Female reproductive physiology

Question 1

Describe the “job sharing” involved in the two cell hypothesis

Answer 1

Progesterone (grarnulosa) –>Theca cell–>Androstenedione–>Granulosa cell –> aromatase activity = Estrone –> 17-HSD = Estradiol

Question 2

LH stimulates tehca cells via cAMP to increase synthesis of what receptors? Why?

Answer 2

LDL

HDL

Help outsource cholesterol

Question 3

After puberty formation of secondary follicle from primary follicle is characterized by..?

Answer 3

The addition of the thecal layer of cells

Question 4

Once the baby is born up until the age of 50, these cells remain arrested in prophase of meiosis 1. Name these cells and the signaling molecule responsible for maintaining the arrested state of these cells:

Answer 4

Oogonium

cAMP

Question 5

Over the course of the menstrual cycle, specifically ovulation, the oogonia matures into a new cell and completes meiosis 1. At this time there is the formation/extrusion of the first polar body, as well as another cell. What is the DNA content vs the chromosome number of this new cell and what new phase is it arrested in?

Answer 5

Primary oocyte

DNA content = 2N

Chromosome = 1N

Arrested in metaphase 1 unless fertilization occurs

Question 6

Should fertilzation occur what process will be completed, what will be the new ploidy, and what is this cell known as?

Answer 6

2nd meitoic division

DNA content/Chromosome # = 1N

Secondary oocyte

Question 7

Define the term Atresia. What are the approximate values of female gametes over the course of their reproductive lifetime due to this phenomenon?

Answer 7

Programmed cell death of a cell line

7 million @5th month of gestation

<300,000 @ menarche (ovarian reserve)

<30,000 @ fertilzation (growth)

<500 @ post fertilzation (ovarian ovulation)

Question 8

What is the most variable part of the menstrual cycle?

Answer 8

Follicular phase

–>can be 9-23 days

Question 9

Production of what hormone is promoted during high frequency pulses of GnRH (1p/60-90 min)?

Answer 9

LH

Question 10

Production of what hormone is promoted during low frequency pulses of GnRH (1p/120min)?

Answer 10

FSH

Question 11

Within the ovary, the follicular and luteal phase is separated by what process?

Answer 11

Ovulation

Question 12

Early follicular phase

Answer 12

small rise in FSH recruits primary follicles which begin rapid, FSH-dependent granulosa cell growth, producing low levels of estrodiol and inhibin B

Question 13

In mid follicular phase

Answer 13

local estradiol increases its own receptors and FSH receptors on granulosa cells of dominant follicle creating positive autocrine feedback w/in follicle.

Question 14

In the late follicular phase although FSH levels are going down this is actually inducing greater sensitivity in granulosa cells to the impending LH surge. How?

Answer 14

As FSH goes down it induces expression of LH receptors in granulosa and theca cells of dominant follicle

Question 15

With the LH surge…

Answer 15

• stimulates theca cell growth and andgroen production whereby androgen is converted into estradiol in granulosa cell
• stimulates progesterone production in granulosa cells
• Dominant follicle = efficient producer of estradiol

–>increasing estradiol (w/progesterone) evokes (+)feedback on pituitary and hypothalamus inducing surge of LH/FSH, pre-ovulation