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embryology > Chapter 3 Part 1 > Flashcards

Chapter 3 Part 1 Flashcards

1
Q

Controls the monthly sexual cycles

A

Hypothalamus

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2
Q

produced by the hypothalamus, acts on cells of the anterior lobe (adenohypophysis) of the pituitary gland, which in turn secrete gonadotropins

A

Gonadotropin-releasing hormone (GnRH)

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2
Q

Hormones that stimulate and
control cyclic changes in the ovary

A

follicle-stimulating hormone (FSH)
luteinizing hormone (LH),

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2
Q

Consequently, most follicles
degenerate without ever reaching full maturity.

A

TRUE

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2
Q

proliferation of follicular cells surrounding the oocyte is mediated by

A

Growth differentiation factor 9

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2
Q

The hormone is not necessary to promote development of primordial follicles to the primary follicle stage, but without it, these
primary follicles die and become atretic

A

follicle-stimulating hormone (FSH)

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2
Q

Theca interna cells produce _______

A

Androstenedione
Testosterone

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2
Q

What converts Androstenedione
and Testosterone to estrone and 17 B-estradiol

A

Granulosa cells

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2
Q

When a follicle becomes atretic, the oocyte and surrounding follicular cells degenerate and are replaced by connective tissue, forming a

A

corpus atreticum

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2
Q

Theca interna and granulosa cells produce ________

A

Estrogens

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2
Q

The oocyte is arrested in metaphase approximately how many hours before ovulation?

A

3 hours

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2
Q

At midcycle, there is an ________ that:
- Elevates concentrations of maturation promoting factor, causing oocytes to complete
meiosis I and initiate meiosis II
- Stimulates production of progesterone by follicular stromal cells (luteinization)
- Causes follicular rupture and ovulation

A

LH surge

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2
Q

High concentration of LH increases what activity that results in the digestion of collagen fibers surrounding the follicle?

A

Collagenase activity

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3
Q

What other level also increase in response to the LH surge and cause local ,muscular contractions in the ovarian wall

A

Prostaglandin Levels

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3
Q

Some of the cumulus oophorus
cells then rearrange themselves around the zona pellucida to form what?

A

corona radiata

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3
Q

German for
“middle pain”

A

mittelschmerz

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3
Q

Under the influence of LH, cells develop a yellowish pigment and change into ________ which forms the corpus luteum

A

Lutein cells

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4
Q

Progesterone, together with some
estrogen, causes the uterine mucosa to enter the ______________ in preparation for implantation of the embryo.

A

progestational or secretory stage

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5
Q

In humans, approximately how many days does it take for the fertilized oocyte to reach the uterine lumen?

A

3 to 4 days

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6
Q

If fertilization does not occur, the corpus luteum reaches maximum development approximately how many days after ovulation?

A

9 days

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7
Q

Subsequently the corpus luteum shrinks due to luteolysis and forms a mass of fibrotic scar tissue called _________

A

Corpus albicans

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8
Q

What prevents the degeneration of corpus luteum if the oocyte is fertilized?

it is also a hormone secreted
by the syncytiotrophoblast of the developing embryo

A

Human chorionic gonadotropin

9
Q

By the end of the third month, what is the size of the structure?

A

one-third to one-half of the total size of the ovary

10
Q

Yellowish luteal cells continue to secrete progesterone until
the end of the ________ month

A

fourth

11
Q

Removal of the corpus luteum of pregnancy before the fourth month usually leads to _______

A

abortion

12
Q

The process by which male and
female gametes fuse

A

Fertilization

13
Q

Where does fertilization occurs?

A

ampullary region of the uterine tube

14
Q

Spermatozoa may remain viable in the female reproductive tract for _________

A

several days

15
Q

The trip from cervix to oviduct can
occur as _____________

A

rapidly as 30 minutes or as slow as 6 days

16
Q

Spermatozoa must acquire something before it will be able to fertilize oocyte

A

Capacitation
Acrosome reaction

17
Q

Is a period of conditioning in the
female reproductive tract that in the human lasts approximately 7 hours

A

Capacitation

18
Q

Only __________ can pass through the corona cells and undergo the acrosome reaction

A

capacitated sperm

19
Q

occurs after binding to the zona pellucida and is induced by zona proteins

A

acrosome reaction

20
Q

phases of fertilization

A

Phase 1, penetration of the corona radiata
Phase 2, penetration of the zona pellucida
Phase 3, fusion of the oocyte and sperm cell membranes

21
Q

What phase is when Of the 200 to 300 million spermatozoa normally
deposited in the female genital tract, only 300 to 500 reach the site of fertilization. Only one of these fertilizes the egg

A

Phase 1: Penetration of the Corona
Radiata

22
Q
A

Phase 2: Penetration of the Zona
Pellucida

23
Q

is a glycoprotein shell surrounding the egg that facilitates and maintains sperm binding and induces the acrosome reaction

A

Zona

24
Q

Ligand mediating the binding and the acrosome reaction

A

ZP3

25
Q

The initial adhesion of sperm to the oocyte is mediated in part by the interaction of integrins on the
oocyte and their ligands, disintegrins, on sperm.

A

Phase 3: Fusion of the Oocyte and
Sperm Cell Membranes

26
Q

As a result of the release of cortical oocyte granules, which contain lysosomal enzymes the oocyte membrane becomes impenetrable to other spermatozoa

A

Cortical and zona reactions

27
Q

penetration of more than one spermatozoon into the oocyte

A

polyspermy

28
Q

The oocyte finishes its second meiotic
division immediately after entry of the spermatozoon

A

Resumption of the second meiotic division.

29
Q

One of the daughter cells, which
receives hardly any cytoplasm, is known as
the

A

second polar body

30
Q

the other daughter
cell is the

A

definitive oocyte

31
Q

Its chromosomes
(22 plus X) arrange themselves in a vesicular
nucleus known as the

A

female pronucleus

32
Q

The activating
factor is probably carried by the spermatozoon.
Activation encompasses the initial
cellular and molecular events associated with
early embryogenesis.

A

Metabolic activation of the egg

33
Q

The spermatozoon, meanwhile, moves forward
until it lies close to the female pronucleus.
Its nucleus becomes swollen and forms the

A

male
pronucleus

34
Q

Main results of fertilization

A

Restoration of the diploid number of chromosomes
Determination of the sex of the new individual
Initiation of cleavage

35
Q

Without fertilization, how many hours does it take for the oocyte to degenerate after ovulation?

A

24 hours

36
Q

Once the zygote has reached the two-cell stage, it undergoes a series of mitotic divisions, increasing the numbers of cells. These cells, which become smaller with each cleavage division, are known as

A

blastomeres

37
Q

segregates inner
cells, which communicate extensively by gap
junctions, from outer cells

A

compaction

38
Q

Approximately 3 days after fertilization, cells of the compacted
embryo divide again to form a

A

16-cell morula

39
Q

line inner cell mass
gives rise to tissues of the

A

embryo proper

40
Q

the outer cell mass forms the _______, which
later contributes to the placenta

A

trophoblast

embryology (6 decks)

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