Sexual reproduction entails the union of two gonads to form a zygote.
False
Males produce sperm and females produce eggs.
True
The presence of the Y chromosome guarantees the development of male secondary sex organs.
False
The mechanism that keeps the testes cooler than the body's core temperature is called descent of the testes.
False
The scrotum contains the testes and spermatic cords.
True
Sperm travels to the ampulla of the ductus deferens before reaching the spermatic cord.
False
Nurse cells secrete inhibin, which regulates the rate of sperm production.
True
Testosterone stimulates development of the secondary sex characteristics, spermatogenesis, and libido.
True
Erectile dysfunction prevents ejaculation in most cases.
False
At early puberty, follicle stimulating hormone (FSH) and luteinizing hormone (LH) stimulate enlargement of the testes.
True
Spermiogenesis is the last stage of meiosis.
False
Sperm make up just 10% of semen volume.
True
Only germ cells undergo meiosis, which produces four haploid (n) cells with 23 chromosomes each.
True
Sympathetic nerve fibers trigger the secretion of nitric oxide, which dialtes the deep arteries allowing
False
The first haploid (n) stage of spermatogenesis is prophase II.
True
Myotonia of skeletal muscles is characteristics of the excitement phase and refractory period.
False
Which of the following is generally accepted as a secondary sex characteristic?
The enlargement of the breasts
Which of the following are female primary sex characteristics?
Ovaries
Which of the following is a female secondary sex organ?
Vagina
Gonads begin to develop _________ weeks after fertilization.
5 to 6
Whether an orgasm will be genetically male or female is determines by
the sperm
The gene that codes for the testis-determining factor (TDF) is found in or on the
Y chromosome
The penis is homologous to the
clitoris
The _________ is the gonad and the _________ is the gamete.
testis; sperm
Descent of the testes is stimulated by the
presence of testosterone
The _________ is an example of the female external genitalia.
clitoris
The __________ is the small, bilateral organ found lateral to the membranous urethra.
bulbourethral land
The golf-ball sized structure found inferior to the urinary bladder, and surrounding the most proximal portion of the urethra, is called the
prostate
The __________ is the site of sperm maturation and storage.
epididymis
The deep region of the penis, surrounding the urethra, that engorges with blood during an erection is known as the
corpus spongiosum
Which of the following is the correct pathway of sperm cells from their formation to ejaculation?
Seminiferous tubule, rete testis, epididymis, ejaculatory duct, urethra, ductus deferens
When it is cold, the _________ contracts and draws the testes closer to the closer to the body to keep them warm.
cremaster
The countercurrent heat exchanger that prevents arterial blood from overheating the testes is the
pampiniform plexus of veins
Which of the following is true regarding the blood-testis barrier?
It prevents antibodies in the blood from getting to the germ cells.
By volume, most of the semen is produced in the
seminal vesicles
Which of the are not found in or around the seminiferous tubules?
Corpus cavernosum cells
The penile urethra is enclosed by the
corpus spongiosum
Men have only one
prostate
Why would an enlarged prostate interfere with urination?
It compresses the urethra
The penis is innervated by the _________ nerve.
internal pudendal
Which of the following does not play a role in thermoregulation of the testes?
The bulbosponiosus muscle
When do the testes start secreting testosterone?
In the first trimester of fetal development
Which of the following hormones directly stimulates the development of male secondary sex characteristics?
Testosterone
Which of the following is an androgen?
Testosterone
__________ stimulates the interstitial cells of the testes to secrete __________.
Luteinizing hormone (LH); testosterone
Which hormone suppresses spermatogenesis without affecting testosterone secretion?
Inhibin
The _________ has/have no androgen receptors and do/does not respond to it.
germ cells
Which of the following is inhibited by testosterone?
Gonadotropin-releasing hormone (GnRH) secretion
Changes called male climacteric are a consequence of a(n)
decreased secretions of testosterone
The haploid (n) result meiosis I is called a
secondary spermatocyte
In the process of spermiogenesis, __________ become ___________ .
spermatids; spermatozoa
In meiosis, each parent cell produces
four haploid (n) cells
The process of spermatogenesis begins with a __________ and ends with four __________.
germ cell; gametes
At the end of meiosis I there are _________, whereas at the end of meiosis II there is/are __________.
two haploid (n) cells; four haploid (n) cells
Which of the following is the most important role of meiosis in sexual reproduction?
It prevents the chromosome number from doubling in each generation.
At what stage does a developing sperm cell begin to grow a tail?
Spermatid
Sperm cells get energy to power their movement from _________, which is contributed by the __________.
fructose; seminal vesicles
Male infertility (sterility) refers to
the inability to fertilize an egg
The acrosome contains enzymes used to
penetrate barriers surrounding the ovum
_________ have 46 chromosomes, whereas __________ have 23.
Primary spermatocytes; spermatids
A sperm count any lower than _________ million sperm per mL of semen is usually associated with infertility (sterility).
20 to 25
Dilation of the _________ causes the lacunae to fill with blood and the penis to become erect.
deep arteries
The orgasm-emission phase of the male sexual response is stimulated by
efferent sympathetic signals from the lumbar region of the spinal cord
Which of the following explains the neural mechanism of an erection?
It is an autonomic reflex mediated predominantly by parasympathetic nerve fibers
Heart rate, blood pressure, and respiratory rate peak during the
climax (orgasm)
Sildenafil (Viagra) prolongs erection by
inhibiting degradation of cGMP
Which of the following are changes in the male body that results from puberty?
Deepening of the voice, gain in muscle mass, growth of the scrotum and penis, acne
Which of the following is not a function of the nurse cells?
They secrete testosterone
Genetic males are XY and genetic females are XX.
True
In the female fetus, the absence of testosterone results in the development of the external genitalia into clitoris, labia minora, and labia majora.
True
The uterus is a thick muscular chamber inferior to the urinary bladder.
False
The vagina has no glands but it is moistened by mucus from glands in the cervical canal.
True
Although two breast cancer genes are known, most cases are nonhereditary.
True
Inhibin modulates the secretion of LH.
False
The number of ovarian follicles declines with age, leading to a reduction of estrogen levels.
True
The ovarian cycle typically lasts about 28 days, with day 1 considered to be the first day ovulation.
False
Most primary oocytes undergo atresia during climacteric.
False
The proliferative phase of the uterus is driven by estrogen from the ovaries.
True
In the excitement phase, the uterus rises from its forward-tilted (anteverted) position.
True
Unlike men, women lack a refractory period and may experience successive orgasms.
True
Human chorionic gonadotroping (HCG) stimulates the corpus luteum to grow and secrete estrogen and progesterone.
True
Progesterone stimulates uterine contractions.
False
Prolactin is secreted during pregnancy to stimulate milk synthesis so that milk will be available by the time the infant is born.
False
Oxytocin stimulates contraction of myoepithelial cell of the mammary acini.
True
Which of the following is a part of the internal female genitalia?
Vagina
In which structure does fertilization usually occur?
Uterine tube
Which of the following structures is composed of a theca folliculi, granulosa cells, a zona pellucida, and a secondary oocyte?
Secondary follicle
What structure leads from each ovary to the uterus?
Uterine tube
Which uterine layer is composed of a simple columnar epithelium containing tubular glands?
Endometrium
Which of the following is not a component of the vulva?
Cervix
In the prementrual phase of the menstrual cycle, which arteries rhythmically constrict and dilate causing endometrial ischemia?
Spiral
After puberty, which epithelium lines the vagina?
Stratified squamous epithelium
Where does an embryo usually attach to its mother?
To the endometrium
What provides most of the natural lubrication during female sexual excitement?
Greater vestibular glands
The nonpregnant uterine wall consists mostly of
myometrium
Which of these is not found in the vestibule?
Mons pubis
__________ are found in both male and female external genitalia, but the __________ is/are only found in the female.
Corpora cavernosa; vestibular bulbs
When do mammary glands primarily develop within the breasts?
During pregnancy
What determines breast size?
The amount of adipose tissue
Where are follicles located?
Cortex of the ovary
What is the earliest sign of puberty in girls?
The onset of breast development
Which of the following is considered a "feminizing hormone"?
Estrogen
Which hormone acts primarily on the uterus?
Progesterone
The appearance of pubic and axillary hair is characteristic of which stage of puberty?
Pubarche
What is the midlife change in estrogen and progesterone levels referred to as?
Climacteric
What is the cessation of menstruation referred to as?
Menopause
During climacteric, what can cause hot flashes?
Vasodilation of cutaneous arteries
What does the term "menstrual cycle" specifically refer to?
The cyclic changes in the uterus determined by shifting hormonal changes
What is an ovulated egg more technically referred to as?
A secondary oocyte
Which stage of meiosis is an ovulated egg in?
Metaphase II
When does an ovum finish meiosis?
During fertilization
Most ovulation home test kits measure a surge of which hormone?
LH
In ovulation, after expelling the oocyte the follicle becomes a _________ and secretes __________.
corpus luteum; estrogen and progesterone
What is a follicle composed of?
An oocyte enclosed in follicular or granulosa cells
Which follicle stage is characterized by the development of a corona radiata?
Tertiary
When does oogenesis begin?
During embryonic development
In the adult ovary, more than 90% of the follicles are found as
Primordial follicles
During the follicular phase, granulosa cells secrete _________, which stimulates secretion of _________.
estradiol; LH
Which of these blood hormone levels reaches its maximum during the luteal phase?
Progesterone
What hormone(s) inhibit(s) the secretion of FSH and LH during the female sexual cycle?
Estradiol and progesterone
What do lutein cells develop from?
The theca interna
Which phase of the mentrual cycle is the one associated with menstrual cramps?
Premenstrual
Which of the following occurs during the proliferative phase of the menstrual cycle?
Several follicles are developing an antrum
The ________ sometimes expels copious fluid similar to prostatic fluid, which constitutes the female ejaculate.
paraurethral glands
During the plateau phase of the sexual response, the glans and clitoris swell as the deep arteries dilate and the ________ engorge with blood.
corpora cavernosa
In early pregnancy, what hormone stimulates growth of the corpus luteum?
Human chorionic gonadotropin
During ________, the uterus is tented (erected) and the cervix is withdrawn from the vagina. Typically, the clitoris is engorged and the labia are bright red to violet due to hyperemia.
excitement
Pregnancy kits test for the presence of what hormone?
Human chorionic gonadotropin
Between weeks 3 and 8 of development, a developing individual is considered a(n)
embryo
Contraceptive pills mimic the ________ feedback effect of ________.
negative; estrogens and progesterone
Which form of estrogen is the most potent in pregnancy?
Estradiol
Which of the following provides fetal nutrition and secretes hormones that regulate pregnancy and fetal development?
The placenta
What is the longest stage of labor?
The dilation stage
Milk ejection occurs as a result of stimulation of nerve endings in the ________, which leads to the release of ________from the pituitary.
nipple and areola; oxytocin
Why is breast milk superior to cow's milk for an infant?
Cow's milk has too much protein and minerals in it.
What is the infant's only source of nutrition during the first 2-3 days postpartum?
Colostrum
The medial pole of the ovary is attached to the uterus by which ligament?
Ovarian ligament
The anterior margin of the ovary is anchored by a peritoneal fold called the
mesovarium
The ovary receives blood from which artery/arteries?
Ovarian and uterine
During climacteric, women secrete
less estrogen and progesterone
Which of the following is true of the female sexual response?
Women do not have a refractory period and may quickly experience additional orgasms.
Why do pregnant women often have heartburn?
As the uterus enlarges it pushes upward on the stomach, causing gastric reflux.
Women with morning sickness tend to prefer spicy and pungent foods.
False
"False labor" is result of what type of contractions?
Braxton Hicks
When an infant suckles at its mother's breast, milk moves through the breast structures in what order?
Acinus > lactiferous duct > lactiferous sinus > nipple
How is colostrum different than breast milk?
It has one-third less fat.
Which of the following is not a benefit of breast feeding?
It prevents colonization of the neonatal intestine with beneficial bacteria.
Sperm must travel to the distal end of the uterine tube to encounter the egg before it dies.
True
The slow block referes to the mechanism that prevents fertilization of another egg when one is already pregnant.
False
The fertilization membrane is the endometrial tissue that receives the conceptus.
False
Cleavage results in daughter cells containing half the number of chromosomes of the parent cell.
False
During implantation, the embryoblast undergoes gastrulation.
True
The embryonic stage extends from 16 days through the end of week 8.
True
The chorion forms the fetal part of the placenta.
True
The placenta begins to form after week 8.
False
Trophoblastic nutrition refers to the nutrition of the conceptus before it implants.
False
Neonatal immunity depends on IgG and IgA acquired through the placenta and colostrum, respectively.
True
To some extent, the heat loss of the neonate is compensated for by the thermal insulation provided by brown fat.
False
Inadequate liver function is the most common reason that premature infants suffer from multiple dysfunctions.
True
Teratogens usually do not cause congenital anomalies.
False
Senescence begins different ages and progresses at different rates in different organ systems.
True
Life expectancy has steadily increased in the last century, whereas life span has not.
True
A person in his or her 90's can increase muscle strength by two or three times with 40 minutes of isometric exercise per week.
True
Which of the following lists the stages or structures of prenatal development in the correct order?
Zygote, cleavage, morula, blastocyst, embryo, fetus
The process that makes it possible for sperm to penetrate the eggs is called
capacitation
In the slow block to polyspermy, sperm penetration release an inflow of _________, which in turn stimulates the __________.
Ca2+; cortical reaction
In the fast block to polyspermy, binding of sperm opens up __________ channels, which depolarizes the egg membrane and __________.
Na+; prevents the entrance of any more sperm
Regarding fertilization, which of the following events happens first?
The acrosomal reaction
The optimal "window of opportunity" to conceive a child is
a few days before ovulation to less than a day after
The spheroidal stage of early prenatal development with about 16 to 64 cells is called a(n)
morula
Twins produced when a single egg is fertilized are called __________ twins. Twins produced from two eggs ovulated at the same time are called _________ twins.
monozygotic; dizygotic
In the blastocyst, the trophoblast will become________, whereas the embryoblast will become __________.
part of the placenta; the embryo
Primary germ layers are formed during
gastrulation
Mesenchyme gives rise to _________.
muscle, bone, and blood
During implantation, the trophoblast divides into a deep layer called the ________, which is composed of individual cells.
cytotrophoblast
By the time the conceptus arrives in the uterus, it consists of at least ________ or more cells.
16
During implantation, the trophoblast divides into a superficial layer called the ________, which is composed of a multinucleate mass of cytoplasm.
syncytriotrophoblast
Out of the 300 million ejaculated sperm, only about ________ reach the vicinity of the egg.
200 to 300
Prior to ejaculation, __________ in the plasma membrane of the sperm prevents premature release of __________.
cholesterol; acrosomal enzymes
Which of the following is not a derivative of ectoderm?
The dermis
The first body cavity is called the
coelom
By the end of 8 weeks, the individual is considered a fetus because
all of the organ systems are present
The __________ completely encloses the embryo and provides it with a stable environment.
amnion
The _________ encloses all the rest of the membranes and the embryo.
chorion
The _________ is an embryonic membrane that serves as the origin of the first blood and germ cells.
yolk sac
As it implants, the concepts is nourished by means of
trophoblastic nutrition
The ________ begins to develop about 11 days after conception, and is the sole source of fetal nutrition from the end of week 12 until birth.
placenta
In fetal circulation, the ________ bypasses the liver and the _________ bypasses the lungs.
ductus venosus; ductus arteriosus
In fetal circulation, blood bypasses the lung by flowing through the
foramen ovale and ductus arteriosus
Which of the following major events of prenatal development happens first?
The central nervous system begins to form
Oxygenated blood reaches the fetus through the
umbilical vein
Which of the following is not considered an embryonic membrane?
Placenta
________ pass(es) from the maternal blood to the fetal blood. Fetal ________ pass(es) the other way.
Oxygen and nutrients; wastes
The digital rays of a fetus give rise to
fingers and toes
The first 6 weeks of postpartum life constitute the _______ period.
neonatal
The fossa ovalis is a remnant of the ________ of the fetus.
foramen ovale
During birth, an infant is normally stimulated to breathe by
CO2 accumulating in the baby's blood
Which of the following organ systems shows the greatest anatomical change in the transitional period after birth?
Circulatory system
Infant respiratory distress syndrome (IRDS) is caused by
deficiency of pulmonary surfactant
Which of the following organ systems faces the greatness physiological challenge in the transitional period after birth?
Respiratory system
A teratogen is most likely to cause
a deformity of the limbs
Which of the following does not have potentially teratogenic effects?
Sunlight
Down syndrome (trisomy-21) results from
nondisjunction
The most likely outcome of nondisjunction is the production of a gamete receiving
22 chromosomes
Only autosomal trisomes involving chromosomes 13, 18, and 21 are survivable. Why would this be?
These are relatively gene-poor chromosomes
Urine retention is a greater problem for elderly men than for elderly women because men
can develop benign prostatic hyperplasia
Which of the following is not a reason muscular weakness tends to develop in old age?
The myocytes of aged muscle no longer synthesize myosin.
Older people may require lower drug doses than younger people because
they have lower rates of renal clearance
Which of the following statements is true regarding telomeres?
Telomeres are DNA segments at each end of a chromosome.
The observation that there is a limit to how many times a cell can divide is the basis for the ________ theory of senescence.
replicative
Which of the following systems shows the least overall senescence?
Endocrine system
Senescence of the immune system makes older people more susceptible to cancer and infectious disease because of a decline in
antigen-presenting cells and helper T cells
Which of the following is not a known benefit of regular exercise?
Prolonged life expectancy
Which of the following is not a known cause of congenital anomalies?
Smoking during lactation
The fetus deposits fat in its subcutaneous tissue in the 7th month of gestation.
True