Chapter 28
How long is the secondary oocyte viable and capable of being fertilized after it is ovulated?
12-24 hours
Implantation of the blastocyst begins __________ after ovulation.
6 to 7 days
The Apgar score range that indicates a healthy baby is __________.
8 to 10
Which of the following INCORRECTLY matches the primary germ layer with the formed structures?
All of the above are correct.
Which statement about maternal hormones during pregnancy is accurate?
Estrogen levels increase throughout gestation.
A pregnancy test involves antibodies that detect growth hormone (GH) levels in a woman's blood or urine.
False
A zygote is usually formed within the uterus.
False
Acrosomal enzymes trigger exocytosis of cortical granules in the cortical reaction.
False
By 72 hours after fertilization, the egg has divided into more than 160 cells and is called the morula.
False
Fertilization occurs while the egg is still in the ovarian follicle.
False
Human placental lactogen initiates labor.
False
Which of the following statements about the foramen ovale is FALSE?
It allows blood to pass directly from the right atrium into the left ventricle.
What is the function of the hormone hCG (human chorionic gonadotropin)?
It signals the corpus luteum to continue producing estrogen and progesterone to maintain the pregnancy.
A friend confides that she desires to have children but is having trouble conceiving. Which of the following is true regarding implantation?
Its is estimated that a minimum of two-thirds of all zygotes formed failed to implant by the end of the first week or spontaneously abort.
What role does oxytocin play in promoting labor?
Oxytocin stimulates the uterus to contract.
Which of the choices below occurs if implantation is successful?
The corpus luteum is maintained until the placenta takes over its hormone-producing functions.
Which of the following does NOT describe a function of trophoblast cells?
The inner layers of trophoblasts lose their plasma membranes and invade the endometrium.
A blastocyst is a hollow ball of cells, while the morula is a solid ball of cells,
True
A pregnant woman urinates more often than usual because the uterus compresses the bladder, her metabolic rate and blood volume are increases, and she must also dispose of fetal metabolic waste.
True
An episiotomy is an incision made to widen the vaginal orifice, aiding fetal expulsion.
True
By the end of the embryonic period, at 8 weeks, all the adult organ systems are recognizable.
True
Implantation begins six to seven days after ovulation.
True
Of the three germ layers, the mesoderm forms the most body parts.
True
The embryonic period last until the end of the eighth week.
True
The period from fertilization through week eight is called the embryonic period.
True
Which of the following does NOT prevent polyspermy?
a decrease in zonal inhibiting proteins
What is the name for the period of time that extends from the last menstrual period until birth, which is approximately 280 days?
a gestation period
Which extraembryonic membrane forms the structural base of the umbilical cord during embryonic development?
allantois
Which of these is the innermost (closest) structure that completely surrounds the embryo?
amnion
Drinking alcohol during pregnancy is ___________.
associated with microencephaly and intellectual disorders of the fetus.
The heart begins to beat in the developing offspring __________.
at about 3 ½ weeks
Which of the following implants in the mucosa of the endometrium?
blastocyst
Implantation is completed after the __________.
blastocyst is entirely surrounded by endometrium
Which of the following structures is/are formed from ectodermal tissues?
brain
How does the embryo obtain adequate nutrition after implantation but before the formation of the placenta?
by digesting endometrial cells Submit
The function of the ductus arteriosus is to __________.
bypass the pulmonary circuit
In the block to polyspermy, entry of the sperm's contents causes ________ levels in the oocyte's cytoplasm to rise, triggering the cortical reaction.
calcium ion
Once sperm are deposited into the vagina, the sperm's motility must be enhanced and they must be prepared to release hydrolytic enzymes from their acrosomes. What is this process called?
capacitation
The outermost extraembryonic membrane is the __________.
chorion
Which extra-embryonic membrane is formed from the trophoblast after implantation?
chorion
The disc-shaped placenta is formed from the __________.
chronic villi and the decidua basalis
After fertilization, the zygote goes through a rapid period of cell divisions called __________.
cleavage
Which of the following is the correct sequence of development from zygote to embryo?
cleavage, morula, blastocyst, gastrula
Prior to the let-down reflex, the mammary glands secrete a yellowish fluid called ________ that has less lactose than milk and almost no fat.
colostrum
Which of the following is the first barrier that must be penetrated by the sperm in order to fertilize an oocyte?
corona radiata
What reaction prevents more than one sperm from binding to an oocyte during fertilization?
cortical reaction
What structures ultimately form the placenta?
decidua basalis and chorionic villi Submit
Which of the following is NOT a common metabolic/physiological change that occurs in pregnant women?
decreased blood pressure
Which of the following is the longest stage of labor, lasting 6-12 hours or more?
dilation stage
Which sequence shows the correct order of the stages of labor?
dilation, expulsion, placental
Which of the following is NOT a correct matching for a fetal structure with what it becomes at birth?
ductus arteriosus-ligamentum teres
Which germ layer gives rise to the nervous system?
ectoderm
Which of the following germ layers becomes the skin?
ectoderm
An implantation that takes place in a site other than the uterus is called __________.
ectopic
The corpus luteum prevents loss of the implanted embryo through menstruation by secreting ________.
estrogens and progesterone
At what point is meiosis II completed for the female gamete?
fertilization
Which structure represents the remnants of the atrial fetal shunt?
fossa ovalis
Which of the following refers to the transfer of sperm and harvested oocytes together into the woman's uterine tubes in the hopes that fertilization will take place there?
gamete intrafallopian transfer (GIFT)
Which of the following is NOT one of the primary germ layers?
gastroderm
Primary germ layers are formed while the embryo is in the __________ stage of development.
gastrula
The presence of endoderm, ectoderm, and mesoderm is first seen in the _________ stage.
gastrula
The presence of endoderm, ectoderm, and mesoderm is first seen in the ___________ stage.
gastrula
The development of the primary germ layers is called __________.
gastrulation
Which of the following would be the best method for delaying the onset of labor?
giving the mother antiprostaglandin drugs
Which hormone is required to maintain the corpus luteum and prevent menstruation?
hCG
A urine test reveals a positive result for human chorionic gonadotropin (hCG). This indicates ________ was successful.
implantation
Which of the following factors is NOT considered to be a teratogen?
iron
The small blue circles in the figure just inside the oocyte membrane represent vesicles containing calcium ions that are spilled into the extracellular space to prevent polyspermy. When does this take place?
just after the sperm's head enters the oocyte membrane
As pregnancy continues, the increasing bulkiness of the anterior abdomen changes the woman's center of gravity, possibly causing an accentuated lumbar curvature called ________.
lordosis
Muscle tissue is formed by the __________.
mesoderm
Prolactin causes __________.
milk production by the breast tissue
Which of the following events does NOT occur during the first 8 weeks of development?
myelination of the spinal cord
All of the following structures are derived from mesoderm EXCEPT __________.
nails
The first major event in organogenesis is __________.
neurulation
The first major event of organogenesis is __________.
neurulation
Sperm are known to bear __________ that respond to chemical stimuli that help them locate the oocyte.
olfactory receptors
Milk ejection (the letdown reflex) is stimulated by which of the following hormones associated with pregnancy?
oxytocin
Which maternally derived hormone induces and controls labor via a positive feedback mechanism?
oxytocin
Implantation of the blastocyst is the result of all of the following EXCEPT ______________.
phagocytosis by the trophoblast cells
Together, what do the decidua basalis and the chorionic villi form?
placenta
At which stage of labor is the "afterbirth" expelled?
placental
During early gastrulation, what structure(s) appear(s) on the dorsal aspect of the embryonic disc and establish(e)s the longitudinal axis of the embryo?
primitive streak
Which of the following serve(s) as the direct trigger to begin the more vigorous, rhythmic contractions of true labor?
prostaglandins
Which hormone produced by the placenta causes the mother's pubic symphysis to loosen and widen?
relaxin
Cells of the ________ gather around the notochord and neural tube and produce the vertebra and rib at their associated level.
sclerotome
Meconium is __________.
sloughed-off epithelial cells, bile, and other substances
Which of the following is the multicellular cytoplasmic mass formed from the outer layer of the trophoblast as it implants into the endometrium?
syncytiotrophoblast
Thalidomide was once used to treat intense nausea and morning sickness in pregnant women. Unfortunately, if administered at certain points during gestation it resulted in limb malformation. This drug is an example of a(n) ________.
teratogen
The neonatal period refers to _________.
the first month after birth
Which embryonic structure produces human chorionic gonadotropin (hCG)?
the syncytiotrophoblast
It is impossible for sperm to be functional (able to fertilize the egg) until after ___________.
they undergo capacitation
The only 100% effective method of birth control is __________.
total abstinence
Which of the following is NOT a function of the placenta?
urine formation
Which method of contraception is MOST reliable?
vasectomy
Derivatives of the mesoderm include ________.
vertebrae and ribs
Which of the following incorrectly matches an embryonic structure with its function?
yolk sac: provides nutrients to developing embryo
What destroys the zona pellucida sperm-binding receptors?
zonal inhibiting proteins
The correct sequence of preembryonic structures is _____________.
zygote, morula, blastocyst
