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1) What do budding and fragmentation have in common? A) Both are types of asexual reproduction. B) Both produce large numbers of offspring. C) Both occur in sea stars. D) Both involve meiosis. E) A and B only |
A) Both are types of asexual reproduction. |
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2) Asexual reproduction in animals might involve A) fission and budding. B) fragmentation and mitosis. C) regeneration. D) A and B only E) A, B, and C |
E) A, B, and C |
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3) Which of the following are possible advantages of asexual reproduction? A) It allows the species to endure periods of fluctuating or unstable environmental conditions. B) It enhances genetic variability in the species. C) It enables the species to colonize new regions rapidly. D) Both A and B are true. E) A, B, and C are true. |
C) It enables the species to colonize new regions rapidly. |
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4) Why do genetic mutations in asexually reproducing organisms lead to more evolutionary change than do genetic mutations in sexually reproducing ones? A) The haploid mutations of asexually reproducing organisms are passed to all of their offspring. B) Asexually reproducing organisms devote more time and energy to the process of reproduction. C) Sexually reproducing organisms can produce more offspring in a given time. D) More genetic variation is present in organisms that reproduce asexually. E) Asexually reproducing organisms have more dominant genes than organisms that reproduce sexually. |
A) The haploid mutations of asexually reproducing organisms are passed to all of their offspring. |
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5) What are the advantages of asexual reproduction? A) It promotes genetic stability. B) It enhances the survival rates of parents. C) The limited number of offspring prevents overpopulation. D) It promotes geographic distribution of species. E) It allows animals to replace lost appendages. |
A) It promotes genetic stability. |
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6) Which of the following is a form of sexual reproduction? A) fragmentation B) budding C) hermaphroditism D) parthenogenesis E) fission |
C) hermaphroditism |
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7) You observe an organism with the following characteristics: parthenogenetic reproduction, internal development of embryos, presence of an amnion, lack of parental care of young. Of the following, the organism is probably a(n) A) earthworm. B) lizard. C) bird. D) frog. E) mammal. |
B) lizard. |
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8) Why is sexual reproduction important? A) It allows animals to conserve resources and reproduce only during optimal conditions. B) The resulting diverse phenotypes may enhance survival of a population in a changing environment. C) It can result in numerous offspring in a short amount of time. D) It enables isolated animals to colonize a habitat rapidly. E) Both A and D are important. |
B) The resulting diverse phenotypes may enhance survival of a population in a changing environment. |
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9) Which of the following is not required for internal fertilization? A) copulatory organ B) sperm receptacle C) behavioral interaction D) internal development of the embryo E) All of the above are necessary for internal fertilization. |
D) internal development of the embryo |
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10) What advantage does internal fertilization have compared with external fertilization? A) Usually many offspring are produced, ensuring survival of the species. B) The time and energy devoted to reproduction is decreased. C) The smaller number of offspring often receive a greater amount of parental protection. D) The increased survival rate results in rapid population increases. E) Usually a smaller number of genes are present, which promotes genetic stability. |
C) The smaller number of offspring often receive a greater amount of parental protection. |
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11) Internal and external fertilization both A) produce a zygote. B) occur in vertebrates. C) occur only in terrestrial animals. D) A and B only E) A and C only |
D) A and B only |
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12) Organisms that produce amniote eggs, in general, A) have a higher embryo mortality rate than do those with unprotected embryos. B) invest most of their reproductive energy in the embryonic and early postnatal development of their offspring. C) invest more energy in parenting than do placental animals. D) produce more gametes than do those animals with external fertilization and development. E) All of the above are correct. |
B) invest most of their reproductive energy in the embryonic and early postnatal development of their offspring. |
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13) Which statement about reproduction in invertebrates is incorrect? A) Many invertebrates have separate sexes. B) Many invertebrates utilize external fertilization. C) A few species split open to release gametes to the environment. D) Some invertebrates have structures that store sperm. E) Invertebrates do not engage in internal fertilization. |
E) Invertebrates do not engage in internal fertilization. |
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14) A cloaca is an anatomical structure found in many nonmammalian vertebrates, which functions as A) a specialized sperm-transfer device produced by males. B) a common exit for the digestive, excretory, and reproductive systems. C) a region bordered by the labia minora and clitoris in females. D) a source of nutrients for developing sperm in the testes. E) a gland that secretes mucus to lubricate the vaginal opening. |
B) a common exit for the digestive, excretory, and reproductive systems. |
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15) Which of the following produce testosterone? A) sperm cells B) hypothalamus C) Leydig cells D) anterior pituitary E) seminiferous tubules |
C) Leydig cells |
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16) After sperm cells are produced, they are mainly stored in the A) urethra. B) prostate. C) epididymis. D) seminal vesicles. E) bulbourethral gland. |
C) epididymis. |
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17) In men, the excretory and reproductive systems share which structure? A) vas deferens B) urinary bladder C) seminal vesicle D) urethra E) ureter |
D) urethra |
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18) Which of these does not contribute to the fluids that make up human semen? A) bulbourethral glands B) vas deferens C) prostate gland D) seminal vesicles E) both A and B |
B) vas deferens |
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19) Where are human sperm cells produced? A) prostate gland B) vas deferens C) the seminiferous tubules of the testes D) epididymis E) Sertoli cells |
C) the seminiferous tubules of the testes |
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20) What effect would surgical removal of the seminal vesicles have on the human male reproductive system? A) It would cause sterility because sperm would not be produced. B) It would cause sterility because sperm would not be able to exit the C) The failure rate for the withdrawal method of birth control would go down. D) There would be a minimal loss in semen volume. E) Semen would not contain energy-providing nutrients for the sperm. |
E) Semen would not contain energy-providing nutrients for the sperm. |
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21) What comprises the fluid part of human semen? A) androgens such as testosterone B) sperm and secretions from the prostate and bulbourethral glands C) sperm and secretions from the prostate gland, bulbourethral glands, and seminal vesicles D) sperm and prostaglandins E) sperm and anticoagulant enzymes |
C) sperm and secretions from the prostate gland, bulbourethral glands, and seminal vesicles |
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22) In humans, the egg is released from the ovary and enters the oviduct. How is this accomplished? A) The force of the follicular ejection propels the egg into the oviduct. B) The egg is drawn into the oviduct by the action of beating cilia located in the opening of the oviduct. C) The egg moves through a small tube that connects the ovary and the oviduct. D) The egg propels itself into the oviduct by the beating action of its flagellum. E) Peristalsis of ovarian muscles moves the egg into the oviduct. |
B) The egg is drawn into the oviduct by the action of beating cilia located in the opening of the oviduct. |
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23) What is the narrow opening of the human uterus called? A) vagina B) cervix C) oviduct D) fallopian tube E) vas deferens |
B) cervix |
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24) Which of the following male and female structures consist largely of erectile tissue richly supplied with nerve endings? A) penis and clitoris B) vas deferens and oviduct C) testes and ovaries D) seminiferous tubules and vagina E) prostate and ovaries |
A) penis and clitoris |
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25) During the human sexual response, vasocongestion A) occurs in the clitoris, vagina, and penis. B) occurs in the testes. C) can cause vaginal lubrication. D) A and B only E) A, B, and C |
E) A, B, and C |
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26) During sexual arousal, myotonia is to nipple as A) orgasm is to resolution. B) excitement is to plateau. C) estrogen is to the mammary D) vasocongestion is to the penis. E) labia minora is to labia majora. |
D) vasocongestion is to the penis. |
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27) The diploid chromosome number for humans is 46. How many chromatids will there be in a secondary spermatocyte? A) 23 B) 46 C) 69 D) 92 E) 184 |
B) 46 |
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28) Which cells are diploid? A) spermatids B) spermatogonia C) mature sperm cells D) A and B only E) A, B, and C |
B) spermatogonia |
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29) Which of these statements is true about human sperm cells? A) They are rich in nutrient material. B) They are liberated from the corpus luteum. C) They are less numerous than ova. D) They are highly motile. E) They have 46 chromosomes. |
D) They are highly motile. |
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30) In vertebrate animals, spermatogenesis and oogenesis differ, in that A) oogenesis begins at the onset of sexual maturity. B) oogenesis produces four haploid cells, whereas spermatogenesis produces only one functional spermatozoon. C) oogenesis produces one functional ovum, whereas spermatogenesis produces four functional spermatozoa. D) spermatogenesis begins before birth. E) spermatogenesis is not complete until fertilization occurs. |
C) oogenesis produces one functional ovum, whereas spermatogenesis produces four functional spermatozoa. |
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31) In which of the following ways are mature human sperm and ova similar? A) They both have the same number B) They are approximately the same size. C) They each have a flagellum that provides motility. D) They are produced from puberty until death. E) They are formed before birth. |
A) They both have the same number of chromosomes. |
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32) Which of the following statements about gametogenesis is incorrect? A) Spermatogenesis continues throughout the male’s life; oogenesis stops at menopause. B) Oogenesis results in one ovum, while spermatogenesis results in millions of sperm. C) Spermatogenesis is a continuous, uninterrupted process; oogenesis undergoes long "resting" periods. D) The process of oogenesis is completed when the egg cell is penetrated by sperm. E) The primary spermatocyte is a haploid cell. |
E) The primary spermatocyte is a haploid cell. |
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33) Which of these is a male primary sex characteristic? A) deepening of the voice B) facial and pubic hair C) increased muscle growth D) development of external reproductive structures E) both B and D |
D) development of external reproductive structures |
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34) Which of these is a male secondary sex characteristic? A) development of external reproductive structures B) development of vasa deferentia and other ducts C) sperm production D) increased muscle growth E) B and C only |
D) increased muscle growth |
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35) How do the estrous and menstrual cycles compare? A) Endometrial bleeding occurs during the menstrual cycle; the endometrium is reabsorbed by the uterus during the estrous cycle. B) There are more pronounced behavioral changes during menstrual cycles than during estrous cycles. C) There are stronger effects of season and climate on menstrual cycles. D) Copulation can only occur during the period surrounding ovulation in both the estrous and menstrual cycles. E) The length of both cycles averages 28 days. |
A) Endometrial bleeding occurs during the menstrual cycle; the endometrium is reabsorbed by the uterus during the estrous cycle. |
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36) What is the breakdown and discharge of the soft uterine tissues that occurs if no egg is fertilized? A) menstruation B) lactation C) fertilization D) menopause E) ovulation |
A) menstruation |
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37) Which of these best describes the menstrual cycle? A) It refers specifically to changes that occur in the endometrium of the uterus. B) The cycle length is 28 days and varies little from one woman to another. C) It continues from puberty until death. D) It begins with the follicular phase. E) It is primarily regulated by follicle-stimulating hormone (FSH). |
A) It refers specifically to changes that occur in the endometrium of the uterus. |
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38) The secretory phase of the menstrual cycle A) is associated with dropping levels of estrogen and progesterone. B) starts when the endometrium begins to degenerate. C) corresponds with the luteal phase of the ovarian cycle. D) corresponds with the follicular phase of the ovarian cycle. E) is the beginning of the menstrual flow. |
C) corresponds with the luteal phase of the ovarian cycle. |
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39) What are the three phases of the ovarian cycle? A) menstrual, ovulation, and luteal B) follicular, luteal, and secretory C) menstrual, proliferative, and secretory D) follicular, ovulation, and luteal E) proliferative, luteal, and ovulation |
D) follicular, ovulation, and luteal |
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40) There are five hormones regulating the human menstrual and ovarian cycles. Which of these structures secrete(s) these hormones? A) hypothalamus B) pancreas C) ovaries D) A and C only E) A, B, and C |
D) A and C only |
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41) Inhibition of the release of GnRH from the hypothalamus will A) stimulate production of estrogen and progesterone. B) initiate ovulation. C) inhibit secretion of gonadotropins D) stimulate secretion of LH and FSH. E) initiate the flow phase of the menstrual cycle. |
C) inhibit secretion of gonadotropins from the pituitary. |
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42) If the release of LH were inhibited in a human female, which of the following events would not occur? A) release of FSH from the pituitary B) maturation of a primary follicle and oocyte C) ovulation of a secondary oocyte D) release of GnRH from the hypothalamus E) production of estrogen by follicle cells |
C) ovulation of a secondary oocyte |
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43) Which structure is not correctly paired with its function? A) seminiferous tubules-add fluid containing mucus, fructose, and prostaglandin to semen B) scrotum-encases testes and holds them below the abdominal cavity C) epididymis-stores sperm D) prostate gland-adds alkaline secretions to semen E) ovary-secretes estrogen and progesterone |
A) seminiferous tubules-add fluid containing mucus, fructose, and prostaglandin to semen |
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44) One function of the corpus luteum is to A) nourish and protect the egg cell. B) produce prolactin in the alveoli. C) produce progesterone and estrogen. D) convert into a hormone-producing follicle after ovulation. E) stimulate ovulation. |
C) produce progesterone and estrogen. |
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45) During the menstrual cycle, what is the main source of progesterone in females? A) adrenal cortex B) anterior pituitary C) corpus luteum D) developing follicle E) placenta |
C) corpus luteum |
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46) hormone that triggers ovulation |
A) LH |
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47) hormone secreted by the growing follicle |
E) estrogen |
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48) stimulates the corpus luteum in females |
A) LH |
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49) hypothalamic hormone that stimulates the secretion of gonadotropins by the anterior pituitary |
D) GnRH |
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the anterior pituitary hormone that stimulates the maturation of the follicle in the ovary during the beginning of the menstrual cycle |
B) FSH |
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51) Which of the following hormones is incorrectly paired with its action? A) GnRH-controls release of FSH and LH B) estrogen-responsible for primary and secondary female sex characteristics C) human chorionic gonadotropin-maintains secretions from the corpus luteum D) luteinizing hormone-stimulates ovulation E) progesterone-stimulates follicles to develop |
E) progesterone-stimulates follicles to develop |
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52) The hormone progesterone is produced A) by the pituitary and acts directly on the ovary. B) in the ovary and acts directly on the testes. C) in the ovary and acts directly on the uterus. D) in the pituitary and acts directly on the uterus. E) in the uterus and acts directly on the pituitary. |
C) in the ovary and acts directly on the uterus. |
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53) What happens if the hormone progesterone is not secreted in a human female? A) Secondary sex characteristics do not develop. B) The pituitary is stimulated to secrete gonadotropins. C) Uterine contractions begin stimulating childbirth. D) Enlargement of arteries supplying blood to the endometrium and growth of endometrial glands do not occur properly. E) The ovary begins to form the corpus luteum. |
D) Enlargement of arteries supplying blood to the endometrium and growth of endometrial glands do not occur properly. |
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54) What causes menopause? A) The follicle supply is exhausted. B) A decline in production of estrogens by the ovaries. C) Temperature increases inhibit ova maturation. D) There is a lack of adequate blood supply to the ovaries. E) Progesterone blocks the ovarian cycle. |
B) A decline in production of estrogens by the ovaries. |
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55) For normal human fertilization to occur, A) many ova must be released. B) the uterus must be enlarged. C) only one sperm must penetrate the egg. D) secretion of pituitary FSH and LH must decrease. E) the secondary oocyte must implant in the uterus. |
C) only one sperm must penetrate the egg. |
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56) Fertilization of human eggs usually takes place in the A) ovary. B) uterus. C) vagina. D) oviduct. E) labia minora. |
D) oviduct. |
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57) Which of the following structures is incorrectly paired with its function? A) epididymis—maturation and storage of sperm B) oviduct—site of normal embryonic implantation C) seminal vesicles—add sugar and mucus to semen D) placenta—maternal and fetal exchange organ E) prostate gland—adds alkaline substances to semen |
B) oviduct—site of normal embryonic implantation |
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58) During human gestation, organogenesis occurs during the first trimester. What is the significance of this fact? A) It allows for early detection of genetic disorders. B) This may block progesterone production and thus cause a spontaneous abortion. C) It may stimulate infant cardiovascular problems. D) Radiation and drugs should be avoided, as the embryo is extremely sensitive to birth defects at this time. E) It may compress the mother’s abdominal organs, causing frequent urination and constipation. |
D) Radiation and drugs should be avoided, as the embryo is extremely sensitive to birth defects at this time. |
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embryonic hormone that maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy |
D) human chorionic gonadotropin (HCG) |
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triggers ovulation of the secondary oocyte |
A) luteinizing hormone (LH) |
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61) hormone produced by the corpus luteum when stimulated by LH |
C) progesterone |
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62) hypothalamic hormone that triggers the secretion of FSH |
E) gonadotropin-releasing hormone (GnRH) |
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63) Which substance, when found in urine, indicates pregnancy? A) progesterone B) estrogen C) follicle-stimulating hormone D) human chorionic gonadotropin E) hypothalamus releasing factors |
D) human chorionic gonadotropin |
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secreted by the Leydig cells of the testes |
B) testosterone |
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65) participates in the regulation of labor contractions |
C) oxytocin |
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66) initiates the growth of the placenta and enlargement of the uterus |
E) progesterone |
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67) high concentration of this hormone inhibits secretion of LH from the pituitary |
E) progesterone |
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68) required so that the corpus luteum can function through the first and part of the second trimesters of pregnancy |
A) human chorionic gonadotropin |
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69) What would happen if a woman in the later stages of pregnancy were given a combination of estrogen and oxytocin? A) Oxytocin receptors would develop on uterine smooth muscle cells. B) Prostaglandins would be secreted from the placenta. C) Contractions of uterine muscles would begin. D) A and C only E) A, B, and C |
E) A, B, and C |
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70) Which of these is not a correct statement about human reproduction? A) The ability of a pregnant woman not to reject her "foreign" fetus may be due to the suppression of the immune response in her uterus. B) By the eighth week, organogenesis is complete and the embryo is referred to as a fetus. C) Lactation is the production and release of milk from the mammary glands. D) Parturition begins with conception and ends with gestation. E) Puberty is the onset of reproductive ability. |
D) Parturition begins with conception and ends with gestation. |
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71) Which of the following birth control methods is least effective? A) diaphragm B) condom C) coitus interruptus D) vasectomy E) rhythm method |
C) coitus interruptus |
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72) birth control pill |
A. prevents release of mature eggs from the ovaries |
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73) intrauterine device |
C. prevents implantation of an embryo |
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74) tubal ligation |
E. prevents oocytes from traveling into the uterus |
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75) vasectomy |
D. prevents sperm from entering the urethra |
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76) diaphragm |
B. prevents fertilization by keeping sperm and egg physically separated by a barrier |
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77) How do different contraceptive methods work? A) prevent the release of sperm and eggs B) keep sperm and eggs separated C) prevent implantation of an embryo D) A and B only E) A, B, and C |
E) A, B, and C |
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78) Which of these statements explains the primary mechanism by which birth control pills work? A) They stop the release of GnRH, FSH, and LH. B) They cause a woman’s cervical mucus to change and block sperm from entering the uterus. C) They cause spontaneous abortions. D) They block progesterone, thus pregnancy cannot be maintained. E) They prevent uterine implantation by irritating the endometrium. |
A) They stop the release of GnRH, FSH, and LH. |
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79) The drug RU486 functions by A) inhibiting release of gonadotropins from the pituitary. B) blocking progesterone receptors in the uterus. C) preventing release of the secondary oocyte from the ovary. D) A and B E) A, B, and C |
B) blocking progesterone receptors in the uterus. |
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80) Human fertility drugs increase the chance of multiple births, probably because they |
B) stimulate follicle development. |
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81) Which pituitary secretion stimulates sperm production? |
E) FSH |
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82) Which hormone(s) is (are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth? |
A) androgens |
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83) Ovulation usually occurs on or about day ________ of a 28-day ovarian cycle. |
C) 14 |
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84) After ovulation, high levels of ________ inhibit ________ secretion. A) estrogen and progesterone; FSH and LH B) FSH and LH; estrogen and progesterone C) HCG; estrogen and progesterone D) estrogen; FSH E) androgens; FSH and LH |
A) estrogen and progesterone; FSH and LH |
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85) If there is no fertilization, degeneration of the corpus luteum results in a drop in ________, which results in the sloughing off of the uterus’s endometrium. A) FSH B) estrogen and progesterone C) hypothalamic secretion of D) HCG E) LH |
B) estrogen and progesterone |
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86) Which of the following characterizes parthenogenesis? |
D) An egg develops without being fertilized. |
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87) Which structure is incorrectly paired with its function? |
B) spermatheca-stores sperm in male honeybees |
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88) Which of the following male and female structures are least alike in function? |
A) seminiferous tubules-vagina |
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89) A difference between estrous and menstrual cycles is that A) nonmammalian vertebrates have estrous cycles, whereas mammals have menstrual cycles. B) the endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles. C) estrous cycles occur more often than menstrual cycles. D) estrous cycles are not controlled by hormones. E) ovulation occurs before the endometrium thickens in estrous cycles. |
B) the endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles. |
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90) Peaks of LH and FSH production occur during A) the flow phase of the menstrual (uterine) cycle. B) the beginning of the follicular phase of the ovarian cycle. C) the period just before ovulation. D) the end of the luteal phase of the ovarian cycle. E) the secretory phase of the menstrual cycle. |
C) the period just before ovulation. |
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91) In sequential hermaphroditism, |
A) some individuals may change from male to female. |
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92) During human gestation, rudiments of all organs develop |
A) in the first trimester. |
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93) Which pharmacological strategy is most likely to result in a successful male contraceptive? |
A) preventing the production of functionally normal sperm |
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94) Fertilization of human eggs most often takes place in the |
D) oviduct. |
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95) In male mammals, excretory and reproductive systems share |
B) the urethra. |
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Salamander and insect populations consisting only of genetically identical females lack males because _____. |
sperm do not fuse with eggs during reproduction, but the eggs develop into embryos anyway. [Parthenogenesis is a process in which the egg develops without being fertilized.] |
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The "reproductive handicap" for sexual reproduction refers to _____. |
have only half the offspring are females. [A female undergoing asexual reproduction would have offspring that have 100% of her genes, whereas a sexually reproducing female typically passes only 50% of her genetic material to her offspring.] |
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Animals utilizing external fertilization are typically _____. |
aquatic animals. |
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Humans form gametes by __. |
gametogenesis. |
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What role do germ cells play in gametogenesis? |
They produce cells that divide by mitosis and then undergo meiosis to form gametes. |
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What products are formed when a diploid cell undergoes meiosis? |
Four haploid cells. |
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Which of the following statements about oogenesis in humans is true? |
Beginning at puberty, a primary oocyte completes its first meiotic division to form a secondary oocyte and a polar body approximately every month. [This secondary oocyte is released into the oviduct during ovulation and then begins meiosis II, which is not complete unless the oocyte is fertilized by a sperm cell.] |
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Which diploid cells are produced by an embryonic germ cell? |
Spermatogonia. |
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Spermatogonia divide by__. |
mitosis and differentiate into primary spermatocytes. Starting at puberty, hormones stimulate the primary spermatocytes to undergo meiosis I to form secondary spermatocytes, which then undergo meiosis II to form spermatids. |
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How does spermatogenesis differ from oogenesis? |
Diploid cells give rise to four functional gametes in spermatogenesis. |
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Which of the following correctly traces the path of sperm from their site of production to their exit from a man’s body? |
seminiferous tubule → epididymis → vas deferens → urethra |
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A fertilized egg usually implants itself and develops in the _____. |
Uterus |
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A rapid increase in the _____ level stimulates ovulation. |
luteinizing hormone |
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After ovulation, high levels of _____ inhibit _____ secretion. |
estrogen and progesterone … FSH and LH |
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Developing ovarian follicles primarily secrete _____. |
estrogens |
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If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum. |
human chorionic gonadotropin |
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The corpus luteum secretes __ and __, which maintain the endometrium for implantation. |
estrogen…progesterone |
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If there is no fertilization, degeneration of the corpus luteum results in a drop in _____, which results in the sloughing off of the uterus’s endometrium. |
estrogen and progesterone |
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Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle. |
14 |
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What is the usual site of the fertilization of an egg cell? |
Oviduct |
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Sperm become capable of movement while in the _____. |
Epididymis |
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Sperm exit a male’s body via the _____. |
Urethra |
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The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____. |
negative … hypothalamus … pituitary gland |
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Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth? |
Androgens |
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Which pituitary secretion stimulates sperm production? |
FSH |
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Which pituitary secretion stimulates the testes to secrete androgens? |
LH |
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Sperm develop in the _____. |
seminiferous tubules |
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The anatomical location for the typical union of a sperm and an egg (conception) is the _____. |
Oviducts |
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The "information receiving" section of a neuron is its _____. |
dendrites |
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A simple nervous system |
includes sensory information, an integrating center, and effectors. |
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The nucleus and most of the organelles in a neuron are located in the |
cell body. |
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The point of connection between two communicating neurons is called the |
synapse |
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In a simple synapse, neurotransmitter chemicals are released by |
the presynaptic membrane. |
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The operation of the sodium-potassium "pump" moves |
sodium ions out of the cell and potassium ions into the cell. |
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ATP hydrolysis directly powers the movement of |
Na+ out of cells. |
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Two fundamental concepts about the ion channels of a "resting" neuron are that the channels |
open and close depending on stimuli, and are specific as to which ion can traverse them. |
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The "selectivity" of a particular ion channel refers to its |
permitting passage only to a specific ion. |
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In a neuron, during the depolarization phase that may trigger an action potential _____. |
some voltage-gated sodium channels are open |
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Select the choice that describes neurons with the fastest conduction velocity for action potentials. |
thick, myelinated neurons |
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For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron’s cytoplasm would result in the |
hyperpolarization of the neuron. |
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A toxin that binds specifically to voltage-gated sodium channels in axons would be expected to |
prevent the depolarization phase of the action potential. |
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The "undershoot" phase of after-hyperpolarization is due to |
sustained opening of voltage-gated potassium channels. |
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Immediately after an action potential passes along an axon, it is not possible to generate a second action potential; thus, we state that the membrane is briefly |
refractory |
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In the sequence of permeability changes for a complete action potential, the first of these events that occurs is the |
opening of voltage-gated sodium channels. |
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Saltatory conduction is a term applied to |
jumping from one node of Ranvier to the next in a myelinated neuron. |
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A nerve poison that blocks acetylcholine receptors on dendrites would _____. |
reduce the binding of acetylcholine to its receptors on the postsynpatic membrane. The binding of neurotransmitter molecules to their specific receptors on the postsynaptic membrane opens ion channels, which completes the transmission of the impulse to the receiving cell. A nerve poison that blocked the acetylcholine receptors would prevent reception of the signal. |
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The surface on a neuron that discharges the contents of synaptic vesicles is the |
presynaptic membrane. |
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Neurotransmitters are released from axon terminals via |
exocytosis |
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The following steps refer to various stages in transmission at a chemical synapse. |
3 → 2 → 5 → 1 → 4 |
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The activity of acetylcholine in a synapse is terminated by its |
degradation by a hydrolytic enzyme on the postsynaptic membrane |
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When several EPSPs arrive at the axon hillock from different dendritic locations, depolarizing the postsynaptic cell to threshold for an action potential, this is an example of |
spatial summation. |
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When several IPSPs arrive at the axon hillock rapidly in sequence from a single dendritic location, hyperpolarizing the postsynaptic cell more and more and thus preventing an action potential, this is an example of |
temporal summation. |
|
Neurotransmitters affect postsynaptic cells by |
-causing molecular changes in the cells. -altering the permeability of the cells. -affecting ion-channel proteins. -initiating signal transduction pathways in the cells. |
|
An amino acid that operates at inhibitory synapses in the brain is |
GABA |
|
Most of the synapses in vertebrates conduct information in only one direction |
because only the postsynaptic cells can bind and respond to neurotransmitters |
|
What happens when a resting neuron’s membrane depolarizes? |
The neuron’s membrane voltage becomes more positive. |
|
Identify the correct statement(s) about the resting membrane potential of a cell. |
-Potassium (K+) and sodium (Na+) gradients are maintained by active transport in a resting mammalian neuron. -Concentration gradients of potassium (K+) and sodium (Na+) across the plasma membrane represent potential energy. |
|
If the membrane potential of a neuron decreases, the membrane potential _____. |
becomes more positive. |
|
The plasma membrane of a neuron has voltage-gated sodium and potassium channels. What is the effect of membrane depolarization on these channels? |
Membrane depolarization first opens sodium channels and then opens potassium channels. |
|
What causes the falling phase of the action potential? Select the best answer. |
Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels |
|
The central nervous system is lacking in animals that have |
radial symmetry. |
|
Cephalization, the clustering of neurons and interneurons in the anterior part of the animal, is apparent in |
Planaria |
|
Choose the correct match of glial cell type and function. |
astrocytes-metabolize neurotransmitters and modulate synaptic effectiveness |
|
The cerebrospinal fluid is |
a filtrate of the blood. |
|
The blood-brain barrier |
is formed by tight junctions. |
|
Cerebrospinal fluid can be described as all of the following except |
formed from layers of connective tissue. |
|
Preparation for the fight-or-flight response includes activation of the ________ nervous system. |
sympathetic |
|
The divisions of the nervous system that have antagonistic, or opposing, actions are the |
sympathetic and parasympathetic systems. |
|
The activation of the parasympathetic branch of the autonomic nervous system is associated with |
resting and digesting. |
|
Dolphins can be awake and asleep at the same time because _____. |
one side of the brain can sleep while the other side maintains swimming and breathing behaviors |
|
Emotion, motivation, olfaction, behavior, and memory, in humans, are mediated by the _____. |
limbic system |
|
Increases and decreases of the heart rate result from changes in the activity of the |
medulla oblongata. |
|
The unconscious control of respiration and circulation is associated with the |
medulla oblongata. |
|
The suprachiasmatic nuclei are found in the |
hypothalamus |
|
As vertebrates evolved, the increasingly complex structure of the brain conferred increasingly complex function, especially apparent in the _____. |
cerebral complex, which is greatly expanded in nonhuman primates and cetacean |
|
Calculation, contemplation, and cognition are human activities associated with increased activity in the |
cerebrum |
|
Which of the following shows a brain structure correctly paired with one of its primary functions? |
frontal lobe-decision making |
|
Our understanding of mental illness has been most advanced by discoveries involving the |
chemicals involved in brain communications. |
|
An injury to the occipital lobe will likely impair the function of the |
primary visual cortex. |
|
he sense described as umami is one of _____ |
savory and delicious sensation on the tongue |
|
Injury to just the hypothalamus would most likely disrupt _________ |
regulation of body temperature |
|
Identify the correct statement(s) about glial cells and their functions. |
Astrocytes participate in the formation of the blood-brain barrier. |
|
Which of these observations illustrate the developmental plasticity of the human nervous system? |
-A person suffering from phantom limb pain following amputation may stop feeling pain after viewing a reflection of the remaining limb in a mirrored box. -When activity at a synapse correlates with the activity of other synapses, that synaptic connection is reinforced. |
|
Sexual reproduction includes a reproductive pattern called _____. |
hermaphroditism |
|
Animals utilizing external fertilization are typically ____ |
aquatic animals |
|
Which of the following correctly traces the path of sperm from their site of production to their exit from a man’s body? |
seminiferous tubule → epididymis → vas deferens → urethra |
|
In humans, oogenesis in comparison to spermatogenesis is different in that _____ |
oogenesis does not complete meiosis until after fertilization, but spermatogenesis is complete before the sperm leave the body |
|
The anatomical location for the typical union of a sperm and an egg (conception) is the ___ |
oviducts |
|
Among the following, the earliest consequence of the acrosomal reaction is ____ |
the membrane of the egg depolarizing |
|
The first stage of embryonic development is _____. This process produces _____. |
cleavage … a cluster of cells |
|
The mesoderm gives rise to ___ |
skeletal and muscular systems |
|
Choose the correct developmental sequence of animal development. |
fertilization → cleavage → gastrulation → organogenesis |
|
Salamander and insect populations consisting only of genetically identical females lack males because _____ |
sperm do not fuse with eggs during reproduction, but the eggs develop into embryos anyway |
|
The "reproductive handicap" for sexual reproduction refers to __ |
have only half the offspring are females |
|
Birds, reptiles, and mammals are called "amniotes" because _____. |
they have extra-embryonic membranes that develop an aqueous environment in which development occur |
|
Embryonic cells especially active in assuring nutritional exchange between a pregnant woman and her embryo are found in |
trophoblast |
|
An embryonic cell that is "totipotent" is one that can _____. |
by itself, give rise to the entire embryo, as cleavage proceeds |
|
Which of the following characterizes parthenogenesis? |
An egg develops without being fertilized. |
|
The cortical reaction of sea urchin eggs functions directly in |
the formation of a fertilization envelope |
|
Which of the following is not properly paired? |
seminiferous tubule–cervix |
|
Peaks of LH and FSH production occur during |
the period just before ovulation |
|
For which is the number the same in males and females? |
meiotic divisions required to produce each gamete |
|
Which statement about human reproduction is false? |
The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules. |
|
What is the fundamental difference between male and female vertebrates? |
Males produce many, motile gametes and females produce few, stationary gametes |
|
What is the "twofold" cost of sex? |
The higher number of female offspring produced by an asexual female |
|
Identify the role(s) of follicle-stimulating hormone (FSH) in human reproduction. |
-FSH stimulates the growth of new follicles in the ovary. -FSH promotes the activity of Sertoli cells, which nourish sperm developing within seminiferous tubules. |
|
The hormone epinephrine causes opposite effects in two populations of target cells because _____. |
each set of target cells has different receptor-transduction mechanisms |
|
In their mechanism of action, a difference between lipid-soluble and water-soluble hormones is that _____. |
lipid-soluble hormones bind to an intracellular receptor and this hormone-receptor complex binds to DNA |
|
Oxytocin secretion and milk release from the mammary glands of lactating female mammals are initiated by _____. |
the physical sensation of the baby sucking at the nipple |
|
Jet lag occurs when a person moves rapidly from one time zone to another, causing conflict between the body’s biological rhythm and the new cycle of light and dark. Some scientists suspect that jet lag may result from disruption of the daily cycle of secretion of the hormone known as _____. |
melatonin |
|
Hormones are _____. |
chemical signals between cells, transported in blood or hemolymph |
|
Vertebrates have two major communication and control systems: the endocrine system and the nervous system. Choose the correct statement describing the coordination of these systems. |
Epinephrine functions as a hormone in the endocrine system and as a neurotransmitter in the nervous system. |
|
Select the correct statement about feedback regulation in endocrine systems. |
Some homeostatic control systems rely on pairs of negatively regulated hormone pathways, each counterbalancing the other. |
|
Which hormone is placed into the correct chemical class? |
Calcitonin is a peptide hormone. |
|
The anterior and posterior lobes of the pituitary differ in that _____. |
many anterior pituitary hormones regulate other endocrine glands whereas posterior pituitary hormones regulate nonendocrine tissues |
|
How does the adrenal gland respond to stress? |
The adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress. |
|
Select the example that accurately illustrates this statement: "The endocrine and nervous systems act together to regulate an animal’s physiology." |
In response to stress, neurosecretory cells in the adrenal medulla release epinephrine and norepinephrine, which mediate various fight-or-flight responses. |
|
The figure shows how glucose homeostasis is maintained by two antagonistic hormones, insulin and glucagon. Select the correct statement about these hormones. |
Each of these hormones operates in a simple endocrine pathway. |
|
The closest algal relatives of land plants are _____. |
charophytes |
|
In seedless plants, a fertilized egg will develop into _____. |
sporophyte |
|
Which of the following traits was most important in enabling the first plants to move onto land? |
he development of sporopollenin to prevent the desiccation of zygotes |
|
The diploid generation of the plant life cycle always _____. |
produces spores |
|
Which of the following is a difference between plants and fungi? |
Fungi are heterotrophic, and plants are autotrophic. |
|
Seedless plants include _____. |
bryophytes, lycophytes, ferns, whisk ferns, and horsetails |
|
Most bryophytes, such as mosses, differ from all other plants in that they _____. |
lack true leaves and roots |
|
What evolutionary development allowed plants to grow tall? |
lignified vascular tissue |
|
During the Carboniferous period, forests consisting mainly of _____ produced vast quantities of organic matter, which was buried and later became coal. |
ferns and other seedless plants |
|
In contrast to bryophytes, in vascular plants the dominant stage of the life cycle is the _____. |
sporophyte |
|
When you look at a pine or maple tree, the plant you see is a _____. |
diploid sporophyte |
|
All seed plants _____. |
are heterosporous |
|
The adaptation that made possible the colonization of dry land environments by seed plants is most likely the result of the evolution of _____. |
pollen |
|
Gymnosperms were most abundant during the _____. |
Mesozoic |
|
In pine, the embryo develops within the _____. |
female gametophyte |
|
The major difference between angiosperms and gymnosperms comes from the _____. |
presence or absence of a protective covering over the ovule |
|
Angiosperms are different from all other plants because only they have _____. |
flowers |
|
Unlike most angiosperms, grasses are pollinated by wind. As a consequence, some unnecessary parts of grass flowers have almost disappeared. Which of the following parts would you expect to be most reduced in a grass flower? |
petals |
|
Human survival literally depends on the produce of _____. |
angiosperms |
|
Which of the following characteristics of plants is ABSENT in their closest relatives, the charophyte algae? |
alternation of generations |
|
A fruit is usually __________ |
a mature ovary |
|
Select the correct statement about charophytes, a taxon of green algae. |
Charophytes and land plants share four distinctive traits. |
|
Which of these facts provides the best support for the hypothesis that plants evolved from green algae? |
The chloroplasts of plants and green algae all have both chlorophyll a and b. |
|
Select the correct statement contrasting gametophytes and sporophytes. |
Sporophytes are diploid, whereas gametophytes are haploid. |
|
Select the correct statement about the life cycle of a fern. |
Plant gametophytes are haploid multicellular bodies. |
|
Select the correct statement describing the life cycle of angiosperms. |
Double fertilization in the life cycle of seed plants results in the production of a diploid zygote and a triploid endosperm nucleus. |
|
Which of these structures is a separate generation from the plant sporophyte? |
A male gametophyte within a pollen grai |
|
The "reproductive handicap" for sexual reproduction refers to _____. |
have only half the offspring are females |
|
Animals utilizing external fertilization are typically _____. |
aquatic animals |
|
Which of the following correctly traces the path of sperm from their site of production to their exit from a man’s body? |
seminiferous tubule → epididymis → vas deferens → urethra |
|
Which hormone’s secretion is controlled by a positive feedback mechanism? |
Oxytocin |
|
Suppose you wanted to start an animal-breeding business. For most of the following animals, you could start out with just a single animal. Which of the animals below would require that you start with at least two individuals? |
frogs |
|
Which of the following characterizes parthenogenesis? |
An egg develops without being fertilized. |
|
Which of the following is not properly paired? |
seminiferous tubule–cervix |
|
Which of the following is a true statement? |
The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles. |
|
Select the correct statement about reproduction and eukaryotic life cycles. |
Some animal adults are haploid. |
|
You observe a large black bird with a shiny black crest engaging in courtship behavior with a little brown bird. It would be reasonable to hypothesize that this is an example of _____. |
polygamy |
|
A female zebra finch reared by a father with a red feather taped to his head will select a mate with a similar ornament over an unornamented male. What are plausible ultimate explanations for this behavior (i.e., why it occurs in the context of natural selection)? |
A female zebra finch that chooses a mate that resembles her father is more likely to reproduce successfully. |
|
Sexual reproduction includes a reproductive pattern called _____. |
hermaphroditism |
|
At what stage of development does the brain essentially reach its adult size? |
middle childhood |
|
Due to proximity, adrenal glands are often damaged during surgery on what organ? |
kidney |
|
Which of the following do the adrenal glands depend on to release DHEA? |
pituitary 垂体 |
|
Your body doesn’t produce the correct amount of DHEA. Which of the following stages of development will be impacted? |
adrenarche |
|
Sperm become capable of movement while in the _____. |
epididymis |
|
Sperm exit a male’s body via the _____. |
urethra |
|
The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____. |
negative … hypothalamus … pituitary gland (An increase in androgens inhibits the secretion of releasing hormones by the hypothalamus and LH secretion by the pituitary gland. A decrease in androgens stimulates the secretion of releasing hormones by the hypothalamus and LH secretion by the pituitary gland.) |
|
Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth? |
androgens – Androgens, such as testosterone, are responsible for both sperm production and the secondary sex characteristics of males. |
|
Which pituitary secretion stimulates sperm production? |
FSH |
|
Which pituitary secretion stimulates the testes to secrete androgens? |
LH |
|
Sperm develop in the _____. |
seminiferous tubules |
|
A fertilized egg usually implants itself and develops in the _____. |
uterus |
|
A rapid increase in the _____ level stimulates ovulation |
luteinizing hormone |
|
After ovulation, high levels of _____ inhibit _____ secretion. |
estrogen and progesterone … FSH and LH |
|
Developing ovarian follicles primarily secrete _____. |
estrogens |
|
If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum. |
human chorionic gonadotropin |
|
If there is no fertilization, degeneration of the corpus luteum results in a drop in _____, which results in the sloughing off of the uterus’s endometrium. |
estrogen and progesterone |
|
Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle. |
14 |
|
What is the usual site of the fertilization of an egg cell? |
oviduct |
|
Some methods of contraception, such as birth control pills and patches, use synthetic hormones to manipulate the ovarian cycle in females. Which statements correctly explain how the hormone-based contraceptives affect the female reproductive cycle? |
– The low dose of estradiol in the combination pill prevents the surge in LH production. – The low doses of progestin and estradiol in the combination pill have a negative feedback effect on the hypothalamus, blocking ovulation. – The progestin in the progestin-only pill causes changes in the endometrium that prevent implantation. |
|
True or false? Humans form gametes by a process called gametogenesis. |
True |
|
What role do germ cells play in gametogenesis? |
B.)They produce cells that divide by mitosis and then undergo meiosis to form gametes. |
|
What products are formed when a diploid cell undergoes meiosis? |
A.)Four haploid cells. |
|
Which of the following statements about oogenesis in humans is true? |
B.)Beginning at puberty, a primary oocyte completes its first meiotic division to form a secondary oocyte and a polar body approximately every month. |
|
Which diploid cells are produced by an embryonic germ cell? A.)Polar body. |
C.) Spermatogonia. |
|
True or false? The production of sperm begins at puberty when spermatogonia undergo meiosis I to form primary spermatocytes, which then undergo meiosis II to form secondary spermatocytes. These secondary spermatocytes go on to form spermatids, which mature into sperm cells. |
False |
|
How does spermatogenesis differ from oogenesis? A.)Production of the cells that will mature into gametes is complete by birth in spermatogenesis. |
D.)Diploid cells give rise to four functional gametes in spermatogenesis. |
|
Suppose you wanted to get started in the animal-breeding business. You could start out with only one of most of the following animals, but you would have to start with at least two _____. A.)sea anemones |
C.)frogs |
|
Which of the following is a form of sexual reproduction? A.)budding |
E.)hermaphroditism |
|
Some salamander and insect populations consist of only genetically identical females. This occurs because _____. A.)males are killed at birth by their mothers |
D.)sperm do not fuse with eggs during reproduction, but the eggs develop into embryos anyway |
|
External fertilization occurs mostly in _____. A.)aquatic animals |
A.)aquatic animals |
|
Vertebrates became truly terrestrial with the development of the amniotic egg. The most primitive vertebrates to possess such eggs are the _____. A.)mammals |
E.)reptiles |
|
Which of the following is not found in or on a healthy human ovary? A.)egg cell |
C.)endometrium |
|
Which of the following correctly traces the path of sperm from their site of production to their exit from a man’s body? A.)seminiferous tubule … epididymis … vas deferens … urethra |
A.)seminiferous tubule … epididymis … vas deferens … urethra |
|
In humans, oogenesis in comparison to spermatogenesis is different in that _____. A.)the sequence from primary oocyte to ovum is interrupted by a relatively long resting period |
E.)All of the above are correct. |
|
A peak in _____ triggers ovulation around the _____ day of the monthly cycle. A.)estrogen … 20th |
E.)LH … 14th |
|
During the first trimester _____. A.)the mother may feel movements, and fetal activity may be visible through the abdominal wall |
E.)the fetus is most vulnerable to exposure to drugs and radiation |
|
During human gestation, rudiments of all organs develop A.)while the embryo is in the oviduct. |
D.)in the first trimester. |
|
Peaks of LH and FSH production occur during A.)the period just before ovulation. |
A.)the period just before ovulation. |
|
Which of the following is a true statement? A.)Estrous cycles are not controlled by hormones. |
B.)The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles. |
|
A fertilized egg usually implants itself and develops in the _____. A.)uterus |
A.)uterus |
|
A rapid increase in the _____ level stimulates ovulation. A.)progesterone |
C.)luteinizing hormone |
|
After ovulation, high levels of _____ inhibit _____ secretion. A.)estrogen and progesterone … FSH and LH |
A.)estrogen and progesterone … FSH and LH |
|
Developing ovarian follicles primarily secrete _____. A.)progesterone |
B.)estrogens |
|
If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum. A.)progesterone |
E.)human chorionic gonadotropin |
|
If there is no fertilization, degeneration of the corpus luteum results in a drop in _____, which results in the sloughing off of the uterus’s endometrium. A.)FSH |
B.)estrogen and progesterone |
|
Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle. A.)1 |
C.)14 |
|
What is the usual site of the fertilization of an egg cell? A.)uterus |
C.)oviduct |
|
Which characteristic of the male reproductive system is not variable among animal species that reproduce sexually? A.)Presence of genitalia. |
A.)Presence of genitalia. |
|
True or false? The basic functions of the human female reproductive system are to produce eggs, develop offspring, and make hormones. |
True |
|
Which function is not performed by the male reproductive system? A.)Production and storage of oogonia.. |
A.)Production and storage of oogonia.. |
|
Which hormone spikes midway through the menstrual cycle and triggers ovulation? A.)Estradiol. |
D.)Luteinizing hormone (LH). |
|
Which male reproductive structures are responsible for the transport and delivery of sperm? A.)Vas deferens, urethra, and penis. |
A.)Vas deferens, urethra, and penis |
|
Where does a human fetus develop? A.)Uterus. |
A.)Uterus. |
|
Which of the following events occurs at the onset of the luteal phase of the menstrual cycle? A.)Release of high levels of FSH. |
C.)Development of the corpus luteum. |
|
Which of the following is not properly paired? A.)testosterone – estradiol |
C.)seminiferous tubule – cervix |
|
Which of the following characterizes parthenogenesis? A.)Specialized groups of cells grow into new individuals. |
B.)An egg develops without being fertilized. |
|
In male mammals, excretory and reproductive systems share A.)the urethra. |
A.)the urethra. |
|
For which of the following is the number the same in spermatogenesis and oogenesis? A.)functional gametes produced by meiosis. |
D.)meiotic divisions required to produce each gamete. |
|
Which of the following statements about human reproduction is false? A.)Spermatogenesis and oogenesis require different temperatures. |
E.)The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules. |
|
Sperm exit a male’s body via the _____. A.)ejaculatory duct |
B.)urethra |
|
The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____. A.)positive … hypothalamus … pituitary gland |
B.)negative … hypothalamus … pituitary gland |
|
Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth? A.)androgens |
A.)androgens |
|
Which pituitary secretion stimulates sperm production? A.)LH |
E.)FSH |
|
Which pituitary secretion stimulates the testes to secrete androgens? A.)LH |
A.)LH |
|
Sperm develop in the _____. A.)prostate gland |
C.)seminiferous tubules |
|
The "reproductive handicap" for sexual reproduction refers to |
have only half the offspring are females |
|
Animals utilizing external fertilization are typically |
aquatic animals |
|
True or false? Humans form gametes by a process called gametogenesis. |
true |
|
What role do germ cells play in gametogenesis? |
they produce cells that divide by mitosis and then undergo meiosis to form gametes |
|
What products are formed when a diploid cell undergoes meiosis? |
four haploid cells |
|
Which of the following statements about oogenesis in humans is true? |
beginning at puberty, a primary oocyte completes its first meiotic division to form a secondary oocyte and a polar body approximately every month |
|
Which diploid cells are produced by an embryonic germ cell? |
spermatognoia |
|
How does spermatogenesis differ from oogenesis? |
diploid cells give rise to four functional gametes in spermatogenesis |
|
The path of sperm from their site of production to their exit from a man’s body |
seminiferous tubule>>epididymis>>vas defernes>>urethra |
|
A fertilized egg usually implants itself and develops in the |
uterus |
|
A rapid increase in the____level stimulates ovulation |
luteinizing hormone |
|
After ovulation, high levels of____inhibit____secretion |
estrogen and progesterone….FSH and LH |
|
Developing ovarian follicles primarily secrete |
estrogens |
|
If there is fertilization, secretion of____by the early embryo maintains the corpus luteum |
human chorionic gonadotropin |
|
If there is no fertilization, degeneration of the corpus luteum results in a drop in____, which results in the sloughing off of the uterus’s endometrium |
estrogen and progesterone |
|
Ovulation usually occurs on or about day___of a 28 day ovarian cycle |
14 |
|
What is the usual site of the fertilization of an egg cell? |
oviduct |
|
Sperm become capable of moment while in the____ |
epididymis |
|
Sperm exit a male’s body via the___ |
urethra |
|
The secretion of androgens is regulated by a____feedback mechanism involving the___and_____ |
negative…hypothalamus…pituitary gland |
|
Which hormone is directly responsible for triggering the development of the secondary sex characteristic of males, such as beard growth? |
androgens |
|
Which pituitary secretion stimulates sperm production? |
FSH |
|
Which pituitary secretion stimulates the testes to secrete androgens? |
LH |
|
Sperm develop in the____ |
seminiferous tubules |
|
Androgens |
deepening of voice, development of facial hair, increased aggressiveness, increased muscle mass, testosterone |
|
Estrogens and progesterone |
increased water retention, breast development, fat deposition in hips, changes in calcium metabolism, estradiol |
|
Hypothalamus secretes GnRH |
stimulates the pituitary to secrete LH and FSH; which stimulates follicle growth and secretion of estradiol; which at high levels causes the pituitary to increase production of LH and FSH; follicle maturation and ovulation; corpus luteum secretes estradiol and progesterone; causes the pituitary to inhibit production of LH and FSH; corpus luteum disintegrates causes a decline in estradiol and progesterone; ending inhabitation of the hypothalamus and pituarity and allowing secretion of LH and FSH |
|
Hormone-based contraceptives affect the female reproductive cycle? |
the progestin in the progestin-only pill causes changes in the endometrium that prevent implantation; the low doses of progestin and estradiol in the combination pill have a negative feedback effect of the hypothalamus, blocking ovulation; the low dose of estradiol in the combination pill prevents the surge in LH production |
|
The anatomical location for the typical union of a sperm and an egg (conception) is the____ |
oviducts |
|
A surge in what hormone immediately precedes ovulation? |
LH and FSH |
|
Elevated levels of what hormone most likely stimulate the LH/FSH surge just before ovulation? |
estradiol |
|
Most animals exhibit reproductive cycles related to |
changing seasons |
|
Reproductive cycles are controlled |
by hormones and environmental cues |
|
Hermaphroditism |
each individual has male and female reproductive systems; two hermaphrodites can mate, and some hermaphrodites can self-fertilize |
|
The mechanisms of fertilization |
the union of egg and sperm, play an important part in sexual reproduction |
|
In external fertilization |
eggs shed by the female are fertilized by sperm in the external environment |
|
In internal fertilization |
sperm are deposited in or near the female reproductive tract, and fertilization occurs within the tract |
|
All fertilization requires |
environmental cues, pheromones, courtship behavior |
|
Some animals have eggs with |
calcium-and protein-containing shells |
|
Some other animals retain the embryo |
which develops inside the female |
|
In many animals, parental |
care helps ensure survival of offspring |
|
To reproduce sexually |
animals must produce gametes |
|
In most species individuals have |
gonads, organs that produce gametes (some simple systems do not have gonads, but gametes form from undifferentiated tissue) |
|
Monogamy is |
relatively rare among animals |
|
An advantage of internal fertilization over external fertilization is that |
internal fertilization prevents the drying out of gametes in a dry environment |
|
The mammary glands are not |
part of the reproductive system but are important to mammalian reproduction |
|
Within the glands |
small sacs of epithelial tissue secrete milk |
|
Gametogenesis |
the production of gametes |
|
Sperm are small and motile |
and must pass from male to female |
|
Eggs are |
larger and carry out their function within the female |
|
Spermatogenesis differs from oogenesis in three ways |
all four products of meiosis develop into sperm while only one of the four becomes an egg; spermatogenesis occurs throughout adolescence and adulthood; sperm produced continuously without the prolonged interruptions in oogenesis |
|
Human reproduction is |
coordinated by hormones |
|
Gonadotropoin-releasing hormone (GnRH) is secreted by the |
hypothalamus and directs the release of FSH and LH from the anterior pituitary |
|
FSH and LH regulate processes in the gonads |
and the production of sex hormones (estrogens and androgens have multiple effects, including the promotion of specific behaviors) |
|
Hormones closely link the two cycles of female reproduction |
changes in the uterus define the menstrual cycle (also called the uterine cycle) and changes in the ovaries define the ovarian cycle |
|
The sequential release of GnRH then |
FSH and LH stimulates the follicle growth |
|
Follicle growth and an increase in the hormone |
estradiol characterize the follicular pause of the ovarian cycle |
|
The follicular phase ends at ovulation |
and the secondary oocyte is released |
|
Following ovulation, the follicular tissue left behind |
transforms into the corpus luteum; this is the luteal phase |
|
The corpus luteum disintegrates |
and ovarian steroid hormones decrease |
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Hormones coordinate the uterine cycle with the ovarian cycle |
thickening of the endometrium during the proliferative phase coordinates with the follicular phase; secretion of nutrients during the secretory phase coordinates with the luteal phase; shedding of the endometrium during the menstrual flow phase coordinates with the growth of new ovarian follicles |
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After about 500 cycles, human females undergo |
menopause, the cessation of ovulation and menstruation |
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Menopause is |
very unusual among animals; menopause might have evolved to allow a mother to provide better care for her children and grandchildren |
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Menstrual cycles are characteristic only of |
humans and other primates; the endometrium is shed from the uterus in a bleeding called menstruation; sexual receptivity is not limited for a time frame |
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Estrous cycles are |
characteristic of most mammals |
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In the estrous cycles |
the endometrium is reabsorbed by the uterus; sexual receptivity is limited to a "heat" period; the length and frequency of estrus cycles vary from species to species |
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FSH promotes the activity of |
Sertoli cells, which nourish developing sperm |
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LH regualtes leydig cells |
which secrete testosterone and other androgens, which in turn promote spermatogenesis |
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The first trimester is the main period of |
organogenesis, development of the body organs |
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All the major structures are present by |
8 weeks and the embryo is called a fetus |
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Changes occur in the mother |
mucus plug to protect against infection; growth of placenta and uterus; cessation of ovulation and the menstrual cycle; breast enlargement; nausea is also very common |
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Splitting of the embryo during the first month of development results in |
genetically identical twins |
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Release and fertilization of two eggs result in |
fraternal and genetically distinct twins |
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During the second trimester |
the fetus grows and is very active; the mother may feel fetal movements; the uterus grows enough for the pregnancy to become obvious |
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Third trimester |
GROWTH; local regulators and hormones induce and regulate labor |
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Contraception |
the deliberate prevention of pregnancy, can be achieved in a number of ways |
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Contraceptive methods fall into three categories |
preventing release of eggs and sperm; keeping sperm and egg apart; preventing implantation of an embryo |
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Female birth control pills are |
hormonal contraceptives with pregnancy rate of less than 1% |
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Sterilization is |
permanent and prevents the release of gametes |
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Tubal ligation |
ties off the oviducts |
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Bipolar coagulation |
the most popular method of laparoscopic female sterilization, this method uses electrical current to cauterize sections of the fallopian tube |
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Vasectomy |
ties off the vas deferens |
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The rhythm method |
or natural family planning, is to refrain from intercourse when conception is most likely; it has a pregnancy rate of 10-20% |
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Coitus interruptus |
the withdrawal of the penis before ejaculation, is unreliable |
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Barrier methods |
block fertilization with a pregnancy rate of less than 10% |
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Condom |
fits over the penis |
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A diaphragm |
is inserted into the vagina before intercourse |
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IUDS ae |
inserted into the uterus and interfere with fertilization and implantation; the pregnancy rate is less than 1% |
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Plan B One-step |
it may prevent or delay ovulation; it may interfere with fertilization of an egg; it is also possible that this type of emergency birth control prevents implantation of a fertilized egg in the uterus by altering its liing |
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Plan B One-step i snot the same as RU-486 |
which is an abortion pill. it does not cause a miscarriage or abortion, it does not stop development of a fetus once the fertilized egg implants in the uterus |
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Abortion is the |
termination of a pregnancy; the drug RU 486 results in an abortion within the first 7 weeks of an pregnancy |
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Spontaneous abortion |
or miscarriage, occurs in up to one-third of all pregnancies |
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The combination of estrogen and progesterone in most oral contraceptive for women |
inhibits secretion LH and FSH by the anterior pituitary, thus inhibiting follicle development |
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Two contraceptive methods that are similar in function |
tubal ligation and vasectomy |
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Amniocentesis and chorionic villus sampling are |
invase techniques in which amniotic fluid or fetal cells are obtained for genetic analysis |
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Noninvasive procedure usually |
use ultrasound imaging to detect fetal condition |
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Genetic testing of the fetus |
poses ethical questions and can present parents with difficult decision |
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Modern technology can provide infertile couples with |
assisted reproductive technologies |
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In vitro fertilization (IVF) |
mixes eggs with sperm in culture dishes and returns the embryo to the uterus at the 8-cell stage |
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Sperm are injected directly into an egg in a type of IVF called |
intracytoplasmic sperm injection (ICSI) |
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Gonorrhea |
bacteria; scar tissue, blindness in infants, antibiotic resistant |
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Syphilis |
bacteria; multiple system damage and fatal; 4 out of 1000 infants infected |
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Chlamydia |
bacteria; very common and often undetected; may cause sterility |
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Genital herpes |
virus; in newborns can result in death |
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Genital warts |
virus; may be implicated in cervical cancer |
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Trichomoniasis |
protozoan; parasite inhabits uro-genital tract and spreads through intercourse or toilet facilities; can result in sterility |
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A blood sample taken from a woman in her 40s showing high levels of estrogen, progesterone, hCG, and prolactin suggests that |
she is pregnant |
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An infant suckling on the breast of a woman who has recently given birth sends a nerve impulses to the pituitary gland. THe pituitary gland then secretes oxytocin, which stimulates the mammary glands in the breasts to release milk. What type of hormonal feedback is this? |
positive feedback |
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