Chapter 9: Reproductive Behavior 9.1 Multiple Choice 1) After his penis was destroyed at age 7 months in a botched circumcision procedure, Bruce (the subject of the chapter prologue) A) then became Brenda. B) retained a male identity. C) received regular injections of testosterone from age 15 to 30 D) was given a penile implant at age 5. E) received estrogen pills starting at age 5. Answer: A 2) ________ is an example of a sexually dimorphic behavior. A) Mating B) Eating C) Drinking D) Driving a vehicle E) Language Answer: A 3) Gametes are mature reproductive cells that A) will eventually form the sex organs of the fetus. B) secrete Müllerian inhibiting substance. C) carry half the genetic information of other cells of the body. D) are formed by the union of an egg and a sperm during fertilization. E) contain 23 pairs of chromosomes. Answer: C 4) Which of the following biological factors determines the genetic sex of a fetus? A) the gonads of the fetus B) a single gene on the X chromosome C) the hormones produced by the pituitary during fetal development D) the father's sperm E) the phase of the menstrual cycle during which fertilization occurs Answer: D 5) Which of the following is true of the sex chromosomes? A) The Y chromosome controls the development of the male sex glands. B) The Y chromosome contains the blueprints for male fetus development. C) The Y chromosome contains the blueprints for the female fetus. D) The mother donates her Y chromosome to form a female fetus. E) The sex chromosomes are the largest among the 23 pairs. Answer: A 6) Which of the following is considered to be a sexual organ? A) ovaries and testes B) brain C) hair D) chromosomes E) Sry gene Answer: A Rationale: The ovaries and testes are sexual organs. 7) The protein that dictates the conversion of the undifferentiated gonads into the testes is controlled by the A) gene Tny. B) leptin protein. C) ob/ob gene. D) gene Sry. E) X chromosome. Answer: D 8) Which biological factor below is required to form the ovaries? A) the Y chromosome. B) the Sry gene C) the X chromosome D) testosterone E) No factor is required. Answer: E Rationale: No factor is required to form the ovaries. 9) An example of an activational effect of the hormone estradiol is A) growth of the uterine lining during the menstrual cycle. B) maturation of the ovaries. C) differentiation of the Wolffian system into the fimbriae, Fallopian tubes, uterus, and vagina. D) growth of auxiliary hair in females. E) alteration of the vocal cords to create a "deep" voice. Answer: A Rationale: An example of an activational effect of the hormone estradiol is growth of the uterine lining during the menstrual cycle. 10) The difference between an organizational hormone effect and an activational hormone effect is that A) organizational effects only occur in the brain. B) organizational effects are permanent. C) organizational effects only occur during adulthood. D) activational effects are mediated by receptors, whereas organizational effects are due to changes in neurotransmitter secretion. E) activational effects are permanent. Answer: B Rationale: The difference between an organizational hormone effect and an activational hormone effect is that organizational effects are permanent. 11) The structures that comprise the Müllerian system are the precursors to the A) penis and scrotum. B) ovaries. C) female internal sex organs. D) testes. E) male internal sex organs. Answer: C 12) The Wolffian system structures are the precursors to the A) male internal sex organs. B) penis and scrotum. C) female internal sex organs. D) testes. E) ovaries. Answer: A 13) The prenatal development of the internal reproductive structures of the male requires A) suppression of the Müllerian system by anti-Müllerian hormone. B) secretion of estradiol by the pituitary. C) secretion of progesterone D) secretion of estradiol. E) A and D are correct. Answer: E 14) The prenatal development of the internal reproductive structures of the female requires A) secretion of progesterone. B) secretion of estradiol by the pituitary. C) suppression of the Müllerian system by anti-Müllerian hormone. D) secretion of androgens. E) no stimulus. Answer: E 15) A hormone that prevents the prenatal development of the Müllerian system is said to have a(n) A) masculinizing effect. B) activational effect. C) defeminizing effect. D) feminizing effect. E) non-selective action on the undifferentiated gonads. Answer: C Rationale: A hormone that prevents the prenatal development of the Müllerian system is said to have a defeminizing effect. 16) An androgen that promotes the prenatal development of the Wolffian system is said to have a(n) A) non-selective action on the undifferentiated gonads. B) activational effect. C) masculinizing effect. D) feminizing effect. E) defeminizing effect. Answer: C Rationale: An androgen that promotes the prenatal development of the Wolffian system is said to have a masculinizing effect. 17) ________ has a defeminizing action during human prenatal development. A) Testosterone B) Dihydrotestosterone C) Estradiol D) Androgen E) Anti-Müllerian hormone Answer: E 18) The prenatal development of the internal reproductive structures of the female A) requires the suppression of the Müllerian system by anti-Müllerian hormone. B) requires secretion of estradiol by the pituitary. C) is caused by secretion of progesterone. D) requires no hormone. E) requires functional anti-Müllerian receptors. Answer: D 19) All of the following are characteristics of untreated androgen insensitivity syndrome EXCEPT A) female external genitals. B) testes. C) breast growth at puberty. D) female internal genitals. E) the inability to have children. Answer: D 20) In which disorder would you expect to observe testes as well as the external genitals of a female? A) persistent Müllerian duct syndrome B) Turner's syndrome C) Sry syndrome D) adrenogenital syndrome E) androgen insensitivity syndrome Answer: E Rationale: In androgen insensitivity syndrome you would expect to observe testes as well as the external genitals of a female. 21) In which disorder would you expect to observe the external genitals of a male in conjunction with both male and female internal reproductive structures? A) adrenogenital syndrome B) Turner's syndrome C) Sry syndrome D) persistent Müllerian duct syndrome in a genetic male E) androgen insensitivity syndrome Answer: D Rationale: In persistent Müllerian duct syndrome in a genetic male you would expect to observe the external genitals of a male in conjunction with both male and female internal reproductive structures. 22) People with Turner's syndrome A) lack steroid receptors. B) have no gonads. C) develop male internal sex organs. D) have two Y chromosomes and one X chromosome. E) are prolific at bearing children. Answer: B 23) The major principle illustrated by Turner's syndrome is that A) different hormones are required to develop or to suppress the development of the male reproductive organs. B) female secondary sexual characteristics appear without the ovaries. C) ovaries are necessary for development of the Müllerian system. D) ovaries are NOT necessary for development of the Müllerian system. E) male fetuses produce Müllerian-inhibiting substance. Answer: D Rationale: The major principle illustrated by Turner's syndrome is that ovaries are NOT necessary for development of the Müllerian system. 24) The prenatal development of the external male genitalia requires the presence of A) estradiol. B) melatonin. C) alpha-fetoprotein. D) dihydrotestosterone. E) anti-Müllerian hormone. Answer: D 25) An example of a primary sex characteristic is ________, while ________ are an example of a secondary sex characteristic. A) estrogen; the external genitals B) wide hips; internal sex organs C) a deep voice; the gonads D) the gonads; enlarged breasts E) a beard; the external genitals Answer: D 26) Which of the following pairs represent an example of a primary sex characteristic and an example of a secondary sex characteristic? A) penis; beard growth B) enlarged breasts; wide hips C) testes development; ovaries D) clitoris; ovaries E) deep voice; beard growth Answer: A Rationale: A penis is an example of a primary sex characteristic while beard growth is an example of a secondary sex characteristic. 27) Which of the following events takes place at the onset of puberty to start sexual maturation? A) LH and FSH are released from the gonads. B) Estradiol and testosterone are released by the gonads. C) The pituitary secretes gonadotropin-releasing hormones. D) The ovaries and testes release gonadotropic hormones. E) Sexual maturation is not a hormonally dependent process. Answer: B 28) An effect of estrogens during puberty is A) beard growth. B) growth of pubic hair. C) lowering of the voice. D) promotion of muscle development. E) breast development. Answer: E 29) Which of the following is NOT an effect of androgens during puberty? A) altering the hairline of the head B) changes in the deposition of body fat C) lowering of the voice D) beard growth E) promotion of muscle development Answer: B 30) The growth of pubic and auxiliary hair in male and female humans is promoted by A) androgens secreted from the adrenal cortex. B) corticosterone. C) estrogens secreted from the adrenal cortex. D) progesterone. E) leptin. Answer: A 31) The key difference that distinguishes the menstrual cycle from an estrous cycle is that A) the estrous cycle is longer than the menstrual cycle. B) females can only mate around the time of ovulation in the menstrual cycle. C) there is no cycle of growth/loss of the uterine lining in the estrous cycle. D) the estrous cycle does not involve the secretion of estrogens. E) females can mate at any time during the estrous cycle. Answer: C Rationale: The key difference that distinguishes the menstrual cycle from an estrous cycle is that there is no cycle of growth/loss of the uterine lining in the estrous cycle. 32) Which of the following is true of the estrous cycle of rats? A) Removal of the ovaries does not disrupt the estrous cycle once it has been established in the adult female. B) The estrous cycle is controlled by adrenal hormones. C) Ovulation is not required for sexual behavior during the estrous cycle. D) The estrous cycle lasts 4 days. E) The uterine lining is lost on day 4 of the cycle. Answer: D 33) A key effect of luteinizing hormone is to A) promote the growth of the ovarian follicles. B) assist implantation of the fertilized ovum. C) facilitate beard growth. D) induce ovulation. E) induce the growth of auxiliary hair. Answer: D Rationale: A key effect of luteinizing hormone is to induce ovulation. 34) Ovulation involves a surge in ________ which in turn ________. A) leptin; promotes the loss of the uterine lining B) estrogen; disrupts the ovarian follicle C) estradiol; promotes the longevity of the uterine lining D) follicle-stimulating hormone; causes the release of luteinizing hormone E) luteinizing hormone; disrupts the ovarian follicle Answer: E 35) Menstruation is triggered by A) reduced secretion of estradiol and progesterone from the corpus luteum. B) a surge of androgens from the adrenal cortex. C) implantation of a fertilized ovum in the uterus. D) a surge of estrogens from the adrenal cortex. E) increased secretion of estrogen and progesterone from the corpus luteum. Answer: A 36) Which of the following is true of male sexual behavior? A) Pelvic thrusting is limited to males. B) Ejaculation refers to the discharge of semen from the penis. C) Intromission refers to a break between bouts of sexual behavior. D) Orgasm requires intromission. E) The sexual behavior of human males requires high levels of testosterone. Answer: B 37) A key aspect of the Coolidge effect is that exposure to a novel female A) fails to elicit sexual satiety. B) lengthens the sexual refractory period after ejaculation. C) diminishes the sexual refractory period after ejaculation. D) elicits motor responses that are incompatible with intromission. E) reduces the circulating levels of testosterone in the male rat. Answer: C Rationale: A key aspect of the Coolidge effect is that exposure to a novel female diminishes the sexual refractory period after ejaculation. 38) The ________ effect refers to a situation in which a novel female will elicit another bout of sexual behavior in a sexually satiated male rat. A) Whitten B) Lee-Boot C) Vandenbergh D) Coolidge E) Bruce Answer: D 39) Sexual behavior in the male rat is maintained by adequate levels of A) testosterone. B) luteinizing hormone. C) growth hormone. D) vasopressin. E) ghrelin. Answer: A 40) All of the following are active sexual behaviors displayed by female rodents EXCEPT A) approaching the male. B) ear wiggling. C) intromission. D) rapid hopping movements. E) lordosis. Answer: C 41) The function of lordosis in a female mammal is to A) prepare the female for a rapid escape response from the male. B) expose the male rat to vaginal pheromones. C) prevent sexual contact with the male rat. D) facilitate intromission by the male rat. E) trigger ovulation. Answer: D Rationale: The function of lordosis in a female mammal is to facilitate intromission by the male rat. 42) Which sequence of hormone treatment produces receptive behaviors in an ovariectomized female rat? A) a small dose of progesterone alone B) a small dose of oxytocin alone C) oxytocin dose followed thereafter by a progesterone dose D) a small dose of estradiol alone E) a small dose of estradiol followed thereafter by a progesterone dose Answer: E Rationale: A small dose of estradiol followed thereafter by a progesterone dose produces receptive behaviors in an ovariectomized female. 43) Which of the following conditions will block or diminish female rodent sexual behavior? A) damage to the lateral thalamus B) being in a nonestrous state C) targeted mutations of ghrelin receptors D) genetic ablation of the SRy gene. E) administration of estradiol followed by progesterone. Answer: B 44) Lordosis would be an example of ________ in the female rat. A) receptivity B) attractivity C) proceptivity D) perceptivity E) reactivity Answer: A 45) Physiological and behavioral changes in a female rat that alter the sexual interest of a male rat are termed _______ behaviors. A) refractory B) attractiveness C) perceptive D) proceptivity E) receptive Answer: B 46) A male rat is castrated immediately after birth and then given injections of estradiol and progesterone in adulthood. This male rat would be expected to A) exhibit enhanced inter-male aggression. B) attempt to copulate with a female in heat. C) show lordosis in response to another male. D) attempt to copulate with a nonestrous female. E) show maternal aggression. Answer: C Rationale: A male rat is castrated immediately after birth and then given injections of estradiol and progesterone in adulthood. This male rat would be expected to show lordosis in response to another male. 47) Lordosis is considered to be a A) male sexual behavior. B) female sexual behavior. C) reflexive behavior shown by males. D) proceptive behavior. E) voluntary behavior shown by females. Answer: B 48) A female rat is ovariectomized and then injected with testosterone immediately after birth. In adulthood, this rat is injected with estradiol and progesterone and placed in a cage with a male rat. This female rat will A) show evidence of maternal aggression. B) attempt to mount the male. C) show lordosis to the male rat. D) not show female sexual behaviors. E) show behavioral masculinization. Answer: D Rationale: A female rat is ovariectomized and then injected with testosterone immediately after birth. In adulthood, this rat is injected with estradiol and progesterone and placed in a cage with a male rat. This female rat will not show female sexual behaviors. 49) A female rat is ovariectomized and then injected with testosterone immediately after birth. In adulthood, this rat is injected with testosterone and placed in a cage with a receptive female rat. This female rat will A) show female sexual behaviors. B) attempt to mount the receptive female. C) show lordosis to the female rat. D) show evidence of maternal aggression. E) show intermale aggression. Answer: B Rationale: A female rat is ovariectomized and then injected with testosterone immediately after birth. In adulthood, this rat is injected with testosterone and placed in a cage with a receptive female rat. This female rat will attempt to mount the receptive female. 50) The principle that best describes an organizational effect of androgens that prevents an animal from showing female sexual behavior during adulthood is A) aromatization. B) masculinization. C) behavioral masculinization. D) feminization. E) behavioral defeminization. Answer: E 51) The principle that best describes an organizational effect of androgens that enables an animal to engage in male sexual behavior during adulthood is A) feminization. B) sexual orientation. C) behavioral masculinization. D) aromatization. E) behavioral defeminization. Answer: C 52) The critical period of development during which exposure to ________ organizes male and female sexual behavior in rats during adulthood is ________. A) estrogen; just after conception B) androgens; shortly after birth C) estrogen; during the estrous cycle D) androgens; during the estrous cycle E) progesterone; shortly after birth Answer: B Rationale: The critical period of development during which exposure to androgens organizes male and female sexual behavior in rats during adulthood is shortly after birth. 53) A pheromone is a A) substance used to create human perfumes. B) chemical that is released by one animal that affects the behavior of another member of the same species. C) hormone released from the gut after the ingestion of fat. D) chemical located on the tongue that binds with sugar. E) type of enzyme that deactivate cyclic nucleotides. Answer: B Rationale: A pheromone is a chemical that is released by one animal that affects the behavior of another member of the same species. 54) Imagine that you have developed a new pheromone that induces male subjects to approach females. You incorporate it into a perfume, name it Passion, and then begin your marketing plan. Which of the following precautions would you take as you introduce your pheromone-laced perfume to the market? A) You would not hand out free samples during the late summer/early fall. B) You would advertise in men's magazines. C) You would not hand out free samples of Passion during the winter cold and flu season. D) Your advertising would suggest that Passion leads to passion. E) You would not advertize in sporting magazines. Answer: C 55) The ________ effect refers to the situation in which a group of female mice that are housed together show a slowing down and then a termination of their estrous cycles. A) Coolidge B) Bruce C) Bruce-Lee D) Lee-Boot E) Whitten Answer: D 56) The ________ effect refers to the situation in which the odor of a male rodent will accelerate the onset of puberty in a female rodent. A) Bruce-Lee B) Bruce C) Coolidge D) Lee-Boot E) Vandenbergh Answer: E 57) The Whitten effect and the Vandenbergh effect are induced in a female rodent by exposure to ________ from a(n) ________. A) urine; intact male rodent B) ultrasounds; stranger C) urine; intact female rodent D) sweat; castrated male rodent E) sweat; pregnant female rodent Answer: A Rationale: The Whitten effect and the Vandenbergh effect are induced in a female rodent by exposure to urine from an intact male rodent. 58) Which statement best describes the Bruce effect? A) Group-housed female mice show slower estrous cycles. B) Spontaneous abortion in female mice is noted after exposure to the odor of a novel male. C) Group-housed female mice show a faster estrous cycle. D) Estrous cycles of group-housed female mice are synchronized after exposure to the odor of an intact male mouse. E) The odor of a male mouse accelerates the onset of puberty in a female mouse. Answer: B 59) The vomeronasal organ A) is critical for sexual behavior in dolphins. B) of a human is heavily innervated by neurons. C) is the receptive organ for pheromones. D) projects to the accessory optic area and then to the primary visual cortex. E) is found in all cetaceans such as whales and dolphins. Answer: C 60) Neurons of the vomeronasal organ project to the A) optic bulb. B) hypothalamus. C) somatosensory cortex. D) accessory olfactory bulb. E) frontal cortex. Answer: D 61) Damage to the accessory olfactory bulb would impair the ______ effect. A) Coolidge B) Whitley C) Ralph D) Vandenbergh E) pheromone Answer: D 62) Exposure to odors in human underarm sweat has been shown to A) induce the release of corticosterone from the adrenal glands. B) synchronize menstrual cycles in women. C) influence men's attractiveness to women. D) enhance sexual activity in men, but not women. E) delay the onset of puberty. Answer: B 63) Which of the following is true of pheromone action in humans? A) Menstrual cycles are delayed by exposure to human sweat. B) Men and women show decreased sexual behavior after exposure to pheromones. C) A T-shirt worn by a woman during her fertile phase is rated more positively by men than a T-shirt worn during her non-fertile phase. D) Women are attracted to the underarm sweat from men. E) Men are attracted to the underarm sweat from women. Answer: C Rationale: A T-shirt worn by a woman during her fertile phase is rated more positively by men than a T-shirt worn during her non-fertile phase. 64) A key difference between rodent and human female sexual behavior is that A) rats mate during diestrus as a form of birth control. B) the rat estrous cycle is longer than the human menstrual cycle. C) rats are capable of mating at any point during the estrous cycle. D) a female rat can only mate during estrus. E) a human female requires a progesterone surge for sexual receptivity. Answer: D Rationale: A key difference between rodent and human female sexual behavior is that a female rat can only mate during estrus. 65) A human female is more likely to initiate sexual activity with her partner A) when her estradiol levels are lowest. B) just prior to menstruation. C) in the winter months. D) just after a surge in testosterone from the adrenals. E) at a point in the menstrual cycle when her estradiol levels are highest. Answer: E 66) Which statement best describes the effects of a chemical castration (using a GnRH antagonist) on sexual behavior in a human male? A) increased secretion of testosterone B) decrease in sexual interest and intercourse after two weeks of treatment C) loss of erections during REM sleep, but no change in sex drive D) no change in sexual activity, because the adrenals also secrete testosterone E) a loss of tactile sensitivity Answer: B Rationale: Chemical castration (using a GnRH antagonist) given to a human male would be expected to decrease sexual interest and intercourse after two weeks of treatment. 67) Which of the following is a factor that can blunt the reduced sex drive observed in males who have experienced reduced plasma testosterone levels? A) substitution of estrogens for testosterone B) prior sexual experience C) the availability of Viagra, Levitra, and Cialis D) age E) prenatal exposure to estradiol Answer: B Rationale: Prior sexual experience is a factor that can blunt the reduced sex drive observed in males who have experienced reduced plasma testosterone levels. 68) Anticipation of sexual activity has the effect of A) reducing sexual motivation. B) reducing beard growth. C) raising plasma prolactin levels in human males. D) raising plasma testosterone levels in human males. E) reducing plasma testosterone levels in human males. Answer: D 69) Studies of the causes of homosexuality indicate that the best predictor of adult homosexuality is A) a history of birth complications. B) prolonged exposure to heavy metals in utero. C) the self-report of homosexual feelings. D) being raised by a harsh, punitive father. E) being raised by a warm, loving mother. Answer: C 70) Which of the following is true as to the biological basis of homosexuality? A) There are size differences in several brain regions that correlate with sexual orientation. B) The concordance rate for sexual orientation is low in male and in female identical twins. C) Maternal stress during pregnancy decreases androgen production in male rats, causing decreased male and increased female sexual behaviors. D) Testosterone has diminished activational effects in homosexual men compared to heterosexual men. E) There is no solid data linking brain structure differences with sexual orientation. Answer: E Rationale: There is no solid data linking brain structure differences with sexual orientation. 71) Which of the following are most likely to show preferences for masculine toys and an increased rate of homosexuality/bisexuality? A) women with congenital adrenal hyperplasia B) men with an XYY chromosomal type C) men born during the late winter months to stressed mothers D) men with congenital adrenal hyperplasia E) women with Turner's syndrome Answer: A 72) An individual with androgen insensitivity syndrome will A) not be feminized at puberty. B) be raised as a female. C) not function sexually as an adult. D) prefer a female sexual partner. E) show very masculine toy preferences. Answer: B 73) Twin studies indicate that A) there is a genetic basis for homosexuality in males as well as in females. B) early family environment is more important than genes for the development of homosexuality. C) a male child whose older twin sisters are heterosexual is more likely to be homosexual. D) homosexual women are likely to have homosexual male relatives. E) identical male twins are less likely to be concordant for homosexuality than are fraternal male twins. Answer: A 74) What principle is demonstrated by the findings that stimulation of the genitals elicits sex-related behaviors in a male animal whose spinal cord has been cut? A) Male sexual behavior can at times appear to be brainless. B) The brain is not required for the sexual reflexes of erection and ejaculation. C) Sexual orientation is dependent on spinal mechanisms. D) Pathways from the hypothalamus to the spinal cord are key to sexual behavior. E) Sexual reflexes cannot occur without the brain. Answer: B Rationale: The findings that stimulation of the genitals elicits sex-related behaviors in a male animal whose spinal cord has been cut suggests that the brain is not required for the sexual reflexes of erection and ejaculation. 75) The control of erection and ejaculation involves A) inhibition of the medial preoptic area. B) spinal cord circuits. C) circuits of neurons within the prefrontal area. D) circuits that interconnect the left and right hemispheres. E) cells that project from the vomeronasal organ to the medulla. Answer: B 76) The ________ plays an essential role in male sexual behavior. A) central nucleus of the amygdala B) periaqueductal gray matter C) medial preoptic area D) rostral medulla E) sexually dimorphic nucleus of the supraoptic area Answer: C 77) Electrical stimulation of the ________ elicits copulatory behavior in the ________. A) medial preoptic area; female rat B) central nucleus of the amygdala; female rat C) ventromedial nucleus; male rat D) medial preoptic area; male rat E) spinal cord; female rat Answer: D 78) Sexual behavior in a castrated male rat is restored by infusion of ________ into the ________. A) glutamate; spinal cord B) apomorphine; medial amygdala C) dopamine antagonists; medial preoptic area D) opiates; spinal cord E) testosterone; medial preoptic area Answer: E Rationale: Sexual behavior in a castrated male rat is restored by infusion of testosterone into the medial preoptic area. 79) The ________ directly inhibits the spinal motor neurons that control male copulatory movements. A) ventromedial hypothalamus B) rostral hypothalamus C) nucleus paragigantocellularis (nPGi) of the medulla D) medial amygdala E) medial preoptic area Answer: C 80) Serotonergic neurons that project from the ________ to the spinal cord may mediate the capacity of ________ to impair ejaculation in males. A) MPA; antipsychotics B) VMH; mood stabilizers C) MPA; amphetamine D) nPGi; SSRIs E) nPGi; mood stabilizers Answer: D 81) Drugs that act as ______ can impair ______ in males. A) serotonin agonists; erection B) antianxiety agents; erection C) serotonin antagonists; erection and ejaculation D) serotonin agonists; ejaculation E) dopamine agonists; ejaculation Answer: D 82) Imaging studies of the male brain during ejaculation indicate _______ activity within the _______. A) decreased; cerebellum B) increased; ventral tegmental area C) decreased; ventral tegmental area D) increased; amygdala E) increased; cerebellum Answer: B 83) Female sexual behavior is activated by A) glutamate infusion into the pons. B) electrical stimulation of the ventromedial hypothalamus. C) damage to the ventromedial hypothalamus. D) damage to the medial preoptic area. E) chemical stimulation of the medial preoptic area. Answer: B 84) Imaging studies suggest that pleasure that accompanies an orgasm in males and females may result from activation of the A) medial preoptic area. B) ventral tegmental area. C) spinal cord. D) lateral putamen. E) ventromedial hypothalamus. Answer: D 85) Female sexual behavior is suppressed by A) glutamate infusion into the pons. B) electrical stimulation of the ventromedial hypothalamus. C) damage to the ventromedial hypothalamus. D) damage to the medial preoptic area. E) chemical stimulation of the medial preoptic area. Answer: C 86) The correct sequence of neural pathways that control the muscles responsible for lordosis in female rats is A) medial amygdala → medial preoptic area → PAG → ventral horn of the spinal cord B) VMH → PAG → nPGi → ventral horn of the spinal cord C) VMH → nucleus accumbens → dorsal horn of the spinal cord D) medial amygdala → medial preoptic area → PAG → nucleus ambiguous E) VMH → PAG → medullary reticular formation → SNB Answer: B 87) The capacity of some human couples to pair bond may reflect the activity of A) oxytocin and dopamine. B) glutamate and glycine. C) dopamine and vasopressin. D) vasopressin and oxytocin. E) acetylcholine and norepinephrine. Answer: D 88) Which of the following is a benefit associated with the action of a lactating mother licking the anogenital region of her offspring? A) The pups develop a strong bond with the mother. B) The pups void urine from their bladders. C) Pup milk is recycled to form urine. D) This stimulation speeds up the onset of puberty in the pups. E)This stimulation bonds the mother with her pups. Answer: B Rationale: A benefit associated with the action of a lactating mother licking the anogenital region of her offspring is that this action voids urine from the pup’s bladders. 89) Disconnection of the ________ from the ________ abolishes maternal behavior. A) reticular formation; ventral tegmental area B) stria terminalis; ventral tegmentum C) medial preoptic area; brain stem D) ventromedial hypothalamus; spinal cord E) medial amygdala; lateral hypothalamus Answer: C 9.2 True-False 1) An ovary is an example of a gamete. Answer: False 2) Sexually dimorphic behavior differs between males and females. Answer: True 3) Activational effects of hormones occur in adulthood, after development is complete. Answer: True 4) The precursor of the internal male sex organs is called the Wolffian system. Answer: True 5) Androgens exert a defeminizing effect on the developing human. Answer: False 6) No hormone is required to create a female. Answer: True 7) Growth of axillary (underarm) and pubic hair in females is stimulated by estradiol. Answer: False 8) Estradiol is secreted by a maturing ovarian follicle. Answer: True 9) Repeated sexual encounters with the same female rat will lead to long pauses in male sexual behavior. Answer: True 10) Pheromones are chemical messages transmitted from one animal to another. Answer: True 11) The existence of a human sex pheromone has not been firmly established. Answer: True 12) The ability of a human female to mate is controlled by the ovarian hormones estradiol and progesterone. Answer: False 13) A primary cause of human homosexuality is strict parental discipline. Answer: False 14) Heredity does not contribute to human sexual orientation. Answer: False 15) Transection of the spinal cord abolishes male sexual reflexes. Answer: False 16) The medial preoptic area is a primary brain region involved in male sexual behavior. Answer: True 17) The ventral tegmental area is activated during orgasm in a human male. Answer: True 18) Parturition refers to the delivery of offspring. Answer: True 19) The case of Bruce/Brenda/David turned out well, with his successful marriage and career. Answer: False 9.3 Short-Answer Essay 1) Explain the differences between activational and organizational effects of hormones. Answer: Hormones exert effects through interactions with receptors. In some instances, those receptors modulate an ongoing behavior or initiate a cyclic event, typically in an adult organism (activational effect). Organizational effects tend to be permanent and are often noted in the developing organism. 2) Define the term bisexual and describe its relevance to early prenatal development. Answer: Bisexual in this instance refers to tissues that contain the precursors for both male and female sex organs. These tissues will develop into a female pattern in the absence of androgen during the prenatal period. 3) Describe and explain the differences between masculinization and defeminization. Give an example for each effect. Answer: Masculinization refers to the development of the Wolffian system—the male internal reproductive structures. These include the epididymis, the vas deferens, and the seminal vesicles. Defeminization refers to the inhibition of the Müllerian system—the precursors of the female reproductive system (the fimbriae, the Fallopian tubes, and the inner 2/3 of the vagina). 4) Defend the proposition that "Nature's impulse is to create a female." Answer: The internal and external genitalia will develop into a female form in the absence of any hormone stimulation. In order to develop the external male genitals, dihydrotestosterone must be present. Because both male and female precursor tissues exist for the internal reproductive structures, the female system (Müllerian) must be inhibited by anti-Müllerian hormone, and the male Wolffian system must be stimulated by the presence of androgens. 5) Differentiate between primary and secondary sex characteristics. Answer: The primary sex characteristics include the gonads, and the internal/external reproductive structures which are formed during the prenatal period. In contrast, the secondary sex characteristics develop in response to hormone stimulation during puberty. For a male, these include a beard and a deep voice, while for a female these would include development of breasts and wide hips. 6) Provide an overview of the hormonal events that form the human menstrual cycle (include in your answer a diagram showing hormone fluctuations across time). Answer: The anterior pituitary starts the cycle by the secretion of FSH, which acts on the ovarian follicles to secrete estradiol into the bloodstream. Increasing estradiol levels act on the anterior pituitary to produce a surge of luteinizing hormone (LH), which causes a follicle to rupture, thereby releasing the ovum. The ruptured follicle (corpus luteum) secretes estradiol and progesterone, which prepare the uterine lining for implantation of the ovum (if fertilized). If no implantation occurs, then estradiol/progesterone secretion stops, and the uterine lining is shed, thus resulting in blood flow (menstruation). 7) Explain why it is thought that pheromones play an important role in modulating the rodent estrous cycle. Answer: The rodent estrous cycle is four days in length and involves the secretion of estradiol followed by progesterone. Exposure of a female mouse to the odor of other female mice can slow their estrous cycles (Lee-Boot effect), while exposure to a male mouse can restart the cycle (Whitten effect). Moreover, the urine from a male mouse can speed up the onset of puberty (Vandenbergh effect) or can cause a pregnant female to abort a fetus fathered by another male mouse (Bruce effect). These effects require an intact vomeronasal system. 8) Describe the circuits that govern rodent female sexual behavior. Answer: The ventromedial hypothalamus receives input from the vomeronasal organ in the female rat and this key structure sends outputs to the PAG. Damage to the VMH or to the PAG will disrupt lordosis. 9) Describe the behaviors that comprise maternal behavior. Answer: At birth, the mother will clean, urge, and nurse her young. She will also build a nest to house them, and will retrieve them if they move out of the nest. Mothers are also capable of aggression to defend their young. 9.4 Essay 1) Describe the events that transpired for the case of David and explain how his case has been used to understand the relative contribution of socialization versus biology to sexual identity. Answer: At 7 months of age, his penis was accidentally removed during a botched circumcision procedure. He was reassigned as a female (Brenda) and underwent a sex change operation (removal of the testes and creation of a vagina). For some time it was thought that he shifted his identity to that of a female, suggesting that social forces are more powerful than are biological. However, after a stormy adolescent period in which she grew to believe that she was a boy, it was revealed to Brenda that she had been born a boy, and the procedure was reversed (mastectomy, creation of a phallus). One view is that David's brain was exposed to circulating levels of androgens, which masculinized his brain, and that socialization could not overcome the impact of androgenization on brain circuitry. 2) Compare and contrast the hormonal basis for sexual maturity in a male and in a female. Answer: Sexual maturity starts at puberty, when the hypothalamus secretes releasing hormones that act on the pituitary to secrete gonadotrophins from the anterior pituitary. The same 2 hormones are released in the male and in the female: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones induce the gonads (testes in the male; ovaries in the female) to secrete steroid hormones. For a female, this would be estradiol, and for a male this would be androgens. Estradiol elicits the secondary sex characteristics of the female (breast development, uterine lining growth, maturation of the genitals), while androgens stimulate genital and muscle growth in the male (and lower his voice). Adrenal androgens stimulate auxiliary and pubic hair growth. 3) Provide two types of evidence to support the proposition that there is a biological basis for homosexuality. Answer: Twin studies provide powerful evidence for a biological basis for homosexuality, with identical twins showing higher concordance values than do fraternal twins; this effect is noted for female homosexuals as well. A second line of evidence is that androgenization may play a role in that women with congenital adrenal hyperplasia show increased rates of homosexuality/bisexuality. 4) Compare the neural circuits that control male and female sexual behavior. Answer: The medial preoptic area is important for male sexual behavior (approach, intromission, and ejaculation). Electrical stimulation of the MPA elicits sexual behavior, whereas damage to the MPA impairs male sexual behavior. The MPA receives input from the vomeronasal organ and projects to spinal cord motor neurons that control copulation. In contrast, the ventromedial hypothalamus receives input from the vomeronasal organ in the female rat, and this key structure sends outputs to the PAG. Damage to the VMH or to the PAG will disrupt lordosis. Test Bank for Foundations of Behavioral Neuroscience Neil R. Carlson 9780205968091, 9780134639796, 9780205947997
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