Chapter 1: Getting Ready for Pregnancy

Question 1

Gametogenesis Phase 1:

Answer 1

primordial germ cells originate in endodermal layer of yolk sac (develop outside embryonic tissues)

recognizable 24 days after gestation-large and high [alkaline phosphatase]

migrate through dorsal mesentry and enter primitive gonads

teratomas: misdirected germ cells, pluripotent; occur in oral, sacral areas and behind the heart

Question 2

Phase 2: mitotic division increases cellular numbers FEMALES

Answer 2

in females, oogonia: mitotically active female germ cells; egg cell that is not yet in meiosis

intense meiotic activity from 2-5 months of pregnancy with 7 million produced

most undergo atresia

Question 3

atresia of egg cells

Answer 3

natural degradation due to lack of space, nutrients, chromosomal stability, etc.

Question 4

phase 2: MALES

Answer 4

spermatogonia divide up and take up space in gonads; division not as intense

seminiferous tubules become lined with germinative layer

at puberty, subpopulations undergo periodic waves of mitosis

Question 5

type A spermatogonia

Answer 5

continue to undergo mitosis (stem cells)

Question 6

type B spermatogonia

Answer 6

undergo meiosis; arise from type A

connected by cytoplasmic bridges surrounded by Seritoli cells

Question 7

phase 3: reduction of chromosomal number by meiosis

Answer 7

2n 2c before meiosis——–double chromosomal number————2n 4c ———1st meiotic division ———CENTROMERE DODES NOT SPLIT——– 2 (1n 2c)—–2nd meiotic division ——– 4 (1n 1c)

1n 1c = truly haploid cells

Question 8

reductional division

Answer 8

prophase 1: prolonged, homologous recombination within chromosomes

metaphase I: tetrads line up at metaphase plate

anaphase I: no centromeric division; daughter cells genetically unequal (1n 2c chromosomes contain 2 chromatids connected by a centromere)

telophase I: incomplete cellular division in spermatid production

Question 9

equatorial division

Answer 9

prophase II, metaphase II

anaphase II: centromeric division; daughter cells genetically unequal (1n, 1c)

telophase II: results in production of 4 truly haploid gametes in sperm

Question 10

crossing over

Answer 10

not purely random; occurs a certain hot spots

hypermethylation occurs where DNA strand will break and later be repaired after crossing over

Question 11

cohesin

Answer 11

helps hold sister chromatids together during division

Question 12

condensin

Answer 12

important for compaction of chromosomes

Question 13

women 1st meiotic division

Answer 13

begun in late fetal period; completed immediately prior to ovulation

2dary oocyte and polar body: oocyte begins second meiotic division but encounter meiotic block that can only be surpassed with fertilization by spermatozoon

Question 14

meiosis in men

Answer 14

does not begin till after puberty and not all spermatogonia enter meiosis at the same time

Question 15

blocks to maturation in women

Answer 15

cAMP (from oocyte and follicle) gets converted into 5’ AMP by PDE3A, which is inhibited by cGMP produced by follicular cells

cAMP also inhibits MPF (maturation promoting factor)

Question 16

gap junctions

Answer 16

form between primary oocyte and follicular cells

allows for transport of materials

Question 17

structure of egg and follicle

Answer 17

nucleus–oocyte–zona pellucida–granulosa cells—membrane granulosa—theca interna — theca externa

Question 18

oocyte

Answer 18

relies on diffusion and gap junctions to survive; microvilli also play a role

Question 19

zona pellucida

Answer 19

prominent, translucent, noncellular membrane (glycoproteins, glycosamines, sperm receptors )

Question 20

membrane granulosa

Answer 20

basement membrane of granulosa cells (capillary barrier)

Question 21

theca interna

Answer 21

highly vascularized tissue;

have LH receptors

produce androgens in response to LH surge (converted by granulosa cells into 17beta-estradiol which stimulates LH receptors on granulosa cells)

secrete angiogenesis factor to support follicular growth

Question 22

antrum

Answer 22

develops in the secondary follicle

cavity filled with liquor folliculi

Question 23

liquor folliculi

Answer 23

contains serum proteins in low concentrations, enzymes, hormones, proteoglycans with low negative charge to attract water

Question 24

cumulus cells

Answer 24

cells immediately surrounding the oocyte

don’t develop hormone receptors but do help release ovum at time of ovulation

Question 25

mural granulosa cells

Answer 25

cells between antrum and membrane granulosa

develop normally with hormone receptors

Question 26

activin

Answer 26

works with FSH to signal granulosa cell proliferation

Question 27

theca externa cells

Answer 27

connective tissue-like capsule

Question 28

granulosa cells

Answer 28

respond to FSH by producing estrogens; proliferation under activing and FSH

produce aromatase (converts androgens into 17beta-estradiol)

Question 29

LH surge

Answer 29

signals the resumption of meiosis

LH–cumulus cell—(shut down gap junctions)–reduces transfer of cAMP and cGMP from cumulus into ovum–activation of PDE3A—(breakdown of intraoocyte cAMP into 5’AMP)—-activation of MPF–resumption of meiosis

Question 30

inhibin

Answer 30

allows for the formation of one dominant follicle

7 days before ovulation one of the follicles becomes FSH independent and secretes inhibin which shuts of secretion of FSH from the pituitary thus killing all the other follicles still dependent on FSH

Question 31

graafian follicle

Answer 31

at or just prior to ovulation, 1st meiotic division is complete

2dary oocyte and polar body within cumulus oophorus

oocyte factors cause cumulus cells to respond to gonadotropic hormones by hyaluronic acid production

Question 32

female hormone wire diagram

Answer 32

[see paper flashcard]

Question 33

retinoic acid

Answer 33

stimulates entry into meiosis in males

Question 34

Seritoli cells

Answer 34

“nurse cells” ; surround the sperm and protect them from immune system

help sculpt sperm into mature cells

Question 35

beginning of spermatogenesis

Answer 35

spermatogonia sequestered at the bottom of seminiferous epithelium by Seritoli cells

once type B progeny (primary spermatocytes) finish leptotene stage of first meiotic division, they pass through Sertoli cells into seminiferous tubules

Seritoli cells form blood-testis barrier ; when spermatogonia begin meiosis they are immunologically different from the rest of the body

produce in advance molecules that are needed at later periods when change occurs rapidly, like protamines

Question 36

spermiogenesis

Answer 36

spermatids to mature spermatozoa

1. reduce size of nucleus and condense DNA by replacing histones with protamines
2. cytoplasm moves away from nucleus
3. condensation of Golgi to form the acrosome
4. flagellum grows out of centriolar region
5. mitochondria spiral around proximal part of flagellum
6. plasma membrane at head of sperm arranged into separate molecular domains
7. remainder of cytoplasm (residual body) moves away from nucleus and is shed (phagocytozed by Sertoli cells)

at this point the sperm are not yet motile

takes 64 days

Question 37

biochemical maturation of sperm

Answer 37

glycoprotein coating and surface modification in epididymis

prevents fertilization; stops sperm from mating with the first cell they encounter

Question 38

capacitation

Answer 38

removal of glycoprotein coat to allow fertilization

Question 39

male hormone wiring diagram

Answer 39

[see paper flashcard]

Question 40

ICSH

Answer 40

interstitial cell stimulating hormone in males

chemically identical to LH in females

Question 41

LCSF

Answer 41

Leydig cell stimulating factor; increases secretion of ICSH

Question 42

ABP

Answer 42

androgen binding protein; together with testosterone promotes spermiogenesis

Question 43

histones vs. protamines

Answer 43

histones contain Lys(+) (-)DNA

Protamines contain Arg(+), Cys (capable of forming disulfide bridges)

Question 44

Rule of 60s

Answer 44

numerical evaluation of whether or not you’re sterile

need to…..

1. produce 60 million sperm/mL
2. 60% of 60 million must be motile
3. 60% of motile must be structurally normal

20 million viable sperm/mL to be fertile

Question 45

seminiferous tubules vs. epididymis

Answer 45

seminiferous: structural maturation
epididymis: biochemical maturation (glycoprotein coating and surface modification)

Question 46

uterine tube

Answer 46

three sections: ampulla, isthmus, intramural

fimbriae project out towards ovary from the open infidibulum of uterine tubue

Question 47

intramural segment

Answer 47

embedded within uterus wall, thin lumen and mucus that varies and regulates passage of sperm/bacteria into uterus

Question 48

isthmus

Answer 48

temporary storage of sperm;

participates in final stages of functional maturation of sperm cells

Question 49

endometrium

Answer 49

uterine mucosa

receives and maintains the embryo

Question 50

myometrium

Answer 50

smooth muscular wall used to push out the fetus

Question 51

functional layer of endometrium

Answer 51

shed at each period

Question 52

basal layer of endometrium

Answer 52

remains intact at each period

Question 53

general structure of uterus

Answer 53

1. columnar surface epithelium
2. uterine glands
3. specialized connective tissue stroma
4. spiral arteries that coil from basal layer towards the surface

Question 54

cervix

Answer 54

mucousal surface which isn’t typical endometrial epithelium;
varies throughout the cycle
rich in glycoprotein

Question 55

vagina

Answer 55

stratified squamous epithelium;

deposits of glycogen that are broken down to increase acidity

Question 56

hypothalamus

Answer 56

releases GnRH

Question 57

anterior pituitary

Answer 57

GnRH causes release of FSH and LH (gonadotropic hormones); also prolactin (inhibited by dopamine)

Question 58

posterior pituitary

Answer 58

oxytocin released

Question 59

ovaries and placental hormonal control

Answer 59

granulosa cells take theca interna cell produced androgens and convert them into 17beta-estradiol

after ovulation, progesterone produced by corpus luteum

placental produces its own progesterone and estrogen; human chorionic gonadotropin, human placental lactogen (acts on corpus luteum)

Question 60

target tissue hormonal control

Answer 60

changes in number of ciliated cells, smooth muscle activity in uterine tubes

changes in endometrial lining

cyclical changes in glandular breast tissues

estrogen primes target tissues for progesterone by inducing progesterone receptors

Question 61

Proliferative Phase (days 5-14)

Answer 61

estrogen dominated

uterine lining reepithiliazed

uterine glands elongate

endometrial stroma thickens

spiral arteries grow towards surface

cervix secrets E mucus to let sperm pass

high % of uterine tubes becomes ciliated and smooth muscle activity increases

fimbriae move closer towards end of stage

high levels of estradiol produced by follicle increase responsiveness of anterior pituitary to GnRH and increase in GnRH leads to LH surge (the signal for ovulation); granulosa cells now produce progesterone

Question 62

Secretory Phase (14-28)

Answer 62

after LH surge, increase in basal body temperature

estrogen and progesterone in blood, smooth muscle contraction to move ovulated egg towards uterus

progesterone primes endometrium for implantation

spiral arteries grow towards surface

decrease in mitotic activity of endometrial cells

cervical mucus becomes thick

vaginal epithelium now thinner

endometrium of uterine tubes undergoes regression

Question 63

no pregnancy effects

Answer 63

inhibin produced by granulosa cells

decrease in LH and FSH

regression of corpus luteum

Question 64

estrogen vs. progesterone

Answer 64

estrogen responsible for STRUCTURAL developments

FUNCTIONAL developments happen with progesterone