Mammalian Physiology Exam Ch.27

Exam N ame___________________________________ SH ORT A N SWER. Wri te the wor d or phrase that best compl etes each statement or answ ers the questi on. Fi gure 27.1 U sing Figur e 27.1, match the following: 1) Spermatogonium. Answer: A 2) First cells w ith n number of chromosomes. Answ er: D 3) Type B daughter cell. Answ er: B 1 4) Early spermatids. Answ er: E 5) Primary spermatocyte. Answ er: C Fi gure 27.2 Using Figure 27.2, match the following: 6) Location of acrosome. Answ er: B 7) Location of mitochondria. Answ er: A 8) M idpiece. Answ er: A 9) Location of nucleus. Answ er: C 10) Area of compacted DN A . Answ er: C 2 11) Flagellum. Answ er: D Fi gure 27.3 Using Figure 27.3, match the following: 12) The stage called ovulation. Answ er: E 13) Vesicular (Graafian) follicle. Answ er: C 14) Primary folli cles. Answ er: B 15) Primordial follicle. Answ er: A 16) Corpus luteum. Answ er: D 17) M ature follicle. Answ er: C 3 M A TCH IN G. Choose the item in col umn 2 that best matches each item in col umn 1. M at ch the following: 18) Homologous chromosomes separate. Answ er: A 19) Tetrads align randomly on the spindle equator. Answ er: C 20) Chromosomes that have undergone crossing over line up individually along the spindle equator. A) Anaphase I of meiosis B) M etaphase of mitosis C) M etaphase I of meiosis D) M etaphase II of meiosis E) A naphase II of meiosis Answ er: D 21) Chromosomes that have not undergone crossing over line up individually along the spindle equator. Answ er: B 22) Centromeres separate. Answ er: E 23) Part of a process that produces genetically identical daughter cells. Answ er: B M at ch the following: 24) Human papillomavirus. Answ er: D 25) Treponema pallidum. Answ er: A 26) Causes urethritis in males. Answ er: B 27) H uman herpes simplex virus. A) Syphilis B) Gonorrhea C) Chlamydia D) Genital warts E) Genital herpes Answ er: E 28) Pathogen responsible for 25- 50% of all diagnosed cases of pelvic inflammatory disease. Answ er: C 4 TRUE/FALSE. Wri te 'T' if the statement is true and 'F' if the statement is f al se. 29) It is necessary for the testes to be kept below body temperature for abundant, viable sperm formation. Answ er: True False 30) The prostate atrophies as a man ages, and it usually causes no health problems. Answ er: True False 31) When it is cold, the scrotum is pulled aw ay from the body. Answ er: True False 32) When a couple is having difficulty conceiving a child, it is necessary to investigate the sperm of the male. Answ er: True False 33) The amount of testosterone and sperm produced by the testes is dependent on the influence of FSH alone. Answ er: True False 34) Ovarian follicles contain mature eggs. Answ er: True False 35) Sexually transmitted infections are the most important cause of reproductive disorders. Answ er: True False 36) The testis is divided into seminiferous tubules which contain the lobules that produce sperm and the ejaculatory duct that allow s the sperm to be ejected from the body. Answ er: True False 37) The smaller cell produced by oogenesis meiosis I, called the first polar body, is essentially a packet of discarded nuclear material. Answ er: True False 38) A human egg or sperm contains 23 pairs of chromosomes. Answ er: True False 39) The Pap smear is a test to detect cancerous changes in cells of the cervix. Answ er: True False 40) The adenohypophyseal hormone that triggers ovulation is estrogen. Answ er: True False 41) Ovulation occurs near the end of the ovarian cycle. Answ er: True False 42) The corpus luteum secretes progesterone only. Answ er: True False 43) Female orgasm is required for conception. Answ er: True False 5 44) The first sign of puberty in females is budding breasts. Answ er: True False 45) Sustentocytes prevent sperm antigens from entering the bloodstream. Answ er: True False 46) The stage in meiosis w here chromosomal exchange takes place is telophase I. Answ er: True False 47) M ale erection is a response to a parasympathetic reflex, and ejaculation is a response to a sympathetic reflex. Answ er: True False 48) The soft mucosal lining of the uterus is the endometrium. Answ er: True False 49) A scrotal muscle that contracts in response to cold environmental temperature is the cremaster. Answ er: True False 50) The secretions of the bulbourethral glands neutralize traces of acidic urine in the urethra and serve as a lubricant during sexual intercourse. Answ er: True False 51) The zona pellucida is formed as the follicle becomes a secondary follicle. Answ er: True False 52) The molecule that enhances the ability of testosterone to promote spermatogenesis is inhibin. Answ er: True False 53) Sperm are ejaculated from the corpora cavernosa of the penis. Answ er: True False 54) M ale testicular functions are regulated by FSH and LH . Answ er: True False 55) Extremely stressful physical activity in young females can result in excessive bone mass due to large amounts of estrogen production. Answ er: True False M ULTI PLE CHOI CE. Choose the one alternati ve that best completes the statement or answ ers the question. 56) All of the following things occur during meiosis I. Select the statement below that does NOT occur during meiosis I. A) A single diploid (2n) nucleus has become two haploid (n) nuclei. B) The homologous chromosomes are separated from each other. C) Portions of maternal chromosomes crossover with equivalent portions of paternal chromosomes. D) The sister chromatids are separated from each other. Answ er: D 6 57) Which of the following statements is true of metaphase I of meiosis I? A) The sister chromatids line up randomly on the spindle equator with some maternal and paternal chromatids on both sides of the equator. B) Tetrads align randomly on the spindle equator with all the maternal homologs on one side and all the paternal homologs on the opposite side. C) Homologous pairs align randomly on the spindle equator with a mix of paternal and maternal homologs destined for each of the daughter cells. D) Joined homologous pair uniformly line up on the equatorial spindle with chromosome one at the top and chromosome 23 on the bottom. Answ er: C 58) Select the statement below that is FA LSE. A) M eiosis produces genetically unique cells while mitosis produces genetically identical cells. B) A cell undergoing meiosis results in 4 cells whi le a cell undergoing mitosis results in 2 cells. C) M eiosis results in haploid cells while mitosis results in diploid cells. D) M eiosis occurs only after the onset of puberty while mitosis occurs throughout an entire lifetime. Answ er: D 59) Select the statement w hich is true regarding independent assortment. A) Its effects are significant in meiosis and in mitosis. B) It only occurs in meiosis II. C) It is a significant source of genetic variation that occurs in meiosis I and meiosis II. D) It is a significant source of genetic variation only during meiosis I. Answ er: D 60) Select the statement which is FA LSE. A) Crossing over is a source of genetic variability seen in meiosis w hile independent assortment is a source of genetic variability seen in mitosis. B) M eiosis II is essentially the same process as mitosis except the genetic material will not replicate before division takes place. C) Further genetic variation typically does not occur after meiosis I. D) M eiosis II is essentially the same process as mitosis except the starting cells are haploid (n). Answ er: A 61) All but one of the follow ing statements are true regarding the differences betw een early and late spermatids. Select the answ er below that does NOT reflect a difference betw een early and late spermatids. A) Early spermatids have not undergone spermiogenesis. B) Early spermatids have not formed flagella. C) Early spermatids have not undergone meiosis and are still diploid. D) Early spermatids are round and have excessive cytoplasm. Answ er: C 7 62) During spermiogenesis ________. A) the acrosome migrates towards the posterior end of the spermatid because of its ability to propel the flagella moving the sperm through the female reproductive system tow ards the egg B) the acrosome migrates towards the anterior end of the spermatid because its pointy shape helps the sperm to move more efficiently C) the acrosome migrates tow ards the anterior end of the spermatid because its hydrolytic enzymes w ill be needed for penetration when the sperm contacts the egg during fertilization D) the acrosome migrates tow ards the posterior end of the spermatid because its hydrolytic enzymes w ill be needed for digestion of the excessive cytoplasm around the flagella of the developing sperm Answ er: C 63) All but one of the events described below occur during spermiogenesis. Select the event that does NOT occur during spermiogenesis. A) Mitochondrial DN A is packaged into the nucleus to be delivered to the egg during fertilization. B) The centrioles migrate to the posterior end of the developing sperm to form the microtubules that make up the flagellum. C) Excessive cytoplasm will be shed to reduce unneeded mass of the maturing sperm. D) Mitochondria form around the proximal end of the flagellum. They w ill provide the ATP to drive the motion of the flagellum. Answ er: A 64) All but one of the follow ing statements is true with regard to the blood testis barrier. Select the one statement that is FA LSE. A) The barrier prevents the spermatocytes from exposing their unique antigens to the immune system. B) The barrier is made up of astrocytes that surround blood vessels in the testis. C) The cells that form the blood testis barrier are joined by tight junctions. D) The barrier marks the border between the basal compartment and the adluminal compartment. Answ er: B 65) Of the following statements, select the statement that is N OT true of uterine function. A) The narrow portion of the uterus near the cervix is the most typical site of fertilization. B) The endometrium has a functional layer that the embryo will implant into. C) The myometrium contracts to expel the fetus during childbirth. D) The rhythmic, reverse peristalsis of the uterus can propel sperm toward the egg. Answ er: A 66) The oral contraceptive pill, informally called "the pill," contains an estrogen and progesterone, or a synthetic mimic of this hormone. The combination of these tw o hormones, taken in the pill and circulating in the blood, w orks because ________. A) the hormones prevent the proliferative or secretory phase of the menstrual cycle and the embryo will have no place to implant B) the hormones cause the w oman's body to mimic the activities of a pregnancy and disrupt the ovarian cycle, preventing ovulation C) the hormones create an acid condition in the vagina that acts as a spermicide D) the hormones cause a thickening of the mucus plug at the cervix that prevents sperm from penetrating the w omb and reaching the ovulated egg Answ er: B 8 67) The diploid number of chromosomes in a human is 46. Therefore, the number of chromosomes in a primary spermatocyte or primary oocyte is ________. A) 92 B) 46 C) 23 D) 38 Answ er: B 68) The dartos and cremaster muscles are important to the integrity of the male reproductive system. Which of the follow ing best describes the role they play? A) They regulate the temperature of the testes. B) They contract to push sperm along the ductus deferens. C) They contract to allow ejaculation. D) They are responsible for penile erection. Answ er: A 69) The ability of sperm cells to move along the ductus deferens is due to ________. A) peristaltic contractions B) enzymatic activity C) hormonal action D) gravity Answ er: A 70) The most important risk for testicular cancer in young males is ________. A) sexually transmitted infections B) smoking C) a diet high in fat D) failure of the testis to make their normal descent Answ er: D 71) Which of the following glands are responsible for producing 70% of semen volume? A) the seminal vesicles B) the pituitary C) the prostate D) the bulbourethral glands Answ er: A 72) Which of the following hormones controls the release of anterior pituitary gonadotropins? A) GnRH B) testosterone C) FSH D) LH Answ er: A 73) The critical factor that determines gender during development is ________. A) lack of an X chromosome B) the SRY gene C) presence of progesterone D) inhibition of estrogen Answ er: B 74) The structures that receive the ovulated oocyte, providing a site for fertilization, are called the ________. A) Graafian follicles B) uterine tubes C) fimbriae D) infundibula Answ er: B 9 75) If gametes were diploid like somatic cells, how many chromosomes would the zygote contain? A) Half the diploid number with no change in development. B) Triple the diploid number, and with every succeeding generation, the chromosome number would continue to triple and normal development w ould not occur. C) Tw ice the diploid number, and with every succeeding generation, the chromosome number would continue to double and normal development could not occur. D) There is no relationship betw een gametes and somatic cells. Answ er: C 76) H uman egg and sperm are similar in that ________. A) about the same number of each is produced per month B) they have the same number of chromosomes C) they are about the same size D) they have the same degree of motility Answ er: B 77) The constancy of the chromosome number from one cell generation to the next is maintained through ________. A) meiosis B) cytokinesis C) DN A synthesis D) mitosis Answ er: A 78) Fertilization generally occurs in the ________. A) vagina B) ovary C) uterus D) uterine tubes Answ er: D 79) Which of the following female structures is homologous to the male scrotum? A) labia minora B) clitoris C) vagina D) labia majora Answ er: D 80) In humans, separation of the cells at the tw o- cell state follow ing fertilization may lead to the production of tw ins, which in this case would be ________. A) genetically identical B) potentially of different sexes C) dizygotic D) fraternal Answ er: A 81) Which of the follow ing is incurable? A) gonorrhea B) trichomoniasis C) syphilis D) genital herpes Answ er: D 82) Effects of estrogen include ________. A) growth of the larynx C) growth of the breasts at puberty B) increased oiliness of the skin D) deepening of the voice Answ er: C 83) Secretion of progesterone stimulates ________. A) development of the female secondary sex characteristics B) contraction of uterine muscles C) preparation of the mammary glands for lactation D) proliferation of the uterine myometrium Answ er: C 10 84) The cells that produce testosterone in the testis are called ________. A) interstitial endocrine cells B) spermatocytes C) sustentacular cells D) spermatogonia Answ er: A 85) If a woman has just ended her menstrual phase, w hen is she most likely to ovulate? A) in about 24 days B) within the next 4 days C) in about 14 days D) in about 10 days Answ er: C 86) Erection of the penis results from ________. A) dilation of the veins in the penis B) a sympathetic activation of bulbospongiosus muscles C) parasympathetic activation of the bulbourethral glands D) a parasympathetic reflex that promotes release of nitric oxide Answ er: D 87) Which is NOT a part of the proliferative phase of the female menstrual cycle? A) corpus luteum secretion B) vesicular follicle grow th C) development of endometrial cells D) late in this phase, cervical mucus becomes thin and crystalline Answ er: A 88) Which of the choices below is NOT a function of the vagina? A) serves as the birth canal B) receives semen from the penis during sexual intercourse C) serves as a passagew ay for menstrual flow D) serves as a passagew ay for the primary oocyte Answ er: D 89) Which of the following is true of testosterone? A) Testosterone is produced by interstitial endocrine cells. B) The release of testosterone surges during ejaculation. C) Testosterone provides positive feedback on gonadotropin release. D) The production of testosterone is stimulated by FSH. Answ er: A 90) Which of the choices below is NOT a function of testosterone? A) contributes to male sexual behavior and spermatogenesis B) stimulates the HPG axis C) stimulates the male pattern of development D) stimulates protein synthesis Answ er: B 91) Which male hormone provides negative feedback for the secretion of FSH? A) inhibin B) GnRH C) A CTH Answ er: A 11 D) ICSH 92) During the secretory phase of the menstrual cycle, ________ reaches its highest levels. A) LH B) progesterone C) FSH D) estrogen Answ er: B 93) Select the correct statement about the uterine cycle. A) If fertilization occurs, the corpus luteum is maintained by a hormone secreted by the developing embryo. B) The menstrual phase of the cycle is normally from day 1 to day 8. C) During the secretory phase, estrogen levels are at their highest. D) During the proliferative phase, levels of progesterone rise as the follicle produces more hormone. Answ er: A 94) Which of the choices below is NOT a part of the hypothalamic- pituitary- gonadal axis? A) thalamus B) hypothalamus C) interstitial cells D) anterior pituitary gland Answ er: A 95) Which of the follow ing statements is true concerning the mammary glands of both males and females? A) The only time hormones target breast tissue is during pregnancy and lactation. B) Both sexes are equally prone to breast cancer. C) A ll lumps identified in breast tissue are malignant. D) The mammary glands are modified sw eat glands that are part of the integumentary system. Answ er: D 96) Normally menstruation occurs when ________. A) blood levels of estrogen and progesterone decrease B) blood levels of estrogen and progesterone increase C) blood levels of FSH fall off D) the corpus luteum secretes estrogen Answ er: A 97) The basic difference betw een spermatogenesis and oogenesis is that ________. A) in oogenesis, one mature ovum is produced from the parent cell, and in spermatogenesis four mature sperm are produced from the parent cell B) during spermatogenesis tw o more polar bodies are produced C) the mature ovum is n, w hile the sperm is 2n D) spermatogenesis involves mitosis and meiosis, but oogenesis involves meiosis only Answ er: A 98) Occasionally three polar bodies are found clinging to the mature ovum. One came from an unequal division of the ovum, but from where did the other tw o arise? A) There were originally four polar bodies and one disappeared. B) The first polar body has also divided to produce tw o polar bodies. C) What you really see are tw o polar bodies and the sperm that will fertilize the egg. D) One is an undeveloped primary oocyte that failed to mature. Answ er: B 12 99) Which of the follow ing will occur immediately after ovulation? A) The corpus luteum becomes a corpus albicans. B) The endometrium enters its secretory phase. C) The secretion of anterior pituitary gonadotropins is enhanced. D) The corpus luteum secretes estrogen only. Answ er: B 100) Why doesn't semen enter the urinary bladder during ejaculation? A) The smooth muscle sphincter at the base of the urinary bladder closes. B) Ejaculation is a parasympathetic reflex that activates urinary contraction muscles. C) There is no common duct between the reproductive system and the urinary system. D) There is no urge to urinate during sexual intercourse because of the suppression of LH by testosterone buildup in the blood. Answ er: A 101) Spermatogenesis ________. A) is the process of releasing mature sperm cells into the lumen of the seminiferous tubule B) involves a tw o- part process called mitosis I and mitosis II C) results in the formation of diploid cells D) involves a kind of cell division limited to the gametes Answ er: D 102) Which hormone is the necessary trigger for ovulation to occur? A) estrogen B) LH C) FSH Answ er: B 103) The hypothalamic- pituitary- gonadal axis ________. A) involves the release of testosterone from the anterior pituitary B) involves posterior pi tuitary release of tw o regulating hormones C) involves FSH and LH release from the anterior pituitary D) involves positive feedback control of spermatogenesis Answ er: C 104) Which of the follow ing does NOT occur in both the male and female sexual response? A) Blood pressure and heart rate increase. B) Blood flow to genital structures increases. C) A refractory period follow s orgasm. D) Muscles of structures in the reproductive duct contract rhythmically. Answ er: C 105) Which of the following is a correct statement about uterine tubes? A) The isthmus is the normal site of fertilization. B) The mesometrium supports the uterine tubes along their entire length. C) The ampulla is the narrow constricted region. D) The infundibulum is the funnel- shaped region near the ovary. Answ er: D 13 D) progesterone 106) Select the correct statement about the hormonal events of the ovarian cycle. A) High estrogen levels result in a surge of LH release. B) The LH surge stimulates further development of the secondary oocyte. C) The follicle begins to secrete progesterone in response to estrogen stimulation. D) Rising levels of estrogen start follicle development. Answ er: A 107) Which of these statements about sexually transmitted infections is FA LSE? A) Syphilis is caused by a virus that may lead to death if untreated. B) Gonorrhea is caused by a bacterium that can bring on painful discharges in males. C) Chlamydia is caused by bacteria that can often be asymptomatic or bring on a w ide variety of symptoms. D) Genital herpes is caused by a virus that may cause intermittent lesions. Answ er: A 108) Which of the follow ing statements about spermatogenesis is NOT true? A) The secondary spermatocytes each form two spermatids. B) Each spermatid forms tw o sperm. C) The primary spermatocyte forms tw o secondary spermatocytes. D) The spermatogonium forms the primary spermatocyte. Answ er: B 109) A boy who has not passed through puberty sustains an injury to his anterior pituitary such that FSH is no longer released, but LH is normal. A fter he grow s to maturity, one would expect that he would ________. A) have impaired function of interstitial cells B) be impotent (unable to have an erection) C) be unable to produce viable sperm D) not develop secondary sex characteristics Answ er: C 110) A patient w ith trichomoniasis, if they have any symptoms at all, w ill most likely exhibit which of the following? A) yellow- green vaginal discharge and strong odor B) painful lesions on the genitals C) pink rash all over the body D) sterility Answ er: A 111) A low secretion of luteinizing hormone (LH ) in the normal male adult would cause ________. A) shrinkage of the anterior pituitary gland B) decreased testosterone secretion C) excessive beard grow th D) increased spermatogenesis Answ er: B 112) All of the follow ing statements referring to the uterine cycle are true EXCEPT ________. A) the corpus luteum is formed from the ruptured follicle after ovulation B) FSH and LH directly promote development of the uterine endometrium C) a decrease in the levels of ovarian hormones signals menstruation D) estrogen is secreted by the developing follicle in the follicular phase of the cycle Answ er: B 14 113) Which of the follow ing phases or processes in the monthly reproductive cycle of the female occur simultaneously? A) early follicular development and the secretory phase in the uterus B) maximal LH secretion and menstruation C) maximal steroid secretion by the corpus luteum and menstruation D) regression of the corpus luteum and a decrease in ovarian progesterone secretion Answ er: D 114) The duct system of the male reproductive system includes all but which of the follow ing? A) epididymis B) urethra C) corpus spongiosum D) ductus deferens Answ er: C 115) Prostate cancer is ________. A) sometimes a slow - grow ing cancer that may never represent a threat to the patient B) often the result of a distortion of the urethra C) the number one cause of death in men D) most common in Asians Answ er: A SH ORT A N SWER. Wri te the word or phrase that best compl etes each statement or answ ers the question. 116) The ________ plexus of testicular veins assists in cooling the testis. Answ er: pampiniform 117) Surgical cutting of the ductus deferens as a form of birth control is called a(n) ________. Answ er: vasectomy 118) The erectile tissue around the urethra is the corpus ________. Answ er: spongiosum 119) The midpiece of the sperm tail contains mostly ________. Answ er: mitochondria 120) The ________ of the testis nourish the newly formed sperm cells. Answ er: sustenocytes 121) The suspensory ligament and mesovarium are part of the ________ ligament. Answ er: broad 122) A follicle with only a small antrum in it w ould be classified as a(n) ________ follicle. Answ er: secondary 123) The portion of the uterine endometrium that is not sloughed off every month is called the ________. Answ er: stratum basalis 124) Treponema pallidum causes the sexually transmitted disease called ________. Answ er: syphilis 15 125) What are some risk factors for developing breast cancer? Answ er: Some of the risk factors for developing breast cancer are: (1) early onset of menses and late menopause; (2) first pregnancy late in life or no pregnancies at all; (3) familial history of breast cancer; (4) postmenopausal hormone replacement. 126) What is the name given to the female homologue to the penis? Answ er: The female clitoris is homologous to the glans penis of the male. It is homologous in that it contains dorsal erectile columns and can become sw ollen with blood during tactile stimulation. 127) Describe the composition and functional roles of semen. Answ er: Semen is a fluid mixture of sperm and accessory gland secretions (prostate, seminal vesicles, and bulbourethral glands). The liquid provides a transport medium for nutrients and contains chemicals that protect the sperm and facilitate their movements. 128) Explain the function of the myometrium and endometrium. Answ er: The myometrium plays an active role during childbirth when it contracts rhythmically to force the baby out of the mother's body. The endometrium is the innermost lining of the uterus that nourishes the embryo from the time of implantation until delivery. 129) What is the purpose of the male bulbourethral gland? Answ er: Because it releases its contents prior to ejaculation, its function is probably to neutralize the acids in the urethra and for lubrication to help the initiation of intercourse. 130) What is the physiological importance of the fact that the male testes descend to reside in the scrotal sac? Answ er: The male testes descend into the scrotal sac so that a fairly constant intrascrotal temperature is maintained. Failure of the testes to descend results in sterility, because production of viable spermatozoa requires a temperature several degrees lower than normal body temperature, and also increases the incidence of testicular cancer. 131) Ovulation occurs when the oocyte is released into the peritoneal cavity. By what means does it usually enter the uterine tube? Answ er: Fimbriae, which drape over the ovary, become very active close to the time of ovulation and their cilia create currents in the peritoneal fluid. These currents usually carry the oocyte to the uterine tube, w here it begins its journey tow ard the uterus. 132) At w hat point is the sex of the embryo determined, and w hat determines it? Answ er: Genetic sex is determined at the instant the genes of a sperm combine with those of an ovum. The determining factor is the sex chromosomes each gamete contains. ESSA Y. Wri te your answ er in the space provi ded or on a separate sheet of paper. 133) Teresa has been complaining of severe abdominal pain, vagi nal discharge, and a low - grade fever. What might be the doctor's diagnosis, and how should the condition be treated? Answ er: The symptoms sound like pelvic inflammatory disease (PID), a collective term for any extensive bacterial infection of the pelvic organs, especially the uterus, uterine tubes, or ovaries. PID at one time was most commonly caused by the bacterium that causes gonorrhea, but any bacterium can trigger the infection. Early treatment should include antibiotics (doxycycline or a cephalosporin). 16 134) A 38- year- old male is upset about his low sperm count and visits a "practitioner" w ho commonly advertises his miracle cures of sterility. The practitioner is a quack who treats conditions of low sperm count with megadoses of testosterone. Although his patients experience a huge surge in libido, their sperm count is even low er after hormone treatment. Explain why. Answ er: Megadoses of testosterone would inhibit hypothalamic release of GnRH and may act directly on the anterior pituitary to inhibit gonadotropin (FSH ) release. Spermatogenesis is inhibited in the absence of FSH stimulation. 135) Debbye has been having pelvic pain, especially during her monthly period, for many months. She has been to several doctors and they all tell her that she is just experiencing extra- heavy monthly flows. The tests all turn up negative. She has been trying to conceive but nothing works. What could the problem be? Answ er: Debbye likely has endometriosis. This problem is very difficult to diagnose and every case is different. Generally it requires laparoscopic view s to find the problem. Endometriosis can cause sterility by cycles of endometrial cell grow th and death, leading to inflammation follow ed by scar formation that in turn may block the uterine tubes, w hich prevents the sperm from getting to the egg or the egg from getting to the uterus. 136) Based on your knowledge of how the prostate encircles part of the urethra, w hat are tw o clinical manifestations of an enlarged prostate? Answ er: A w akening at night to void caused by incomplete bladder emptying from an enlarging prostate; a small urinary stream; hesitancy in starting the urinary stream; dribbling at the end of voiding. 137) A woman, w hose family history contains severe osteoporosis, asked her doctor to prescribe estrogen after she reached menopause to reduce her risk of osteoporosis. The doctor refused to provide long- term estrogen replacement therapy. Why? Answ er: The risk of breast cancer is proportional to a woman's lifetime exposure to estrogens. It w ould be better for her to find alternative treatments to reduce her risk of osteoporosis than to increase her risk of breast cancer from long- term estrogen supplementation. 138) Explain the action of drugs like sildenafil (Viagra) on the male reproductive system. Answ er: Sildenafil and other similar drugs enhance the effect of nitric oxide on the reproductive tissues. N itric oxide relaxes smooth muscle in the blood vessels of the penis, dilating the vessels and allow ing erectile tissues to fill with blood. This enhanced action of engorging the corpora cavernosa and corpora spongiosum enhances and prolongs erections. 139) What are some possible complications a patient may have after a radical mastectomy? Answ er: The entire breast is removed along w ith underlying muscles, fascia, and associated lymph nodes. Therefore, the patient might experience lymphedema related to edema on the operative side. The patient may also experience problems with arm function due to the removal of muscles. The patient might experience muscle shortening and decreased muscle tone of other muscles on the affected side. 17