Chapter 5: Implantation and Placental Development

Question 1

How many OOCYTES does the ovary contain AT BIRTH?`

Answer 1

2 million

Question 2

How many FOLLICLES are present at PUBERTY? This number is depleted at a rate of approximately _________ follicles per month until age 35.

Answer 2

400, 000

1000 follicles/month

Question 3

How many follicles are normally released during the female reproductive life?

Answer 3

400

Question 4

Which is TRUE?

a. During each ovarian cycle, a group of antral follicles known as cohort, begins a phase of synchronous growth based on their maturation state during the LH rise in the early luteal phase of the current cycle.
b. During each ovarian cycle, a group of antral follicles known as cohort, begins a phase of semisynchronous growth based on their maturation state during the FSH rise in the late luteal phase of the previous cycle.
c. During each ovarian cycle, a group of antral follicles known as cohort, begins a phase of semisynchronous growth based on their maturation state during the FSH decline in the late luteal phase of the current cycle.
d. During each ovarian cycle, a group of antral follicles known as cohort, begins a phase of synchronous growth based on their maturation state during the LH decline in the early luteal phase of the previous cycle.

Answer 4

b. During each ovarian cycle, a group of antral follicles known as cohort, begins a phase of SEMIsynchronous growth based on their maturation state during the FSH RISE in the LATE luteal phase of the PREVIOUS cycle.

Question 5

True or false. Only follicles progressing to the selection window of the ovarian cycle develop the capacity to produce estrogen.

Answer 5

True.

FSH increase leading to further follicular development is called the selection window of the ovarian cycle. Only follicles progressing to this stage develop the capacity to produce estrogen.

Question 6

Exclusive site of FSH receptor expression.

Answer 6

granulosa cells

Question 7

True or false. The follicle within the cohort that is most responsive to LH is likely to be the first to produce estradiol and initiate expression of FSH receptors.

Answer 7

FALSE. The follicle within the cohort that is most responsive to FSH is likely to be the first to produce estradiol and initiate expression of LH receptors.

Question 8

True or false. The drop in LH levels is responsible for the failure of other follicles to reach preovulatory status (Graafian follicle stage) during any one cycle.

Answer 8

FALSE. The drop in FSH levels is responsible for the failure of other follicles to reach preovulatory status (Graafian follicle stage) during any one cycle.

Estradiol and inhibin B rise results in decline of FSH.
During the Graafian follicle stage, 95% of plasma estradiol is secreted by the dominant follicle - the one destined to ovulate.

Question 9

What is the 2-cell, 2-gonadotropin principle of ovarian steroid hormone production?

Answer 9

Basically:
theca cell = LH receptors
granulosa cells = FSH receptors

FOLLICULAR PHASE

Theca cells express LH receptors, and cholesterol is converted into androstenedione. Androstenedione diffuses into adjacent granulosa cells. FSH controls the conversion of androstenedione to estradiol through CYP 450 aromatase.

LUTEAL PHASE/PREGNANCY (after ovulation)

Corpus lute forms and both the Granulosa-lutein cells and theca-lutein cells respond to LH (because both of them have LH receptors). Aside from the androstenedione being converted to estradiol, cholesterol (particularly LDL) is converted into progesterone.

LH and hCG binds to the same LH-hCG receptor. If pregnancy occurs, hCG rescues the corpus lute through the shared receptor.

Question 10

LH secretion peaks at ______ hours before ovulation.

Answer 10

10-12

Gonadotropin surge secondary to estrogen section is a precise predictor of ovulation.

Question 11

What do you call the process where cumulus cells lose contact with one another and move outward from the oocyte along the hyaluronan polymer?

Answer 11

Expansion

Through this LH-induced remodeling of the ovarian extracellular matrix, the mature oocyte can be released.

Question 12

The corpus luteum develops from the remains of the:

a. Antral follicle
b. Graafian follicle
c. Cumulus oophorum

Answer 12

b. Graafian follicle.

The process is called luteinization.
During luteinization, the basement membrane between theca cells and granulosa cells breaks down, neovascularization occurs and the cells undergo hypertrophy and increase capacity to synthesize hormones.

Question 13

This is the primary luteotrophic factor responsible for corpus luteum maintenance.

Answer 13

LH

LH injections can extend the life of CL by 2 weeks.

Question 14

True or false. The hormone secretion pattern of the corpus luteum is similar to that of the follicle.

Answer 14

FALSE.

corpus luteum production of progesterone occurs as a response to hCG.
Granulosa-lutein cell production of progesterone is through enhances steroidogenesis through LDL-derived cholesterol.

Question 15

In the absence of pregnancy, the corpus luteum will rapidly regress ____ days after ovulation via apoptosis.

Answer 15

9-11 days

The corpus luteum is a transient endocrine organ.

Question 16

Most important factor in endometrial recovery following menstruation

Answer 16

Follicular-phase estradiol

Question 17

True or False: Re-epithelialization of the endometrium begins even before menstrual bleeding has ceased.

Answer 17

TRUE

By the 5th day of menses, the epithelium has been restored.

Question 18

BONUS LEARNING

Answer 18

Epithelial cell growth is regulated by the epidermal growth factor and TGFa.

Stromal cells proliferate through paracrine and autocrine actions of estrogen and greater local levels of fibroblast growth factor-9.

Estrogens raise local production of VEGF which promotes angiogenesis through basal cell elongation in the basalis.

Question 19

Describe the preovulatory endometrium in terms of:
thickness
glands
blood vessels
mitotic figures

Answer 19

PREOVULATORY/EARLY PROLIFERATIVE ENDOMETRIUM

• less than 2mm thick
• glands are narrow, tubular structures that pursue almost a straight and parallel course from the basalts layer toward the EM cagvity
• blood vessels are numerous and prominent
• mitotic figures are identified by the 5th day, persists until day 16-17

Question 20

Describe the late proliferative phase endometrium:
glands and storm of functionalism vs basalis layer
thickness

Answer 20

LATE PROLIFERATIVE ENDOMETRIUM

• EM thickens (due to the glandular hyperplasia and augmented stroll ground substance: edema and proteinaceous material)
• functionalis: loose stroma, glands widely separated
• basalis: denser stroma, glands crowded

Midcycle: glandular epithelium becomes taller and pseudostratified, surface epithelial cells acquire villi

Question 21

Ovulatio separates which phases of the menstrual cycle

Answer 21

Follicular and luteal phase

Question 22

This event separates the follicular qnd lute phase of the menatrual cycle

Answer 22

Ovulation

Question 23

Thisbis the primary luteotrophic factor responsible for corpus luteum maintenance

Answer 23

LH

Question 24

Corpus luteum develops from _________ in a porcess called luteinization

Answer 24

Graafian follicle

Question 25

How does hormone secretion pattern of CL differ from that of a follicle?

Answer 25

1. Greater capacity of granulosa-lutein cells to produce progesterone from enhanced LDL-derived cholesterol
2. CL continues to produce progesterone in response to hCG (ovarian progesterkne production peaks at 25-50mg/day during thr midluteal phase)

Question 26

In the absence of pregnancy, the CL undergoes apoptosis how may days after ovulation?

Answer 26

9-11 days postovulation

Question 27

Name the endometrial changes seen durig the window of implantation, which happens o day _____ postovovulation

Answer 27

20-24 days

1. Spiral artery lengthening