Chapter 28 Flashcards

1) Cells on the dorsal surface of the two-layered embryonic disc migrate to form a raised groove known as the ________.
A) blastocyst
B) amnion formation
C) germ cell formation
D) primitive streak

2) The result of polyspermy in humans is ________.
A) multiple births
B) a nonfunctional zygote
C) interruption of meiosis
D) mitotic insufficiency

3) It is impossible for sperm to be functional (able to fertilize the egg) until after ________.
A) the tail disappears
B) they become spermatids
C) they undergo capacitation
D) they have been stored in the uterus for several days

4) Milk ejection or letdown reflex is stimulated by which of the following hormones associated with pregnancy?
A) inhibin
B) oxytocin
C) prolactin
D) gonadotropin

5) 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?
A) the amnion
B) the chorion
C) corpus luteum
D) corona radiata

6) The placenta, a vitally important metabolic organ, is made up of a contribution from mother and fetus. Which portion is from the fetus?
A) chorion
B) umbilicus
C) yolk sac
D) amnion

7) Relaxin is a hormone produced by the placenta and ovaries. The function of this hormone is to ________.
A) block the pain of childbirth
B) ensure the implantation of the blastula
C) relax the pubic symphysis
D) prevent morning sickness

8) Proteases and acrosin are enzymes. How do they function in reproduction?
A) They neutralize the mucous secretions of the uterine mucosa.
B) They direct the sperm to the egg through chemical messengers.
C) They act to break down the protective barriers around the egg, allowing the sperm to penetrate.
D) Their function is unknown.

9) Which of the following is not a germ layer?
A) ectoderm
B) mesoderm
C) epiderm
D) endoderm

10) The formation of endodermal and ectodermal germ layers occurs at ________.
A) fertilization
B) cleavage
C) gastrulation
D) blastula formation

11) Which hormone maintains the viability of the corpus luteum?
A) estrogen
B) progesterone
C) human chorionic gonadotropin
D) human placental lactogen

12) Which of the following is a highly unlikely method of producing a child?
A) embryo transfer
B) ectopic implantation
C) in vitro fertilization
D) gamete intrafallopian transfer

13) Which of the following is not a correct matching of a fetal structure with what it becomes at birth?
A) foramen ovalefossa ovalis
B) ductus arteriosusligamentum teres
C) ductus venosusligamentum venosum
D) umbilical arteriesmedial umbilical ligament

14) Implantation involves ________.
A) placenta completion
B) formation of germ layers
C) fusion of egg and sperm
D) embedding of the blastocyst in the uterine wall

15) The umbilical arteries carry ________.
A) waste products to the placenta
B) oxygen and food to the fetus
C) oxygen and metabolic wastes to the placenta
D) oxygen and waste products to the fetus

16) The correct sequence of preembryonic structures is ________.
A) zygote, blastocyst, morula
B) zygote, morula, blastocyst
C) blastocyst, morula, zygote
D) morula, zygote, blastocyst

17) Which of the following is not assessed as part of the Apgar score?
A) heart rate
B) respiration
C) muscle tone
D) temperature

18) Hormones concerned with events of lactation include ________.
A) estrogen
B) oxytocin
C) progesterone
D) hCG

19) Initially, the implanted embryo obtains its nutrition by ________.
A) simple diffusion of nutrients from the uterine secretions
B) nutrient stores in the embryonic cells
C) the blood supply of the placenta
D) digestion of endometrial cells

20) Onset of labor may be a result of all of the following factors except ________.
A) secretion of oxytocin
B) high estrogen levels
C) aspirin and similar drugs
D) contraction-related increased emotional and physical stress

21) Select the correct statement about fertilization.
A) Both spermatozoa and the ovulated secondary oocyte remain viable for about 72 hours in the female reproductive tract.
B) Millions of sperm cells are destroyed by the vagina's acidic environment.
C) If estrogen is present, the pathway through the cervical opening is blocked from sperm entry.
D) Once inside the uterus, most sperm cells are protected and remain viable

22) Shortly after implantation ________.
A) maternal blood sinuses bathe the inner cell mass
B) myometrical cells cover and seal off the blastocyst
C) the trophoblast forms two distinct layers
D) the embryo gastrulates (within 3 days)

23) The dorsal surface cells of the inner cell mass form ________.
A) a structure called the embryonic disc
B) one of the fetal membranes
C) the primitive streak
D) the notochord

24) Muscle tissue is formed by the ________.
A) mesoderm
B) ectoderm
C) endoderm
D) epiderm

25) Neural tissue is formed by the ________.
A) epiderm
B) endoderm
C) mesoderm
D) ectoderm

26) The trophoblast is mostly responsible for forming the ________.
A) allantois
B) archenteron
C) placental tissue
D) lining of the endometrium

27) The cardiovascular system of a newborn must be adjusted after the infant takes its first breath. Which of the following is also true?
A) The foramen ovale between the atria of the fetal heart closes at the moment of birth.
B) The ductus venosus is disconnected at the severing of the umbilical cord and all visceral blood goes into the vena cava.
C) The urinary system is activated at birth.
D) The ductus arteriosus constricts and is converted to the ligamentum arteriosum.

28) Sperm move to the uterine tube through uterine contractions and the energy of their own flagella. What other factor is involved in sperm movement?
A) hormonal attraction to the ova
B) reverse peristalsis of the uterus and uterine tubes
C) the cilia on the apex of the cells lining the endometrium
D) the increased temperature in the vagina, which stimulates sperm motility

29) At which stage of labor is the "afterbirth" expelled?
A) dystocia
B) expulsion
C) placental
D) full dilation

30) Which hormone is not produced by the placenta?
A) human placental lactogen
B) human chorionic thyrotropin
C) relaxin
D) inhibin

31) During which stage of labor is the fetus delivered?
A) dilation stage
B) expulsion stage
C) placental stage
D) gastrula stage

32) Implantation of the blastocyst is the result of all of the following except ________.
A) phagocytosis by the trophoblast cells
B) proteolytic enzymes produced by the trophoblast cells
C) settling of the blastocyst onto the prepared uterine lining
D) adherence of the trophoblast cells to the endometrium

33) Cleavage as part of embryonic development is distinctive because it involves ________.
A) cell division by mitosis with little or no growth between successive divisions
B) the fusion of gametes
C) splitting the cell into two separate cells
D) meiosis

34) Which of the following is true in reference to what may pass through the placental barriers?
A) nutrients and respiratory gases only
B) hormones, blood cells, and nutrients
C) nutrients, respiratory gases, wastes, and alcohol
D) respiratory gases, hormones, nutrients, and blood cells

35) Which of the following is not usually considered a teratogen?
A) aspirin
B) wine
C) thalidomide
D) German measles

36) Derivatives of the ectoderm include ________.
A) serosae of the ventral body cavity
B) epithelium of the reproductive tract
C) epithelium of the pineal and pituitary glands
D) connective tissues

37) Derivatives of the mesoderm include ________.
A) all nervous tissue
B) endothelium of blood and lymph vessels
C) glandular derivatives of the digestive tract
D) epithelium of the digestive tract

38) Derivatives of the endoderm include ________.
A) epithelium of the respiratory tract
B) synovial membranes of the joints
C) blood, bone marrow, and lymphoid tissue
D) organs of the urogenital system

39) Developmental events during weeks 9-12 include ________.
A) sex readily detected from the genitals
B) the cardiovascular system becoming fully functional
C) head larger than body
D) fetal position assumed

40) Which of the choices below occurs if fertilization of the ovum occurs and implantation takes place?
A) The corpus luteum is maintained until the placenta takes over its hormone-producing functions.
B) The corpus luteum degenerates and becomes the corpus albicans.
C) The ovarian cycle begins.
D) Increased levels of FSH will be produced.

41) Select the correct statement about the special fetal blood vessels.
A) The distal parts of the umbilical arteries form the superior vesical arteries.
B) The fossa ovalis becomes the foramen ovale.
C) The umbilical vein becomes the ligamentum teres.
D) The hepatic portal vein forms from the umbilical artery.

42) Which of the following statements about the events of fertilization is not true?
A) The two pronuclei divide.
B) The head of the sperm forms the male pronucleus.
C) The secondary oocyte completes the second meiotic division.
D) Proteases and acrosin proteinases of the sperm disperse the cells of the corona radiata of the oocyte

43) The decidua basalis is ________.
A) destined to remain in the uterus after the birth of the infant
B) located between the developing embryo and the myometrium
C) not a maternal contribution to the placenta
D) the tissue that surrounds the uterine cavity face of the implanted embryo

True or False

Conceptus is a term used to describe the developing human offspring.

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

Fertilization occurs while the egg is still in the ovarian follicle.

Freshly deposited sperm are not capable of penetrating an oocyte.

By 72 hours after fertilization, the egg has divided into more than 160 cells and is called the morula.

Implantation begins six to seven days after ovulation.

A pregnancy test involves antibodies that detect GH levels in a woman's blood or urine.

The body systems of the developing embryo are present in at least rudimentary form at eight weeks.

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

A pregnant woman urinates more often than usual because the uterus compresses the bladder, and she must also dispose of fetal metabolic wastes.

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

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

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

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

An episiotomy is an incision made to widen the vaginal orifice, aiding fetal expulsion.

The placenta and its attached fetal membranes are collectively called the afterbirth.

Human placental lactogen initiates labor.

Surfactant production in premature infants is rarely a factor in providing normal respiratory activity.

A blastocyst is a hollow ball of cells, while the morula is a solid ball of cells.

A zygote is usually formed within the uterus.