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Flashcards in Exam 1 Deck (45)
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1

What is the most common condition associated with spontaneously aborted embryos?
a. maternal imprinting
b. paternal imprinting
c. ectopic pregnancy
d. chromosomal abnormalities
e. lack of X-chromosomal inactivation

d. chromosomal abnormalities

2

What tissue from the implanting embryo directly interfaces with the endometrial connective tissue?
a. corona radiata
b. inner cell mass
c. extraembryonic membrane
d. epiblast
e. syncytiotrophoblast

e. syncytiotrophoblast

3

Identical twinning is made possible by what process or property of the early embryo?
a. regulation
b. aneuploidy
c. paternal imprinting
d. maternal imprinting
e. X-chromosomal inactivation

a. regulation

4

The zona pellucida:
a. aids in penetration of the endometrial epithelium
b. serves as a source of nutrients for the embryo
c. prevents premature implantation of the cleaving embryo
d. all of the above
e. none of the above

c. prevents premature implantation of the cleaving embryo

5

Of the barriers to sperm survival and transport within the female reproductive tract, low pH is most important in the:
a. upper uterine tube
b. lower uterine tube
c. uterine cavity
d. cervix
e. vagina

e. vagina

6

The principal energy source for ejaculated spermatozoa is:
a. prostatic acid phosphatase
b. internal glucose
c. prostatic citric acid
d. fructose in seminal vesicle fluid
e. glycogen released from the vaginal epithelium

d. fructose in seminal vesicle fluid

7

During spermatogenesis, histone is replaced by which of the following, to allow better packing of the condensed chromatin in the head of the spermatozoon?
a. inhibin
b. prostaglandin E
c. testosterone
d. protamine
e. androgen-binding protein

d. protamine

8

Which cell type is located outside the blood-testis barrier?
a. spermatozoon
b. secondary spermatocyte
c. spermatid
d. primary spermatocyte
e. spermatogonium

e. spermatogonium

9

Which of the following cells normally participates in mitotic divisions?
a. primary oocyte
b. oogonium
c. primary spermatocyte
d. spermatid
e. secondary spermatocyte

b. oogonium

10

In a routine chest x-ray examination, the radiologist sees what appear to be teeth in a mediastinal mass. What is the likely diagnosis, and what is a probable embryological explanation for its appearance?

A mediastinal teratoma, which is likely to have arisen from an aberrant primordial germ cell that became lodged in the CT near the heart.

11

When does meiosis begin in the female and in the male?

Females: meiosis begins during embryonic life
Males: meiosis begins at puberty

12

At what stages of oogenesis is meiosis arrested in the female?

At prophase (diplotene stage) of meiosis I and at metaphase of the meiosis II

13

What is the difference between spermatogenesis and spermiogenesis?

Spermatogenesis: entire process of sperm formation from a spermatogonium; includes the two meiotic divisions and the period of spermiogenesis.
Spermiogenesis, or sperm metamorphosis, is the process of transformation of a post meiotic spermatid, which looks like an ordinary cell, to a highly specialized spermatozoon.

14

The actions of what hormones are responsible for the changes in the endometrium during the menstrual cycle?

Estrogen, secreted by the ovary, support the preovulatory proliferative phase. From the time of ovulation, progesterone is secreted in large amounts by the corpus luteum and is responsible for the secretory phase, which prepares the endometrium for implantation of an embryo.

15

Sertoli cells in the testis are stimulated by what two major reproductive hormones?

Follicle-stimulating hormone (FSH) produced by the anterior lobe of the pituitary gland and testosterone produced by the Leydig cells of the testis.

16

What is the principal hormonal stimulus for ovulation?

The sharp surge of luteinizing hormone (LH) produced by the anterior lobe of the pituitary gland

17

What is capacitation?

Capacitation is a poorly understood interaction between a spermatozoon and female reproductive tissues that increases the ability of the sperm to fertilize an egg. In some mammals, capacitation is obligatory, but in humans the importance of capacitation is less well established.

18

Where does fertilization occur?

Fertilization usually occurs in the upper third of the uterine tube (ampulla)

19

Name two functions of the ZP3 protein of the Zona Pellucida.

The ZP3 protein acts as a specific sperm receptor through its O-linked oligosaccharides; much of its polypeptide backbone must be exposed to stimulate the acrosomal reaction.

20

What is polyspermy, and how is it prevented after a spermatozoon enters the egg?

Polyspermy is the fertilization of an egg by more than one spermatozoon. It is prevented through the fast electrical block on the plasma membrane of the egg and by the later zone reaction, by which products released from the cortical granules act to inactivate the sperm receptors in the zona pellucida.

21

A woman gives birth to septuplets. What is the likely reason for multiple births?

She had probably taken clomiphene for the stimulation of ovulation. Natural septuplets are almost never seen.

22

When multiple oocytes obtained by laparoscopy are fertilized in vitro, why are up to three embryos implanted into the woman's uterus, and why are the other embryos commonly frozen?

The introduction of more than one embryo into the tube of the woman is commonly done because the chance that any single implanted embryo will survive to the time of birth is quite small. The reasons for this are poorly understood. Extra embryos are frozen because if a pregnancy does not result from the first implantation, the frozen embryos can be implanted without the inconvenience and expense of obtaining new eggs from the mother and fertilizing them in vitro.

23

Why do some reproductive technology centers insert spermatozoa under the zone pellucid or even directly into the oocyte?

In cases of incompatibility between the sperm and egg, poor sperm motility, or deficient sperm receptors in the zone, introducing the sperm directly into or near the egg can bypass a weak point in the reproductive sequence of events.

24

What is the importance of the inner cell mass of the cleaving embryo?

The embryonic body proper arises from the inner cell mass

25

Parental imprinting is a phenomenon showing that certain homologous maternal and paternal chromosomes have different influences on the development of the embryo. Excess paternal influences result in the abnormal development of what type of tissue at the expense of development of the embryo itself?

Trophoblastic tissues

26

What is the function of integrins in implantation?

Interns allow the trophoblast of the embryo to adhere to the uterine epithelium

27

What is the cellular origin of the syncytiotrophoblast of the implanting embryo?

Cells derived form the cytotrophoblast fuse to form the syncytiotrophoblast (book says this but Anderson says from the trophoblast)

28

A woman who is 2 to 3 months pregnant suddenly develops severe lower abdominal pain. In the differential diagnosis, the physician must include the possibility of what condition?

In addition to the standard causes of lower abdominal pain, such as appendicitis, the physician should consider ectopic pregnancy (tubal variety) as a result of stretching and possible rupture of the uterine tube containing the implanted embryo.

29

What is a homeobox?

A homeobox is a highly conserved region consisting of 180 nucleotides that is found in many morphogenetically active genes. Homeobox gene products act as transcription factors.

30

Which of the following is a transcription factor?
a. FGF
b. Pax
c. TGF
d. Notch
e. Wnt

b. Pax