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Chapter 28 Pregnancy and Human Development

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The fertilized egg is known as the __________.
zygote
Sperm freshly deposited in the female vagina are incapable of fertilizing an egg. What must happen first?
capacitation
Which of the following is the primary germ layer that forms the basis for the digestive, respiratory, and urogenital systems, and for associated glands?
endoderm
What structure(s) ultimately form(s) the placenta?
decidua basalis and chorionic villi
A dangerous complication of pregnancy called __________ results in an insufficient placental blood supply, which can starve a fetus of oxygen. The pregnant woman becomes edematous and hypertensive, and proteinuria occurs.
preeclampsia
Which of the following INCORRECTLY matches an embryonic structure with its function?
yolk sac/provides nutrients to developing embryo
Which of the following structures is derived from the ectoderm?
brain and spinal cord
T/F: While human chorionic gonadotropin levels spike and sharply decline to reach a low value by four months, estrogen and progesterone levels steadily increase over the course of the pregnancy.
True
Which body system of a pregnant woman shows the most dramatic physiological changes during pregnancy?
cardiovascular system
In which stage of labor does crowning occur?
expulsion
What does the foramen ovale become at birth?
fossa ovalis
pregnant woman with preeclampsia becomes edematous and hypertensive. An effective way to treat these symptoms might be ______.
to use drugs that cause systemic vasodilatation
During a cesarean section, an incision is made through all EXCEPT which of the following?
...decidua basalis
T/F: A zygote is usually formed within the uterus.
False
T/F: Freshly deposited sperm are not capable of penetrating an oocyte.
True
T/F: Fertilization occurs while the egg is still in the ovarian follicle.
False
T/F: The period from fertilization through week eight is called the embryonic period
True
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
Select the correct statement about fertilization
Millions of sperm cells are destroyed by the vagina's acidic environment
How long is the egg viable and capable of being fertilized after it is ovulated?
12-24 hours
Proteases and acrosin are enzymes. How do they function in reproduction?
They act to break down the protective barriers around the egg, allowing the sperm to penetrate.
It is impossible for sperm to be functional (able to fertilize the egg) until after ________.
they undergo capacitation
What destroys the sperm receptors on the surface of the oocyte?
zonal inhibiting proteins
Once sperm are deposited into the vagina, sperm motility must be enhanced and they must be prepared to release hydrolytic enzymes from their acrosomes. What is this process called?
capacitation
What is the event that results when the maternal and paternal chromosomes combine?
fertilization
T/F: The "fluid-filled, hollow ball of cells" stage of development is the blastocyst.
True
T/F: A pregnancy test involves antibodies that detect GH levels in a woman's blood or urine.
False
T/F: By 72 hours after fertilization, the egg has divided into more than 160 cells and is called the morula.
False
T/F: Conceptus is a term used to describe the developing human offspring.
True
Which of the following is the correct sequence of development from zygote to embryo?
cleavage, morula, blastocyst, gastrula
The decidua basalis is ________.
located between the developing embryo and the myometrium
Cleavage as part of embryonic development is distinctive because it involves ________.
cell division by mitosis with little or no growth between successive divisions
Which hormone is not produced by the placenta?
inhibin
The trophoblast is mostly responsible for forming the ________.
placental tissue
Which hormone maintains the viability of the corpus luteum?
human chorionic gonadotropin
Which of the following events does not occur during the first 8 weeks of development?
myelination of the spinal cord
The correct sequence of preembryonic structures is ________.
zygote, morula, blastocyst
The placenta, a vitally important metabolic organ, is made up of a contribution from mother and fetus. Which portion is from the fetus?
chorion
Estrogen and progesterone maintain the integrity of the uterine lining and prepare the mammary glands to secrete milk. Which of the following structures makes this possible during the first three months of pregnancy?
corpus luteum
Together, what do the decidua basalis and the chorionic villi form?
placenta
How much time passes after fertilization until implantation occurs?
7 days
T/F: The embryo is directly enclosed in and protected by the amnion.
True
T/F: In fetal circulation, one way in which blood bypasses the nonaerated lungs is by way of the foramen ovale.
True
At what period of fetal development are all body systems present in at least rudimentary form?
8 weeks post fertilization
Derivatives of the endoderm include ________.
epithelium of the respiratory tract
Derivatives of the mesoderm include ________.
endothelium of blood and lymph vessels
Neural tissue is formed by the ________.
ectoderm
Muscle tissue is formed by the ________.
mesoderm
The dorsal surface cells of the inner cell mass form ________.
the primitive streak
T/F: The first major event in organogenesis is neurulation
True
Which of the following is derived from the somites of the mesoderm?
vertebrae and ribs
Which extra-embryonic membrane protects the developing embryo against physical trauma and helps maintain a constant homeostatic temperature?
amnion
T/F: The body systems of the developing embryo are present in at least rudimentary form at eight weeks.
True
Which fetal vascular shunt directly connects the right atrium to the left atrium so as to bypass the nonfunctional lungs?
foramen ovale
T/F: A pregnant woman urinates more often than usual because the uterus compresses the bladder, and she must also dispose of fetal metabolic wastes.
True
Relaxin is a hormone produced by the placenta and ovaries. The function of this hormone is to ________.
relax the pubic symphysis
T/F: The sole responsibility of the placenta is to supply the fetus with oxygen and nutrients
False
T/F: The placenta and its attached fetal membranes are collectively called the afterbirth
True
T/F: An episiotomy is an incision made to widen the vaginal orifice, aiding fetal expulsion.
True
During which stage of labor is the fetus delivered?
expulsion stage
At which stage of labor is the "afterbirth" expelled?
placental
A premature separation of the placenta from the uterine wall is called ________.
abrupto placenta
Which of the following is the longest stage of labor, lasting 6-12 hours or more?
dilation stage
The softening and thinning of the cervix during the dilation stage is known as ___________.
effacement
What is released from fetal lungs in the weeks before delivery to soften the cervix in preparation for labor?
surfactant protein A (SP-A)
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.
Hormones concerned with events of lactation include ________.
oxytocin
Milk ejection or letdown reflex is stimulated by which of the following hormones associated with pregnancy?
oxytocin
T/F: The birth control pill is the most common and most effective birth control method.
True
T/F: The embryonic stage lasts until the end of the eighth week.
True