Deck 6: Sexual Development

Question 1

Sperm capacitation

A) stimulates the sperm to complete meiosis.
B) neutralizes the pH of the vagina.
C) triggers the release of calcium ions, which protect the sperm from enzymes in the female reproductive tract.
D) removes masking proteins from the sperm, allowing them to swim more forcefully and to interact with the oocytes.
E) stimulates binding to the polar body on the oocyte.

Answer 1

D

Question 2

The process of _______ removes proteins on the outer surface of the sperm, making them swim more forcefully.

A) fertilization
B) conception
C) the acrosome reaction
D) capacitation
E) ovulation

Answer 2

D

Question 3

If capacitated sperm are placed in a glass dish containing a mixture of unfertilized oocytes and conceptuses, the sperm will be able to bind to

A) neither the oocytes nor the conceptuses.
B) both the oocytes and the conceptuses.
C) only the unfertilized oocytes.
D) only the conceptuses.
E) only the conceptuses that have pronuclei.

Answer 3

C

Question 4

The acrosome reaction occurs when sperm reach the _______ that surround(s) the ovum.

A) morula
B) blastocyst
C) oviducts
D) cytoplasm
E) zona pellucida

Question 5

The moment a sperm fuses with the plasma membrane of an ovum, the concentration of _______ within the ovum is increased briefly.

A) free calcium ions
B) X chromosomes
C) free chloride ions
D) free potassium ions
E) free magnesium ions

Question 6

The conceptus remains in the oviduct for about _______ day(s) after ovulation

A) 1
B) 3
C) 7
D) 14
E) 21

Question 7

The implantation process requires the presence of both progesterone and estrogens, which are secreted by the _______ in the mother's ovary.

A) placenta
B) Leydig cells
C) amnion
D) chromosomes
E) corpus luteum

Question 8

The presence of _______ in the mother's blood or urine is a sign that pregnancy has occurred.

A) DNA
B) DAX-1
C) SRY
D) hCG
E) AMH

Question 9

Human chorionic gonadotropin (hCG), a hormone released by a conceptus and the placenta, is chemically and functionally similar to luteinizing hormone (LH). As such, hCG supports early pregnancy by

A) stimulating the corpus luteum to maintain its secretion of estrogen and progesterone.
B) stimulating the hypothalamus to secrete GnRH.
C) inhibiting the secretion of androgens.
D) causing the corpus luteum to regress, thus preventing subsequent ovulation.
E) acting upon LH receptors in the endometrium to prevent it from being shed during menstruation.

Question 10

The _______ is the organ by which the fetus and its mother exchange nutrients and hormones.

A) mesoderm
B) placenta
C) corpus luteum
D) amnion
E) umbilical cord

Question 11

_______ cells have the potential to divide and develop into any specialized cell type.

A) Leydig
B) Sertoli
C) Embryonic stem
D) Adult stem
E) Granulosa

Question 12

The embryonic phase of development is completed by about _______ weeks after conception.

A) 2
B) 4
C) 6
D) 8
E) 10

Question 13

Alfred Jost did an experiment in which he removed the gonads from male and female rabbit fetuses and then observed their subsequent sexual development. All of the gonadectomized animals developed a female phenotype. This experiment demonstrated

A) the importance of the X chromosome in female development.
B) the importance of the Y chromosome in male development.
C) the importance of the ovaries in female development.
D) the importance of the testes in male development.
E) that rabbits are not good research models.

Question 14

Which of the following represents the correct order of sexual development?

A) Determination of chromosomal sex, secretion of hormones, development of gonads, development of reproductive tracts
B) Secretion of hormones, development of gonads, determination of chromosomal sex, development of reproductive tracts
C) Secretion of hormones, determination of chromosomal sex, development of gonads, development of reproductive tracts
D) Determination of chromosomal sex, development of gonads, secretion of hormones, development of reproductive tracts
E) Determination of chromosomal sex, development of reproductive tracts, secretion of hormones

Question 15

All individuals possess which of the following sex chromosome(s)?

A) X
B) Y
C) X and Y
D) SRY
E) DAX-1

Question 16

Which of the following sex chromosomes is carried by a sperm?

A) X
B) Y
C) X or Y
D) X and Y
E) SRY

Question 17

Which of the following sex chromosomes is carried by an ovum?

A) X
B) Y
C) X or Y
D) X and Y
E) SRY

Question 18

The testes and ovaries become differentiated from precursor structures known as

A) genital tubercles.
B) genital ridges.
C) transcription factors.
D) Wolffian ducts.
E) Müllerian ducts.

Question 19

If an XY individual is missing the SRY gene on the Y chromosome, that individual will develop

A) an ovotestis and ambiguous genitalia.
B) testes and female reproductive structures.
C) ovaries and male reproductive structures.
D) testes and male reproductive structures.
E) ovaries and female reproductive structures.

Question 20

Girls with Turner syndrome lack normal ovaries; instead of oocytes, their ovaries primarily contain connective tissue. This observation suggests that

A) estrogen is essential for normal ovary development.
B) two X chromosomes are essential for normal ovary development.
C) even with two X chromosomes, the presence of a Y chromosome inhibits normal ovary development.
D) the presence of anti-Müllerian hormone inhibits normal ovary development.
E) high levels of androgens inhibit normal ovary development.

Question 21

Girls with _______ syndrome usually lack normal ovaries, do not enter puberty, and are infertile.

A) XYY
B) Klinefelter
C) triple X
D) androgen insensitivity
E) Turner

Question 22

_______ men are physically healthy but often exhibit disability in their language skills.

A) XY
B) XYY
C) XO/XY
D) XXY
E) XY/XO

Question 23

A gene called _______, located on the X chromosome, is important for development of the ovaries.

A) SRY
B) DAX-1
C) androgen receptor
D) AMH
E) FSH

Question 24

Inhibiting the expression of the FOXL9 gene in an adult female mouse causes her ovaries to transform into testes. This experimental result supports which of the following statements?

A) The Y chromosome is necessary for testicular development.
B) Gonadal differentiation can occur only during a critical period in fetal life.
C) The FOXL9 gene is essential for the expression of female sexual behavior.
D) FOXL9 regulates the sexual differentiation of the external genitalia.
E) FOXL9 is important in inhibiting testicular development.

Question 25

A person with gonadal intersexuality

A) possesses both ovarian and testicular tissue.
B) possesses the gonads of one sex and the external genitalia of the other sex.
C) has a gender identity that is at odds with his or her biological anatomy.
D) is able to self-fertilize.
E) has genital ridges that failed to develop during fetal life.

Question 26

The _______ ducts are precursors to the male reproductive tracts.

A) primordial germ cell
B) yolk sac
C) Müllerian
D) DHT
E) Wolffian

Question 27

Individuals with an XY genotype but nonfunctional androgen receptors will have

A) male reproductive structures, but their genitals will be very small due to the inability of testosterone to stimulate their growth.
B) female reproductive structures due to the inability of testosterone to stimulate development of the Wolffian ducts.
C) neither male nor female internal reproductive structures due to a lack of testosterone and anti-Müllerian inhibiting hormone.
D) neither male nor female internal reproductive structures due to the inability of testosterone to stimulate development of the Wolffian ducts, while the presence of anti-Müllerian hormone causes the Müllerian ducts to regress.
E) female reproductive structures because their genital ridges convert from testes to ovaries.

Question 28

A genetic male mouse given an antagonist to AMH during fetal life will most likely possess _______ internal reproductive structures and _______ external genitalia.

A) male; female
B) female; female
C) both male and female; female
D) both male and female; male
E) neither male nor female; male

Question 29

The peptide hormone _______, secreted by the Sertoli cells of the testes, prevents development of the female reproductive tract.

A) AMH
B) inhibin
C) DHT
D) prolactin
E) vasopressin

Question 30

Individuals with androgen insensitivity syndrome have

A) XY chromosomes and normal testes, male internal reproductive structures, and a male external phenotype.
B) XY chromosomes and normal testes, female internal reproductive structures, and a female external phenotype.
C) XY chromosomes and normal testes, both male and female internal reproductive structures, and a male external phenotype.
D) XY chromosomes and normal testes, both male and female internal reproductive structures, and a female external phenotype.
E) XY chromosomes and normal testes, neither male nor female internal reproductive structures, and a female external phenotype.

Question 31

Androgen insensitivity syndrome can be mimicked in genetic males who lack

A) 5 $\alpha$ -reductase.
B) aromatase.
C) functional FSH receptors on their Sertoli cells.
D) functional LH receptors on their Leydig cells.
E) dihydrotestosterone.

Question 32

The common exit of the gastrointestinal and urogenital systems present during fetal development is the

A) urethral fold.
B) cloaca.
C) genital swelling.
D) genital tubercle.
E) urethral swelling.

Question 33

The clitoris develops from the

A) urethral folds.
B) genital swellings.
C) genital tubercle.
D) labial folds.
E) labio-scrotal folds.

Question 34

The glans penis develops from the

A) urethral folds.
B) genital swellings.
C) genital tubercle.
D) labial folds.
E) labio-scrotal folds.

Question 35

The labia majora develop from the _______, and the labia minora develop from the _______.

A) anal folds; raphe
B) urethral folds; genital tubercle
C) genital tubercle; genital swellings
D) genital swellings; urethral folds
E) urogenital sinus; raphe

Question 36

Congenital adrenal hyperplasia is associated with a defect in steroid synthesis by the adrenal gland, leading to reduced production of corticosteroids and increased production of androgens. A consequence of this condition is the _______ in _______.

A) masculinization of the external genitalia; girls.
B) feminization of the external genitalia; boys
C) development of testes; girls
D) regression of Müllerian ducts; girls
E) regression of the Wolffian ducts; boys

Question 37

Although much of what we know about sexual development comes from manipulating hormones in animal models, studies of girls and women affected by CAH can provide insight into the

A) effects of high levels of estrogens on the developing brain.
B) role of the X chromosome on sexual differentiation.
C) effects of androgens on the developing brain.
D) effects of estrogen receptor insensitivity on genital development.
E) effects of corticosteroids on human sexuality.

Question 38

Dihydrotestosterone has been shown to play an important role in the development of the male external genitalia. Low levels of DHT have been associated with failure of the

A) genital swelling to form the glans of the penis.
B) urethral folds to fuse on the underside of the penis.
C) gonads to develop into testes.
D) Müllerian ducts to regress.
E) SDN-POA in the hypothalamus to become masculinized.

Question 39

In male fetuses, the conversion of testosterone to _______ is required for the normal development of the external genitalia.

A) aromatase
B) DHT
C) estrogen
D) progesterone
E) AMH

Question 40

At 6 to 7 months following conception, the testes descend into the _______; shortly before birth they enter the _______.

A) cervical tissue; pelvis
B) pelvis; scrotum
C) cervical tissue; scrotum
D) scrotum; pelvis
E) pelvis; labia

Question 41

Genetic males with 5 $\alpha$ -reductase deficiency may be born with ambiguous or female-like genitalia because

A) their bodies cannot convert testosterone to estrogen.
B) their bodies cannot convert testosterone to dihydrotestosterone (DHT).
C) they lack functional androgen receptors.
D) they lack functional testes.
E) their bodies do not make anti-Müllerian hormone.

Question 42

_______ is a condition in males in which the urethral folds fail to fully enclose the urethra.

A) Cryptorchidism
B) Hypospadias
C) AMH deficiency
D) SRY deficiency
E) DAX-1 deficiency

Question 43

Three months after birth, the condition of undescended testicles is called

A) paraphimosis.
B) hypospadias.
C) AMH deficiency.
D) phimosis.
E) cryptorchidism.

Question 44

Approximately _______% of boys are affected by cryptorchidism.

A) 1
B) 5
C) 10
D) 15
E) 20

Question 45

A sexually dimorphic cell group in the medical preoptic area of the human hypothalamus is the

A) INAH1.
B) INAH2.
C) INAH3.
D) INAH4.
E) INAH5.

Question 46

The SDN-POA is larger in _______ than in _______.

A) male rodents; female rodents
B) men; women
C) female rodents; male rodents
D) women; men
E) boys; girls

Question 47

Administering testosterone to female rats during a period immediately before and after birth leads to male-typical development of the SDN-POA. Administration of testosterone to an adult female has no effect on the SDN-POA. Which of the following is the best interpretation of these results?

A) Testosterone is not involved in the development of the SDN-POA.
B) Testosterone in adulthood inhibits the development of the SDN-POA.
C) Female and male brains are different.
D) The testosterone-treated female rats will behave like males.
E) Testosterone must be present during a restricted sensitive period of development in order to lead to a male-like SDN-POA.

Question 48

When Alfred Jost removed the ovaries from female rat fetuses, the animals developed as females. However, these females were unlikely to exhibit female sexual behavior as adults because

A) typical female sexual behavior requires organizational effects of estrogens during early development.
B) typical female sexual behavior requires activational effects of estrogens during early adulthood.
C) typical female sexual behavior requires both organizational and activational effects of estrogens both during early development and in adulthood.
D) in the absence of ovaries, the brain becomes masculinized, so these animals would be expected to show male-typical sexual behavior.
E) they lacked a vagina.

Question 49

If the SRY gene "jumps" onto an X chromosomes during meiosis, the resulting XX offspring will develop as a male. The observation that these individuals have defective spermatogenesis suggests that

A) other genes on the Y chromosome are important for male fertility.
B) other genes on the X chromosome are necessary for male fertility.
C) other genes on the Y chromosome are necessary for Wolffian duct development.
D) other genes on the Y chromosome are necessary for Müllerian duct development.
E) testosterone levels are very low in these individuals.

Question 50

The relative contributions of biological and environmental factors on sexual development have been explored in various ways, including studies of the offspring of pregnant mothers exposed to stress or hormone-related drugs, and studies of the effects of same-sex or mixed-sex housing on the development of sexual behavior in non-human primates. Which of the following statements best reflects the conclusions derived from these studies?

A) Genes are responsible for guiding development before birth, but environmental and social factors take over after birth.
B) Environmental and social factors are important in shaping sexual development and biological factors are largely irrelevant.
C) Biological factors are important in shaping sexual development and environmental factors are largely irrelevant.
D) Environmental and biological factors interact during and after fetal life to affect sexual development and behavior.
E) Taking prescriptions drugs during pregnancy always has adverse effects on fetal development.

Question 51

Although sex hormone levels are very low in both boys and girls from around 6 to 9 months of age until puberty, there are sex differences in personality and behavior in young children. These differences are believed to be largely due to

A) effects of socialization on the development of gender-stereotyped behaviors.
B) sex differences in LH and FSH in early childhood.
C) the fact that puberty has been occurring at younger ages in Western cultures.
D) activational effects of hormones in early childhood.
E) organizational effects of prenatal hormones.

Question 52

Boys are generally taller than girls after puberty because the pubertal growth spurt

A) starts earlier and lasts longer in boys.
B) starts earlier and is much shorter in girls.
C) starts earlier in girls and lasts about the same amount of time in boys and girls.
D) starts around the same time in boys and girls and lasts longer in boys.
E) starts around the same time and lasts about the same amount of time in both boys and girls.

Question 53

_______ is the transition to sexual maturity.

A) Puberty
B) Differentiation
C) Development
D) Gubernacula
E) Morula

Question 54

The pubertal growth spurt in the contemporary U.S. population starts at an average age of _______ for girls and _______ for boys.

A) 8; 10
B) 9; 11
C) 11; 13
D) 13; 15
E) 15; 17

Question 55

_______ are examples of secondary sex characteristics that develop during puberty.

A) Ovarian and testicular development
B) Growth of body hair, changes in fat and muscle distribution, and the development of breasts in females
C) Maturation of the Wolffian ducts and regression of the Müllerian ducts in males
D) Activation of the Y chromosome in males and the X chromosome in females
E) Development of gender identity and sexual orientation

Question 56

Menstruation is often _______ for the first year or two after menarche, and during this period menstrual cycles tend to be _______.

A) regular; ovulatory
B) irregular; anovulatory
C) regular; anovulatory
D) spasmodic; fertile
E) spasmodic; infertile

Question 57

Which of the following is not an early sign of puberty for boys?

A) Enlargement of the testes
B) Enlargement of the penis
C) Change in voice
D) Gynecomastia
E) A drop in testosterone levels

Question 58

Among females in the U.S. population, which group is the earliest to show visible signs of puberty?

A) Caucasians
B) Native Americans
C) Hispanics
D) Chinese Americans
E) African-Americans

Question 59

Estrogens play many important roles during puberty. Which of the following characteristics would not be expected in a girl who could not produce estrogen or lacked estrogen receptors?

A) Poor breast development
B) Tall stature for her age
C) Short stature for her age
D) Primary amenorrhea
E) Growth of pubic hair

Question 60

Which of the following is not thought to contribute to the timing of the onset of puberty?

A) Ethnicity
B) Body weight
C) Hormone-like environmental pollutants
D) Chronological age
E) Societal pressure

Question 61

Androgens can contribute to the development of acne by increasing secretion of sebaceous glands during puberty. However, androgen receptor blockers would not be a good acne treatment because they could interfere with

A) pubertal development in males only.
B) pubertal development in females only.
C) pubertal development in both females and males.
D) the development of the Wolffian ducts.
E) the sexual differentiation of the SDN-POA.

Question 62

Androgen levels rise steadily in both sexes during puberty, but they reach much higher levels in _______ than in _______.

A) males; females
B) females; males
C) Asian Americans; African-Americans
D) XXY males; XY males
E) animals; humans

Question 63

The initial pubertal rise in androgens in both sexes is due to activity of the

A) testes.
B) ovaries.
C) pancreas.
D) adrenal glands.
E) thyroid gland.

Question 64

Gonadotropin secretion is triggered by an increase in secretion of _______ by the _______.

A) GnRH.; hypothalamus
B) GnRH; pituitary
C) LH; hypothalamus
D) LH; pituitary
E) FSH; hypothalamus

Question 65

The timing of puberty correlates better with _______ than with _______.

A) chronological age; body weight
B) body weight; chronological age
C) waist-to-hip ratio; chronological age
D) chronological age; waist-to-hip ratio
E) waist-to-hip ratio; body weight

Question 66

Women who have never had a menstrual period have

A) secondary amenorrhea.
B) leptin excess.
C) endocrine disruption.
D) primary amenorrhea.
E) leptin deficiency.

Question 67

Females who engage in activities like gymnastics, ballet, and long-distance running often suffer from either primary or secondary amenorrhea. This is most likely due to

A) extremely low levels of body fat.
B) anabolic steroid abuse.
C) performance anxiety.
D) high levels of leptin.
E) low self-esteem.

Question 68

A key event that triggers puberty is an increase in GnRH secretion by the hypothalamus, which subsequently activates gonadotropin secretion. Precocious (early-onset) puberty is often treated by manipulating this hormonal system with

A) pulsatile administration of LH and FSH analogs.
B) pulsatile administration of GnRH analogs.
C) administration of LH and FSH analogs at constant high levels.
D) administration of GnRH analogs at constant high levels.
E) administration of high doses of estrogen to reduce GnRH levels through feedback inhibition.

Question 69

Puberty is considered _______ if pubic hair, and/or breast or testes enlargement begins as early as 5-6 years of age.

A) precious
B) progressive
C) precocious
D) predominant
E) morula

Question 70

Puberty is considered _______ if signs of maturation are not evident by 13 (girls) or 14 (boys) years of age.

A) precocious
B) predominant
C) delayed
D) extreme
E) progressive

Question 71

Intersexuality raises complex social and ethical issues primarily because affected individuals

A) are infertile.
B) are homosexual.
C) do not always fit the societal and medical definitions of "normal."
D) are integrated well into society.
E) often have criminal tendencies.

Question 72

The removal of masking proteins from the outer surface of a sperm is called

A) the acrosome reaction.
B) exposita pellucida.
C) capacitation.
D) amplification.
E) fertilization.

Question 73

What is the relationship between bourgeonal and the human ovum?

A) They both interact with steroid hormones.
B) They both have a short life of about 24 hours.
C) They are both products of the ovary.
D) They are both aromatic.
E) They are both attractants.

Question 74

Immediately after fertilization, the ovum undergoes

A) a mitotic division.
B) implantation.
C) capacitation.
D) a meiotic division.
E) zona pellucida.

Question 75

The placenta originates from the _______ of the embryo.

A) endoderm and ectoderm
B) ectoderm and mesoderm
C) neural tube
D) mesoderm and endoderm
E) None of the above

Question 76

Fetal hormones

A) prepare the breasts for milk production.
B) inhibit breast development.
C) maintain the pregnant uterus.
D) Both a and c
E) None of the above

Question 77

Fetal hemoglobin is _______ than adult hemoglobin.

A) less mature
B) designed to operate at lower oxygen levels
C) more abundant
D) All of the above
E) None of the above

Question 78

Which of the following is in the correct sequence?

A) SRY gene, testes, male development
B) Testes, SRY gene, male development
C) Male development, SRY gene, testes
D) SRY gene, male development, testes
E) Male development, testes, SRY gene

Question 79

The minimal genetic requirement to ensure male rather than female development is

A) XY chromosomes.
B) an X chromosome.
C) the SRY gene.
D) a Y chromosome.
E) the FOXL2 gene.

Question 80

Which of the following about individuals with Turner syndrome is false?

A) They have a single X chromosome or a single X and a truncated X chromosome.
B) They may have deficient visuospatial skills.
C) They lack functional ovaries.
D) Without treatment, they fail to undergo puberty.
E) They may have deficient language skills.