Lec 29 Sexual Differentiation Pt 2

Question 1

What are primordial germ cells? where do they come from?

Answer 1

• precursor cells to gametes
• migrate from origin in hindgut of embro to gonads
• multiply and become spermatogonia/oogonia

Question 2

When do ovum complete mitosis?

Answer 2

in fetus

Question 3

when do ovum complete meiosis I

Answer 3

at ovulation

Question 4

What hormone dominates first half of menstural cycle? second half?

Answer 4

• estrogen dominates first half

- progesterone dominates second half

Question 5

What is day 1 of menstrual cycle?

Answer 5

first day of menstruation

Question 6

What is negative feedback of estradiol in ovaries?

Answer 6

• inhibits hypo secretion of GnRH

- inhibits pituitary secretion of LH/FSH

Question 7

What 3 things involved in follicular growth

Answer 7

• multiplication of granulosa cells
• development of antrum [follicular fluid]
• growth of oocyte

Question 8

what cells in follicle respond to FSH? LH?

Answer 8

• granulosa cells respond to FSH

- theca cells respond to LH

Question 9

what two cells involved in estrogen production from ovary? path?

Answer 9

• theca cells respond to LH, make androgens
• androgens transported to granulosa cells
• granulosa cells respons to FSH, convert androgen –> estradiol

Question 10

What cells make inhibin? what is function?

Answer 10

• granulosa cells make inhibin

- inhibin decreases FSH

Question 11

During menstruation how do you end up with just 1 follicle?

Answer 11

• start out with 20-25 follicles in cycle
• the follicle with the most FSH receptors will win out
• others don’t have enough FSH and undergo atresia

Question 12

When does the follicle cohort for a given menstrual cycle get chosen?

Answer 12

100 days [2-3 months] before the cycle

Question 13

When is the follicular phase of the menstrual cycle?

Answer 13

0-14 days of menstrual cycle

Question 14

Is follicular or luteal phase of menstrual cycle variable?

Answer 14

follicular

Question 15

What are progesterone levels like in follicular phase?

Answer 15

low

Question 16

What causes ovulation

Answer 16

• super high estrogen above certain level for long enough causes negative feedback on LH to become positive feedback and you get

Question 17

What does LH surge do to follicle

Answer 17

• allows completion 1st meiotic division and start of 2nd division
• causes loosening of cumulus cells so egg can be released from follicle
• causes secretion

Question 18

What is role of prostaglandins in ovulation?

Answer 18

• secreted by follicle, break down wall of follicle to allow ovulation

Question 19

What causes transformation ruptured follicle to corpus luteum?

Answer 19

• thecal cells and blood vessels invade

- granulosa cells hypertrophy and terminally differentiate = luteinization

Question 20

what 2 things does CL make?

Answer 20

progesterone

estradiol

Question 21

What happens to cervical mucus in ovulation?

Answer 21

• increased quantity of cervical mucus

- becomes less viscous and more penetrable to sperm

Question 22

What happens to uterus in menstrual cycle [2 phases]?

Answer 22

proliferative phase: estrogen causes uterine lining to proliferate

secretory phase: glands in uterus become secretory, secrete substances to nurture pregnancy

Question 23

What is optimal time for implantation in uterus?

Answer 23

• day 21

Question 24

How does body temp change in luteal phase?

Answer 24

• increased basal body temp because progesterone effects hypothalamic thermoregulatory center

Question 25

How much blood normally loss in menstruation?

Answer 25

60 ccs

Question 26

5 ways to check for ovulation

Answer 26

- basal body temp - plasma estradiol - plasma progesterone - volume of cervical mucus - uterine endometrium

Question 27

What is the simplest way to detect ovulation?

Answer 27

progesterone

Question 28

What is function of FSH?

Answer 28

- stimulates follicle development - induces granulosa cells to produce estrogen from androgen [using aromatase] - induces formation LH receptors - selects pre-ovulatory follicle

Question 29

what is function of LH?

Answer 29

- produces androgens in theca cells - stimulates last stages of follicle development - induces ovulation and final follicle maturation - stimulates formation corpus luteum

Question 30

at what day does oocyte enter uterus?

Answer 30

day 5-6

Question 31

What happens in implantation?

Answer 31

- blastocyst hatches from zona pellucida | - invasion of trophoblasts

Question 32

What maintains corpus luteum in pregnancy?

Answer 32

hCG