most likely has an XY genotype.The spherical structures in the inguinal areaare testes, but a genetic abnormality causedthe androgen receptors to be defective orabsent. Consequently, reproductive structurescould not respond to androgens secreted bythe testes. The embryonic testes secretedmu l̈ lerian-inhibiting hormone, and thereforethe mu l̈ lerian duct system degenerated. Thisexplains the lack of a uterus and a cervix.Female external genitalia developed becauseof the absence of androgen receptors. Normalbreast development occurred because of thesmall amount of estrogen produced by theadrenal glands and because some testoster-one is converted to estrogen in peripheraltissues.Answer b is correct. Müllerian-inhibitinghormone causes the duct system that givesrise to female internal reproductive structuresto degenerate in male fetuses. If the hormoneis not effective, female internal reproductivestructures, such as oviducts and a uterus,develop, at least to some degree, alongwith internal male reproductive structures.Because the developing testes producetestosterone, male external reproductivestructures develop.It is not possible from this informationalone. If tongue rolling is designated T andthe inability to roll the tongue is designated t, then a Tt woman and a tt man have a 50%probability of having a Tt child and a 50%probability of having a tt child. Therefore,a man who cannot roll his tongue and awoman who can roll her tongue can havea child who can roll his or her tongue. Thisconnection alone, however, is not sufficientto establish paternity.A person with blood type AB has thegenotype I A I B but no i allele. A personwith blood type O has a genotype of ii .Because the AB parent has no i allele, anAB individual cannot be the parent of achild with blood type O.