A&P II Chapter 28 Pregnancy

How long is the secondary oocyte viable and capable of being fertilized after it is ovulated?

12-24 hours

Which of the following is NOT a change in female anatomy or physiology during pregnancy?

A tightening of pelvic ligaments to help bear the extra weight of the growing fetus

A couple undergoes a workup for infertility, which shows that the man has a low sperm count. The couple asks why this is a problem because "it only takes one sperm to fertilize an egg." How could you explain their problem?

Although a single sperm fertilizes the egg, many others prepare the egg for its entry.

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

Humans do not have a yolk sac associated with embryonic development.

False

Premature infants often need to be placed on a ventilator because their undeveloped lungs produce excess surfactant.

False

True fertilization occurs when the sperm's membrane binds to the oocyte's sperm-binding receptors.

False

A friend confides that she desires to have children but is having trouble conceiving. Which of the following is true regarding implantation?

It is estimated that a minimum of two-thirds of all zygotes formed fail to implant by the end of the first week or spontaneously abort.

Select the correct statement about fertilization.

Millions of sperm cells are destroyed by the vagina's acidic environment.

What role does oxytocin play in promoting labor?

Oxytocin stimulates the uterus to contract.

Which of the following statements about the acrosomal reaction is correct?

The acrosomal enzymes released from many sperm digest holes through the zona pellucida.

Which of the choices below occurs if implantation is successful?

The corpus luteum is maintained until the placenta takes over its hormone-producing functions.

The cardiovascular system of a newborn must be adjusted after the infant takes its first breath. Which of the following is also true?

The ductus arteriosus constricts and is converted to the ligamentum arteriosum.

Select the correct statement about the special fetal blood vessels.

The umbilical vein becomes the ligamentum teres.

Which statement best describes the result of binding and fusion of the sperm's membrane to the oocyte plasma membrane?

They allow the contents of the sperm to enter the oocyte cytoplasm.

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 increased, and she must also dispose of fetal metabolic wastes.

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

Freshly deposited sperm are not immediately capable of penetrating an oocyte.

True

Implantation begins six to seven days after ovulation.

True

In fetal circulation, one way in which blood bypasses the nonfunctional lungs is by way of the foramen ovale.

True

Of the three germ layers, the mesoderm forms the most body parts.

True

The "fluid-filled, hollow ball of cells" stage of development is the blastocyst.

True

The embryo is directly enclosed in and protected by the amnion.

True

The embryonic period lasts until the end of the eighth week.

True

The period from fertilization through week eight is called the embryonic period.

True

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

The result of polyspermy in humans is ________.

a nonfunctional zygote

Human chorionic gonadotropin (hCG) is at its highest levels ________.

about 2 months after implantation during the 8th gestational week

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.

Which of the following implants in the mucosa of the endometrium?

blastocyst

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

Which body system of a pregnant woman undergoes the most dramatic physiological changes during pregnancy?

cardiovascular system

The placenta, a vitally important metabolic organ, is made up of a contribution from mother and fetus. Which portion is from the fetus?

chorion

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 term, by definition, includes all the other terms?

conceptus

What reaction prevents more than one sperm from binding to an oocyte during fertilization?

cortical reaction

Which of the following is the longest stage of labor, lasting 6-12 hours or more?

dilation stage

Which of the following is NOT a correct matching of a fetal structure with what it becomes at birth?

ductus arteriosus-ligamentum teres

Neural tissue is formed by the ________.

ectoderm

Derivatives of the endoderm include ________.

epithelial lining of the respiratory tract

The corpus luteum prevents loss of the implanted embryo through menstruation by secreting ________.

estrogens and progesterone

During which stage of labor is the fetus delivered?

expulsion stage

At what point is meiosis II completed for the female gamete?

fertilization

Which fetal vascular shunt directly connects the right atrium to the left atrium so as to bypass the nonfunctional lungs?

foramen ovale

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)

The presence of endoderm, ectoderm, and mesoderm is first seen in the ________ stage.

gastrula

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

Which hormone maintains the viability of the corpus luteum?

human chorionic gonadotropin

A urine test reveals a positive result for human chorionic gonadotropin (hCG). This indicates ________ was successful.

implantation

The most common assisted reproductive technology process used by couples having difficulty conceiving is _______.

in vitro fertilization

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

Which of the following events does NOT occur during the first 8 weeks of development?

myelination of the spinal cord

The first major event in organogenesis is ________.

neurulation

Which of the following is true in reference to what may pass through the placental barriers?

nutrients, respiratory gases, wastes, and alcohol

Milk ejection (the letdown reflex) is stimulated by which of the following hormones associated with pregnancy?

oxytocin

Which hormone is NOT produced by the placenta?

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

The trophoblast is mostly responsible for forming the ________.

placental tissue

Gastrulation begins when a groove with raised edges called the ________ appears on the dorsal surface of the embryonic disc.

primitive streak

Which of the following serve(s) as the direct trigger to begin the more vigorous, rhythmic contractions of true labor?

prostaglandins

The foramen ovale and the ductus arteriosus are both examples of __________.

pulmonary bypass shunts, which serve to bypass the lungs

Relaxin is a hormone produced by the placenta and ovaries. The function of this hormone is to ________.

relax the pubic symphysis

Sperm move to the uterine tube through uterine contractions and the energy of their own flagella. What other factor is involved in sperm movement?

reverse peristalsis of the uterus and uterine tubes

Cells of the ________ gather around the notochord and neural tube and produce the vertebra and rib at their associated level.

sclerotome

A lack of _____ can, without treatment, lead to _____ in premature infants.

surfactant; alveolar collapse

Which of the following is NOT assessed as part of the Apgar score?

temperature

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

The decidua basalis is ________.

the part of the endometrium that lies beneath the embryo

Which embryonic structure produces human chorionic gonadotropin (hCG)?

the syncytiotrophoblast

Shortly after implantation, ________.

the trophoblast forms two distinct layers

It is impossible for sperm to be functional (able to fertilize the egg) until after ________.

they undergo capacitation

Which of the following takes oxygenated blood to the liver from the placenta?

umbilical vein

Which method of contraception is most reliable?

vasectomy

Derivatives of the mesoderm include ________.

vertebrae and ribs

What destroys the zona pellucida sperm-binding receptors?

zonal inhibiting proteins

The correct sequence of preembryonic structures is ________.

zygote, morula, blastocyst