Biol 12
Reproductive System Review Answers
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Chapter Review
In males, spermatogenesis occurring in seminiferous tubules of the testes produces sperm
that mature in the epididymides and may be stored in the vasa deferentia before entering
the vasa deferentia, along with the secretions produced by seminal vesicles, the prostate
gland, and Cowper’s(bulbourethral) glands. Semen is ejaculated during male orgasm,
when the penis is erect.
Hormonal regulation, involving secretions from the hypothalamus, the anterior
pituitary, and the testes, maintains testosterone produced by the interstitial cells of the
testes at a fairly constant level.
In females, an egg produced by an ovary enters an oviduct, which leads to the
uterus. The uterus opens into the vagina. The external genital area includes the vaginal
opening, the clitoris the labia minora, and the labia majora.
In the non-pregnant female, the ovarian and uterine cycles, are under hormonal
control of the hypothalamus, anterior pituitary, and the female sex hormones estrogen
and progesterone.
If fertilization occurs, the corpus luteum is maintained because of progesterone
production. Progesterone production does not cease, and the embryo implants itself in the
thick endometrial lining.
Estrogen and progesterone maintain the secondary sex characteristics of females,
including less body hair than males, a wider pelvic girdle, a more rounded appearance,
and development of breasts.
Infertile couples are increasingly resorting to alternative methods of reproduction.
Numerous birth-control methods and devices are available for those who wish to prevent
pregnancy.
Sexually transmitted diseases include genital; herpes, which repeatedly flares up;
genital warts, which lead to cancer of the cervix; gonorrhea and chlamydia, which cause
pelvic inflammatory disease (PID); and syphilis, which has cardiovascular and
neurological complications if untreated.
Study Questions
21.1 Male Reproductive System (pages 392-395)
Concept: The male reproductive system is designed for the continuous production of a
large number of sperm within a fluid medium.
1. The male gonads are paired testes found in the scrotum. If the testes do not
descend during development, sterility (inability to produce offspring) results due
to the higher body temperature. Sperm produced by the testes mature within the
epididymides (sing., epididymis) and are propelled into the vasa deferentia (sing.,
vas deferens) by muscular contractions.
2. The penis contains a spongy, erectile tissue that can fill with blood during sexual
arousal. The condition in which the penis fails to become erect is called
impotency. Semen is a thick, whitish fluid that contains sperm and fluids. Each
seminal vesicle joins a vas deferens to form an ejaculatory duct that enters the
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Reproductive System Review Answers
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urethra. The seminal vesicles produce nutrients (fructose) that nourish the sperm.
The prostate gland increases the motility of the sperm. The Cowper’s
(bulbourethral) glands produce a fluid with a lubricating effect. Following
ejaculation, a male may experience a period of time, called the refractory period,
in which stimulation does not bring about an erection. The contractions that expel
semen from the penis are part of a male orgasm.
3. Each lobule in the testes contains one to three coiled seminiferous tubules that
undergo spermatogenesis (meiosis) to form sperm. Sertoli cells support, nourish,
and regulate spermatogenic cells. The middle piece of the sperm contains
microtubules and mitochondria (for energy). The tail, used for motility, has a 9 +
2 microtubule arrangement, as in the middle piece. The head of the sperm
contains a nucleus covered by the acrosome, which stores enzymes needed to
penetrate the layers surrounding the egg.
4. The hypothalamus secretes gonadotropic-releasing hormone (GnRH), which
stimulates the anterior pituitary to secrete follicle stimulating hormone (promotes
spermatogenesis in the seminiferous tubules) and luteinizing hormone (also called
ICSH, it stimulates interstitial cells to produce testosterone). Testosterone and
inhibin exert negative feedback control over the hypothalamus and the anterior
pituitary. Testosterone is necessary for maturation of sperm and secondary sexual
characteristics, such as a beard, voice changes, and bone growth.
The female reproductive system is designed for the monthly production of an egg and
preparation of the uterus to house the developing fetus.
5. List the functions of the following organs of the female reproductive system.
a. ovaries: produce eggs and sex hormones
b. oviducts: conduct eggs and site of fertilization
c. uterus: houses developing fetus
d. cervix: contains opening to uterus
e. vagina: receives penis during intercourse and birth canal
6. The female gonads are called ovaries , and each month one of the ovaries
produces an egg, which bursts from the ovary during ovulation. The oviducts,
which extend from the uterus to the ovaries, sweep up the ovulated egg due to the
finger-like projections called fimbriae and the beating of cilia that line the
oviducts. Fertilization normally occurs in an oviduct. An ectopic pregnancy is one
that begins anywhere outside the uterus.
7. The uterus is a thick-walled, muscular organ with oviducts joining anteriorly and
the cervix posteriorly. The lining of the uterus, called the endometrium ,
participates in the formation of the placenta, which supplies nutrients for the fetus.
Cancer of the cervix may be detected by a PAP smear. The removal of the uterus
is called a hysterectomy . The lining of the vagina has folds that extend during
childbirth and sexual intercourse.
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Reproductive System Review Answers
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8. Collectively, the external genitals of the female are known as the vulva. They
include the labia majora , which extends from the mons pubis, and the labia
minora , which lie inside the labia majora and form the foreskin for the clitoris, an
organ homologous to the penis.
Female Hormone Levels
Concept: Hormones control the monthly reproductive cycle in females and play a
significant role in maintaining pregnancy, should it occur.
9. Each follicle in the ovary contains an oocyte. During oogenesis, a primary follicle
forms a secondary follicle (chromosome number reduced) with the secondary
oocyte pushed to one side of a fluid-filled cavity. The secondary follicle forms a
Graafian follicle in which eventually the follicle wall balloons out on the ovary
surface and bursts (ovulation). The follicle after ovulation develops into the
corpus luteum, which degenerates if there is no pregnancy.
10. In the ovarian cycle, the first half, called the follicular phase, is influenced by the
hormone follicle stimulating hormone from the anterior pituitary. This hormone
causes the follicles to develop, which now secrete estrogen into the blood. As
estrogen levels rise, a feedback mechanism decreases the anterior pituitary
secretion of FSH but causes increased amounts of GnRH from the hypothalamus.
Increased GnRH leads to a surge of luteinizing hormone by the anterior pituitary
and ovulation.
11. During the second half, or secretory phase, of the ovarian cycle, LH promotes the
development of the corpus luteum, which secretes progesterone. As progesterone
blood levels rise, the uterine lining builds up while exerting feedback control over
anterior pituitary secretion of LH. Decreased LH causes the corpus luteum to
degenerate and menstruation to occur.
12. During menstruation, there is a low level of estrogen and progesterone in the
female body, causing the endometrial lining to disintegrate and pass out of the
vagina . During the proliferative phase of the uterine cycle, increased production
of progesterone causes the endometrium to thicken, become vascular and
glandular. Ovulation occurs on the fourteenth day of the twenty-eight-day cycle.
During the secretory phase, increased progesterone by the corpus luteum causes
the endometrium to double in thickness and uterine glands to produce a thick
mucoid secretion so that the endometrium can now receive the developing
embryo.
13. The placenta originates from both maternal and fetal tissues and is the region of
exchange of molecules between fetal and maternal blood. The placenta produces
HCG, which maintains the corpus luteum in the ovary until the placenta produces
its own estrogen/progesterone.
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14. The hormone estrogen is largely responsible for the secondary sex characteristics
in females, including body hair, fat distribution, enlarged pelvic girdle, and wider
hips. A female breast contains one or two dozen lobules, each with its own
mammary duct that opens at the nipple. Each mammary duct divides into other
ducts, which end in blind sacs called alveoli . Alveoli are made up of cells that
produce milk after pregnancy when the hormone prolactin is produced. After
delivery of a baby, the breasts first produce a watery, yellowish white fluid called
colostrum. During menopause, the ovarian and uterine cycles cease.
Control of Reproduction
Concepts:
- Birth-control measures vary in effectiveness from those that are very effective
to those that are minimally effective.
- There are alternative methods of reproduction today, including in vitro
fertilization followed by introduction to the uterus.
15. The most reliable method of birth control is abstinence, and has the added
advantage of preventing transmission of sexually transmitted disease. In the birthcontrol method called vasectomy, the vas deferens are cut and tied. Birth control
pills involve taking estrogen and progesterone, that shut down the pituitary
production of FSH and LH.
16. The diaphragm is a plastic cup that covers the cervix. Inhibin has been used to
prevent the anterior pituitary from production FSH. The contraceptive vaccine to
immunize women against HCG was successful to prevent implantation of the
embryo.
17. Morning - after regimens either prevent fertilization altogether or stop the
fertilized egg from ever implanting. RU-486 causes the loss of an implanted
embryo by blocking progesterone receptors of the cells in the uterine lining.
18. The two major causes of infertility in females are blocked oviducts , possibly due
to pelvic inflammatory disease (PID), and failure to ovulate due to low body
weight. Endometriosis , the presence of uterine tissue outside the uterus,
particularly in the oviducts and on the abdominal organs, can contribute to
infertility. Infertility in males may be due to low sperm count and /or a large
proportion of abnormal sperm, due to disease, radiation, high testes temperature
or psychoactive drugs.
19. In artificial insemination by donor (AID), sperm, either from the women’s
husband or a complete stranger, are placed in the vagina by a physician. In
intrauterine insemination, (IUI), the donor’s sperm is placed in the uterus after
hormonal stimulation of the ovaries. During in vitro fertilization (IVG),
immature, isolated eggs and concentrated sperm from the male are added together
in laboratory glassware. Later, the embryos are inserted into the uterus of the
woman. During gamete intrafallopina transfer (GIFT), the eggs and sperm are
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placed in the oviducts immediately after they have been brought together. This
procedure saves time and money. Surrogate mothers are women paid to have
babies from sperm (or eggs) contributed from other individuals.
20. AIDS, genital herpes, and genital warts are viral sexually transmitted disease that
do not respond to antibiotics. Gonorrhea and chlamydia are treatable with
antibiotic therapy but not always promptly diagnosed. AIDS (acquired
immunodeficiency syndrome) is cause by a group of retroviruses known as HIV
(human immunodeficiency viruses). HIV attaches to a protein in the plasma
membrane called a CD4 receptor. Once inside the host cells, HIV uses an enzyme
called reverse transcriptase to make a DNA copy of its RNA genetic material.
The DNA copy integrated into a host chromosome and makes more viral RNA.
During an asympomatic carrier stage, there are usually no symptoms, yet the
person is highly infectious. Symptoms of pre-AIDS begins to appear several
months to several years after infection. The final stage of HIV infection is called
full-blown AIDS in which a person has a severe depletion of helper T
lymphocytes and /or has an opportunistic infection.
21. The drug AZT is used to treat AIDS because, as an analog, when reverse
transcriptase chooses AZT instead of the normal nucleotide, reverse transcription
stops. Another class of drugs called proteinase inhibitors block the action of
another viral enzyme called proteinase. The largest proportion of people with
AIDS are homosexual men, but the proportions attributed to intravenous drug
users and heterosexuals is rising. Essentially, HIV is spread by passing virusinfected T lymphocytes found in semen or in blood from one person to another.
Genital herpes is caused by the herpes simplex virus, type 2. After the ulcers heal,
the disease is only dormant, and blisters can reoccur repeatedly.
22. Genital warts are caused by the human papillomaviruses (HPVs), which are
sexually transmitted and are now associated with cancer of the cervix and other
tumours. Gonorrhea is caused by the bacterium Neisseria gonorrhoeae. In the
male, a typical symptom of gonorrhea is a thick, greenish yellow urethral
discharge 3-5 days after contact. In females, it may spread to the oviducts causing
pelvic inflammatory disease (PID).
23. Chlamydia is named for the bacterium Chlamydia trachomatis. Chlamydia
infections of the genitals are the most common cause of nongonococcal urethritis
(NGU). Syphilis is caused by a bacterium called Treponema pallidum and can be
treated with penicillin. During the primary stage of syphilis, a hard chancre
(ulcerated sore with hard edges) indicates the site of infection. During the
secondary stage, the victim breaks out in a rash that does not itch. During the
tertiary stage, syphilis may affect the cardiovascular and nervous systems.
OBJECTIVE QUESTIONS: Completion and Short answer.
1. Label the diagram of the male reproductive system.
Reproductive System Review Answers
Biol 12
a.
b.
c.
d.
e.
f.
Epididymis
bulbourethral (Cowper’s) Gland
rectum
seminal vesicles
urinary bladder
testicle
g. ureter
h. penis
i. Prostate gland
j. vas deferens
x – seminiferous tubules
y – interstitial cells
2. Trace the adventures of Speedy, the sperm cell, as he passes through the male
reproductive system and meets up with his one and only true love, Eggie (an egg
in the female reproductive tract.) Speedy was born in a hospital room called a
seminiferous tubule found in a much larger city called testicle. He quickly
outgrew his living arrangements and moved into another adjacent long tubular
room called the epididymus. There Speedy matured rapidly until he was pushed
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out into a muscular tube called the vas deferens and then into another short tube,
the ejaculatory duct in which he had a lot of nutrients to eat. His stay was very
brief, and in the urethra, more fluid was added in which he found himself
suddenly able to wiggle his tail. With a sudden gush, he was thrust into a new
environment with much more room to swim about, called the vagina. As Speedy
passed through a tiny opening, the cervix, he found himself in an even larger
room, called the uterus , which had two openings in the distance. Speedy chose
the left opening and found himself struggling to swim against the opposite
movement of tiny structures called cilia in a tube known as the oviduct (Fallopian
tube). However, Speedy could sense that his true love was just around the corner,
but he was disappointed to find Eggie completely covered by follicle cells.
However, Speedy was able to rescue his love by releasing enzymes from his hat
that he brought along, called the acrosome. True love knows no bound.
3. The hypothalamus secretes a hormone called gonadotropic releasing hormone
that stimulates the anterior pituitary to produce two hormones. The first, called
follicle stimulating hormone, promotes sperm formation in the seminiferous
tubules of the testes. The second hormone released from the anterior pituitary is
called luteinizing hormone, also known as interstitial cell-stimulating hormone,
and it stimulates the interstitial cells, found between the seminiferous tubules, to
produce testotsterone. This hormone is necessary for the maturation of sperm and
secondary sexual characteristics. Testosterone and inhibin exert negative feedback
control over the hypothalamus and anterior pituitary.
4. Label the following diagram of the female reproductive, urinary and digestive
tract organs.
a.
b.
c.
d.
e.
f.
oviduct (Fallopian tube)
rectum
ovary
cervix
urinary bladder
anus
g. uterus
h. urethra
i. vagina
j. clitoris
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Reproductive System Review Answers
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5. Label this diagram to illustrate the hormonal control of the ovaries by using the
following terms: progesterone, LH, FSH, GnRH, and estrogen
a. GnRH
d. estrogen
b. FSH
e. progesterone
c. LH
6. The urethra in the male carries urine and semen, but in the female, the urethra
carries only urine.
Answer: T
Restatement:
7. During the male refractory period, erection can be brought about by stimulation.
Answer: F
Restatement:
cannot!
8. During pregnancy, estrogen and progesterone are first produced by the ovary and
later by the placenta.
Answer: T
Restatement:
9. Spermatogenesis occurs in the interstitial cells, whereas testosterone production
occurs in the seminiferous tubules.
Answer: F
Restatement: switch spermatogenesis with testosterone production
10. Most of the sperm released during ejaculation will reach the egg for possible
fertilization.
Answer: F
Restatement: Very few sperm reach the egg
11. During the follicular phase of the ovarian cycle, LH stimulates the corpus luteum
to produce progesterone.
Biol 12
Answer: F
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Reproductive System Review Answers
Restatement: that occurs during the luteal phase
For questions 12-19, match the following parts of the male reproductive system to
each of the functions below.
a. testes
e. prostate gland
b. epididymides
f. urethra
c. vas deferens
g. bulbourethral
d. seminal vesicles h. penis
12. organ of copulation
h
13. provides nutrients in semen for sperm
e
14. conducts sperm and urine
f
15. conducts and stores sperm
c
16. maturation and some sperm storage
b
17. produces sperm and sex hormones
a
18. fluid increases sperm motility
e.
19. fluid allows for lubrication
g.
For questions 20-26, match the following hormones of the male reproductive system
to each of the sites and functions below.
a. GnRH
d. testosterone
b. FSH
e. inhibin
c. LH (ICSH)
20. stimulates seminiferous tubules in testes
21. stimulates interstitial cells in testes
22. made in seminiferous tubules, inhibits GnRH and FSH and LH
23. made by interstitial cells, regulates hypothalamus and anterior pituitary
24. made in anterior pituitary, regulates spermatogenesis
25. made in anterior pituitary, regulates testosterone
26. made in hypothalamus, regulates FSH and LH production
FSH
LH
inhibin
testost.
FSH
LH
GnRH
For questions 27-36, match the following parts of the female reproductive system
to each of the statements below.
a. ovaries
f. fimbriae
b. oviducts
g. clitoris
c. uterus
h. vulva
d. cervix
i. Labia majora
e. vagina
j. labia minora
27. opening of uterus into vagina
d.
28. finger-like projections of oviduct
f.
29. collective term for female external genitals
h
30. site for normal fetal development
c
31. external folds of skin
i
32. site of fertilization
b
33. surrounds the vaginal orifice
j
34. produces eggs and sex hormones
a
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Reproductive System Review Answers
35. organ homologous to the penis
g
36. birth canal
e
For questions 37 – 42, match the following terms to each of the statements below.
a. areola
d. milk
b. alveoli
e. menopause
c. colostrums
f. endometriosis
37. Fluid first produced several days after delivery
38. functional unit of breasts that produce milk
39. requires prolactin production
40. flow of endometrium into abdominal cavity
41. pigmented area surrounding the nipple
42. ovaries unresponsive to gonadotropic hormones
c
b.
d.
f.
a
e
For questions 43-47, match the following alternative methods of reproduction to each
of the statements below.
a. artificial insemination by donor
b. intrauterine insemination
c. in vitro fertilization
d. gamete intra-fallopian transfer
e. surrogate mothers
43. donor’s sperm placed in uterus
44. eggs and sperm placed together in oviducts
45. donor’s sperm placed in vagina
46. woman paid to receive sperm and/or eggs
47. eggs combine with sperm in laboratory glassware
b
d
a
e
c
For questions 48 – 60, match the following phases (events) in the female to each of
the statements below. Some terms may be used more than once.
a. ovarian cycle
e. menstruation
b. uterine cycle
f. proliferative phase
c. follicular phase
g. secretory phase
d. luteal phase
h. ovulation
48. an LH surge occurs prior to this event
49. low levels of estrogen and progesterone cause this event
50. increased levels of estrogen cause this phase
51. endometrium doubles in thickness, produces thick mucoid secretion
52. menses, proliferative, and secretory phases
53. follicular and luteal phases
54. endometrium breaks down, passes out vagina
55. increased levels of FSH cause this phase
56. increased levels of progesterone cause this phase
57. increased levels of LH cause this phase
58. increased levels of estrogen inhibit this phase
h
e
f
g
b
a
e
c
g
d
c
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Reproductive System Review Answers
59. increased levels of progesterone inhibit this phase
60. corpus luteum increases during this phase
d
d
Multiple Choice Questions
61. During circumcision, the
a. prostrate gland
b. seminal vesicle
c. foreskin
is surgically removed
d. vas deferens
e. epididymis
62. Which part of the sperm contains enzymes used to penetrate the egg?
a. acrosome b. nucleus
c. head
d. middle piece
e. tail
63. Which of the following hormones brings about secondary sexual characteristics in
a male?
a. GnRH
b. FSH
c. ICSH
d. inhibin
e. testosterone
64. The hormones estrogen and FSH are produced by
and
respectively.
a. testes, hypothalamus
d. ovary, hypothalamus
b. ovary, anterior pituitary
e. hypothalamus, ovary
c. anterior pituitary, ovary
,
65. The placenta originate from
tissues.
a. maternal and fetal
d. only maternal
b. paternal and fetal
e. only paternal
c. only fetal
66. What hormone is produced from the placenta to maintain the corpus luteum
during pregnancy?
a. estrogen
b. progesterone
c. LH d. FSH
e. HCG
67. During pregnancy, which of the following statements is NOT true about high
amounts of estrogen and progesterone?
a. the anterior pituitary is shut down.
b. FSH and LH secretion is inhibited
c. The uterine lining is maintained
d. The endometrium is degraded
68.
occurs when the penis fails to become erect.
a. circumcision
d. Hysterectomy
b. sterilization
e. Menopause
c. Impotency
69. The
cells support, nourish, and regulate spermatogenic cells within the testes.
a. Sertoli
b. spermatid c. interstitial d. follicle
e. corpus luteum
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70. Which of the following is NOT a function of testosterone?
a. maturation of sperm
b. maturation of eggs
c. beard growth
d. enlargement of larynx and vocal cords
e. largely responsible for acne and body odour
71. Which of the following is NOT a function of estrogen?
a. development of endometrium
b. formation of body hair
c. distribution of fat for rounded appearance
d. smaller pelvic girdle
e. breast development
72.
are most numerous in the ovary at birth
a. Sertoli cells
d. Secondary follicles
b. corpus luteum
e. Primary follicles
c. Graafian Follicles
73. Which of the following will burst to release the egg into the oviduct?
a. Sertoli cells
d. Secondary follicles
b. corpus luteum
e. Primary follicles
c. Graafian Follicles
74. Which sexually transmitted disease is classified as a retrovirus?
a. AIDS
d. gonorrhea
b. genital herpes
e. chlamydia
c. genital warts
75. Which sexually transmitted disease is due to a papillomavirus?
a. AIDS
d. gonorrhea
b. genital herpes
e. chlamydia
c. genital warts
Subjective Question.
76. Infertility can sometimes be corrected, if there is no oviduct obstruction and the
body weight is normal, by giving females HCG, extracted from the urine of
pregnant women, along with gonadotropins extracted from the urine of
postmenopausal women. Explain the rationale for obtaining each of these
hormones from the urine of pregnant and postmenopausal women.
HCG is in high amounts in pregnant women since it is secreted from the placenta and
is used to maintain the corpus luteum in the ovary to produce estrogen and
progesterone. Postmenopausal women lack estrogen and progesterone in their urine
since the ovary is no longer functioning. Therefore, the gonadotropic hormones FSH
and LH will be easier to obtain from the urine since they are still being produced
from the anterior pituitary but the receptors on the ovary are not able to use them.