Chapter 27-The Reproductive System
During meiosis, what does crossover promote?
Crossover promotes increased genetic variability among gametes.
Which of the following statements about sperm is not true?
They are sluggish in an alkaline environment.
How do the testes respond to exposure to excessive body warmth?
They move away from the pelvic cavity.
A scrotal muscle that contracts in response to cold environmental temperature is the cremaster.
True
Both tetrads and crossovers are seen during meiosis.
True
Dehydroepiandrosterone (DHEA) is the main androgen that is associated with female libido.
True
Failure to attain erection is called erectile dysfunction.
True
Gametes are produced by meiosis.
True
It is necessary for the testes to be kept below body temperature for abundant, viable sperm formation.
True
Sexually transmitted diseases are an important cause of female fertility problems.
True
Sperm from the male parent determines the gender of the child.
True
The first sign of puberty in females is budding breasts.
True
The mammary glands are present in both sexes.
True
The ovaries are situated in the peritoneal cavity flanking the uterus.
True
The soft mucosal lining of the uterus is the endometrium.
True
When a couple is having difficulty conceiving a child, it is necessary to investigate the sperm of the male.
True
If embryonic testes do not produce testosterone, a genetic male develops female external genitalia. However, if embryonic testes properly produce testosterone, but a genetic male nevertheless develops female external genitalia, the cause could be ______.
a mutation in the gene that codes for the testosterone receptor
Erection of the penis results from ________.
a parasympathetic reflex
Enzymes that allow sperm to penetrate the egg are located in the __________ of the sperm cell.
acrosome
What part of the breast produces milk?
alveoli
Which of the following keeps the concentration of testosterone in the vicinity of the spermatogenic cells high to stimulate spermatogenesis?
androgen-binding protein (ABP)
Amenorrhea can occur in women engaged in extremely strenuous physical activity, and also occurs in women who ______.
are pregnant
What is the pigmented ring of skin situated slightly below the center of each breast?
areola
The __________ connects the uterus to the vagina.
cervix
Which structure of the female's external genitalia has erectile tissue like the penis?
clitoris
Which is not a part of the proliferative phase of the female menstrual cycle?
corpus luteum
The duct system of the male reproductive system does not include the ________.
corpus spongiosum
A surge in __________ directly triggers ovulation.
luteinizing hormone (LH)
What hormone promotes ovulation?
luteinizing hormone (LH)
Which specific layer of the uterus is shed during menstruation, approximately every 28 days?
stratum functionalis of the endometrium
The __________, a layer of the endometrium, is shed during each menstruation and is then regenerated by the __________.
stratum functionalis; stratum basalis
The testicular cells that construct the blood-testis barrier are the ________.
sustenocytes
Which of the following is the site where sperm are stored until they are ejaculated?
tail of the epididymis
Which of the following is housed within the spermatic cord?
testicular arteries and veins
During the secretory phase of the uterine cycle __________.
the endometrium prepares for implantation
Formation of a secondary oocyte occurs during __________.
the follicular phase
Which of the following glands are responsible for about 70% of the volume of semen?
the seminal glands
What is the role of the corpus luteum?
to produce hormones that maintain the uterine lining during the first months of pregnancy
Which of the following statements about spermatogenesis is not true?
Each spermatid forms two sperm.
Select the correct statement about male sexual response.
Erection is the result of vascular spaces in the erectile tissues filling with blood.
All of the following statements referring to the uterine cycle are true except ________.
FSH and LH directly promote development of the uterine endometrium
A human egg or sperm contains 23 pairs of chromosomes.
False
Extremely stressful physical activity in young females can result in excessive bone mass due to large amounts of estrogen production.
False
Female orgasm is required for conception.
False
Ovarian follicles contain mature eggs.
False
Ovulation occurs near the end of the ovarian cycle.
False
Pain during ovulation is called dysmenorrhea.
False
Sperm are ejaculated from the corpora cavernosa of the penis.
False
The adenohypophyseal hormone that triggers ovulation is estrogen.
False
The amount of testosterone and sperm produced by the testes is dependent on the influence of FSH alone.
False
The corpus luteum secretes progesterone only.
False
The male urethra serves the urinary system only.
False
The molecule that enhances the ability of testosterone to promote spermatogenesis is inhibin.
False
The primary function of the testes is to produce testosterone.
False
The prostate atrophies as a man ages, and it usually causes no health problems.
False
The stage in meiosis where chromosomal exchange takes place is telophase.
False
The testes are innervated by the sympathetic division of the ANS only.
False
The testis is divided into seminiferous tubules which contain the lobules that produce sperm and the ejaculatory duct that allows the sperm to be ejected from the body.
False
Viable sperm production is optimal at the body's core temperature.
False
When it is cold, the scrotum is pulled away from the body.
False
Which of the following hormones stimulates the release of anterior pituitary gonadotropins?
GnRH
Select the correct statement about testosterone control.
GnRH from the hypothalamus causes FSH and LH release from the anterior pituitary.
Select the correct statement about the hormonal events of the ovarian cycle.
High estrogen levels result in a surge of LH release.
Select the correct statement about the uterine cycle.
If fertilization occurs, the corpus luteum is maintained by a hormone secreted by the developing embryo.
Why are the male testes located in the scrotum outside the body?
Immature sperm are temperature sensitive.
A 38-year-old male is upset about his low sperm count and visits a "practitioner" who commonly advertises his miracle cures of sterility. The practitioner is a quack who treats conditions of low sperm count with megadoses of testosterone. The patient experiences a huge surge in libido. Would this treatment result in a higher or lower sperm count, and why?
Lower sperm count. High levels of testosterone inhibit the release of GnRH, inhibiting FSH release, resulting in direct inhibition of spermatogenesis.
Why CAN'T polar bodies be fertilized?
Polar bodies lack nutrient-containing cytoplasm.
Which of these statements about sexually transmitted infections is false?
Syphilis is caused by a virus that may lead to death if untreated.
Which of the following will occur after ovulation?
The endometrium enters its secretory phase.
Occasionally three polar bodies are found clinging to the mature ovum. One came from an unequal division of the ovum, but from where did the other two arise?
The first polar body has also divided to produce two polar bodies.
Which of the following is a correct statement about uterine tubes?
The infundibulum is the funnel-shaped region near the ovary.
Which of the following statements is true concerning the mammary glands of both males and females?
The mammary glands are modified sweat glands that are actually part of the integumentary system.
Which of the following is FALSE regarding the vagina of an adult female?
The pH of the adult vagina is alkaline.
Why doesn't semen enter the urinary bladder during ejaculation?
The smooth muscle sphincter at the base of the urinary bladder closes.
Why does only one egg, rather than four eggs, develop during oogenesis, given that spermatogenesis results in four sperm formed from one stem cell?
The unequal cytoplasmic division that results in one egg and three polar bodies ensures that a fertilized egg has ample nutrients for its journey to the uterus.
The dartos and cremaster muscles are important to the integrity of the male reproductive system. Which of the following is true about the role they play?
They regulate the temperature of the testes.
Oocytes only complete meiosis II if they are fertilized.
True
The Pap smear is a test to detect cancerous changes in cells of the cervix.
True
The secretions of the bulbo-urethral glands neutralize traces of acidic urine in the urethra and serve as a lubricant during sexual intercourse.
True
The smaller cell produced by oogenesis meiosis I, called the first polar body, is essentially a packet of discarded nuclear material.
True
The zona pellucida is formed as the follicle becomes a secondary follicle.
True
A boy who has not passed through puberty sustains an injury to his anterior pituitary such that FSH is no longer released, but LH is normal. After he grows to maturity, one would expect that he would ________.
be sterile
Why is the blood testis barrier important?
because spermatozoa and developing cells produce surface antigens that are recognized as foreign by the immune system
Normally menstruation occurs when ________.
blood levels of estrogen and progesterone decrease
Which of the following conditions might contribute to an increased probability of having an ectopic pregnancy?
decreased number of cilia in the uterine tubes
A low secretion of luteinizing hormone (LH) in the normal male adult would cause ________.
decreased testosterone secretion
A varicocele may hinder blood flow through the pampiniform venous plexus; the reduced venous drainage and the resulting elevated testicular temperature may be caused by ______.
defective venous valves in the testis
During vasectomy, what accessory duct is cut as a form of birth control?
ductus (vas) deferens
Sperm are stored in the __________.
epididymis
Which of the following female sex hormones is most responsible for estrogenic effects?
estradiol
Spermiogenesis involves the ________.
formation of a functional sperm by the stripping away of superfluous cytoplasm
What is the product of spermatogenesis?
formation of haploid spermatozoa
Which of the following is NOT a sexually transmitted bacterial disease?
genital herpes
Effects of estrogen include ________.
growth of the breasts at puberty
In humans, separation of the cells at the two-cell state following fertilization may lead to the production of twins, which in this case would be ________.
identical
The basic difference between spermatogenesis and oogenesis is that ________.
in oogenesis, one mature ovum is produced, and in spermatogenesis four mature sperm are produced from the parent cell
Which male hormone inhibits the secretion of FSH?
inhibin
Which of the following inhibits the release of FSH from the anterior pituitary and GnRH from the hypothalamus when the sperm count is high?
inhibin
The mammary glands belong to which of the following systems?
integumentary system
Which cells produce androgens such as testosterone?
interstitial endocrine (Leydig) cells
The cells that produce testosterone in the testis are called ________.
interstitial endocrine cells
The brain-testicular axis ________.
involves FSH and LH release
Spermatogenesis ________.
involves a kind of cell division limited to the gametes
What are the two fatty, hair-covered skin folds that run posteriorly from the mons pubis?
labia majora
Which of the following female structures is homologous to the male scrotum?
labia majora
Specifically, what encloses the vestibule which houses the openings of the urethra and vagina?
labia minora
The cause of cryptorchidism is typically not understood, but one possible cause might be a narrowing of the inguinal canal. This narrowing could arise from encroachment by any EXCEPT which of the following muscles?
latissimus dorsi
The release of __________ encourages interstitial endocrine cells to release __________.
luteinizing hormone; testosterone
During what phase of the female's uterine (menstrual) cycle is the uterine lining shed?
menstrual phase
The __________ develop into the male duct system.
mesonephric ducts
The constancy of the chromosome number from one cell generation to the next is maintained through ________.
mitosis
Which layer of the uterine wall is made of smooth muscle?
myometrium
How many functional gametes are produced by oogenesis?
one functional gamete
Which of the following is considered a primary sex organ in females?
ovary
What event occurs during the proliferative phase?
ovulation
The ability of sperm cells to move along the ductus deferens is due to ________.
peristaltic contractions
Which of the following organs is NOT a part of the HPG axis?
posterior pituitary gland
Which portion of the penis is removed through a procedure known as circumcision?
prepuce (foreskin)
During the secretory phase of the menstrual cycle ________.
progesterone levels are at their highest
Which of the following is an effect of estrogen in females?
promotes oogenesis
At what point during meiosis do homologous chromosomes pair up?
prophase I
Genetic variation of individual chromosomes occurs during __________.
prophase I
The primary function of the uterus is to ________.
receive, retain, and nourish a fertilized ovum
If an untrained person induces an abortion and severely punctures the posterior vaginal wall, there is a potential risk of the puncture wound extending onward into the wall of the ______.
rectum
Which of the following phases or processes in the monthly reproductive cycle of the female occur simultaneously?
regression of the corpus luteum and a decrease in ovarian progesterone secretion
Although effective in treating erectile dysfunction, Viagra has the side effect of reducing systemic blood pressure by causing ______.
relaxation of muscle tissue in arteries
Which of the following cells is released during ovulation?
secondary oocyte
Which of the following is the haploid cell produced as a result of meiosis I?
secondary spermatocyte
Sperm is produced in the __________ of the testes.
seminiferous tubules
Which of the choices below is not a function of the vagina?
serves as a passageway for the primary oocyte
What determines the gender (sex) of a child?
sex chromosomes
Prostate cancer is _______.
sometimes a slow-growing cancer that may never represent a threat to the patient
Which of the following results from spermiogenesis?
sperm
Which of the following occurs during spermiogenesis?
sperm are produced
In cervical cancer, which cancer cells that cover the cervical tip are most likely to be abnormal?
squamous epithelial cells
Which of the choices below is not a function of testosterone?
stimulates mammary gland development
Which layer of the uterus is the site for implantation of a fertilized egg?
stratum functionalis of the endometrium
Which hormone promotes the formation of secondary sex characteristics such as the appearance of pubic, axillary, and facial hair, enhanced hair growth on the chest, and a deepening voice?
testosterone
Which of the choices below is not a part of the hypothalamic-pituitary-gonadal axis?
thalamus
The "master switch" for male reproductive development is ________.
the SRY gene
The ability of a male to ejaculate is due to the action of ________.
the bulbospongiosus muscles
Human egg and sperm are similar in that ________.
they have the same number of chromosomes
What is the function of the blood testis barrier?
to prevent activation of the immune system of the male against the developing sperm
If gametes were diploid like somatic cells, how many chromosomes would the zygote contain?
twice the diploid number, and with every succeeding generation, the chromosome number would continue to double and normal development could not occur
Which of the following cells is returned to the basal lamina to continue the pool of dividing germ cells?
type A daughter cell or spermatogonium
The most important risk for testicular cancer in young males is ________.
undescended testes
Which of the following does NOT add substances to seminal fluid?
urethra
Which of these male accessory ducts transports both sperm and urine?
urethra
What part of the female duct system is the usual site of fertilization of the ovulated oocyte?
uterine (fallopian) tube (oviduct)
Which of the following is an INCORRECT matching of female reproductive structures with their functions?
uterine tube/transport unfertilized ovum to uterus for removal from the body
Fertilization generally occurs in the ________.
uterine tubes
The structures that receive the ovulated oocyte, providing a site for fertilization, are called the ________.
uterine tubes
The number of chromosomes in a human gamete is __________; this is referred to as the __________ chromosome number.
23; haploid
A man who has had a successful orchiectomy may still be able to have children because ______.
All of the listed responses are correct.
Nondisjunction may occur due to ______.
All of the listed responses are correct.
Which of the following may aggravate the symptoms of a prolapsed uterus?
All of the listed responses are correct.
Which of the following occurs as a result of undescended testes?
Inadequate or nonviable sperm will be produced.
Which hormone is absolutely necessary for ovulation to occur?
LH
Why does meiosis involve two nuclear divisions rather than one, as in mitosis?
Meiosis reduces the chromosome number by half.
Which of the following statements about the female reproductive process is not true?
Rebuilding the endometrium is under the control of prolactin.
