EXAM #1: ENDOCRINOLOGY OF OB/GYN

Question 1

What are the two main phases of the ovarian cycle? Which is first and which is second?

Answer 1

1) Follicular (phase 1)

2) Luteal (phase 2)

Question 2

What happens during the follicular phase of the ovarian cycle?

Answer 2

1) Follicle development

2) Endometrial proliferation

Question 3

What happens during the luteal phase of the ovarian cycle?

Answer 3

1) Formation of the corpus luteum

2) Endometrial differentiation

Question 4

What hormone predominantes in the follicular phase of the ovarian cycle?

Answer 4

Estrogen

Question 5

What hormone predominantes in the luteal phase of the ovarian cycle?

Answer 5

Progesterone

Question 6

How is GnRH released? Where is GnRH released from?

Answer 6

GnRH is released in a pulsatile fashion from the hypothalamus

Question 7

Overall, what is the concentration of LH and FSH during the ovarian cycle?

Answer 7

Low

Question 8

How does the feedback of estrogen on the hypothalamus/anterior pituitary change throughout the ovarian cycle?

Answer 8

• Generally there is negative feedback

- Mid-cycle i.e. ovulation there is POSITIVE feedback

Question 9

What synthesizes the inhibins?

Answer 9

Granulosa cells of the ovary

Question 10

When is the concentration of Inhibin B the highest?

Answer 10

Follicular phase and just post ovulation

Question 11

What hormone does Inhibin B exert negative feedback on?

Answer 11

FSH

Question 12

When is the concentration of Inhibin A the highest?

Answer 12

Luteal phase

Question 13

Describe how estradiol is produced during the follicular phase of the ovarian cycle.

Answer 13

1) Theca cells synthesize androstenedione in response to LH

2) Graulosa cells= FSH controls the conversion of androstenedione to estradiol

Question 14

In the follicular phase, what do Theca cells synthesize?

Answer 14

Androstenedione

Question 15

What controls the production of androstenedione from theca cells in the follicular phase of the ovarian cycle?

Answer 15

LH

Question 16

After the formation of a mature/dominant follicle in the follicular phase of the ovarian cycle, what change in hormone levels correspond with follicular atresia of the non-dominant follicles?

Answer 16

• Decrease in FSH

- Increase in Inhibin B

Question 17

What is the effect of estrogen on the endometrium?

Answer 17

Proliferation

Question 18

What is the effect of progesterone on the endometrium?

Answer 18

Differentiation

Question 19

At day 14, a surge in _____ causes ovulation?

Answer 19

LH and FSH

Question 20

What is absolutely required for ovulation to occur?

Answer 20

Surge of LH

Question 21

Why can basal body temperature (BBT) be used as an indirect marker of ovulation?

Answer 21

Progesterone causes an increase in basal body temperature

Question 22

What is the corpus luteum?

Answer 22

Temporary endocrine gland in the ovary that secretes estradiol and progesterone

Question 23

How does LH increase the synthesis of progesterone?

Answer 23

1) LH upregulates genes of progesterone synthesis

2) Increased cholesterol uptake for progesterone synthesis

Question 24

How are the ovarian follicle and the corpus luteum related?

Answer 24

Follicle becomes the corpus luteum after ovulation

Question 25

What hormone inhibits the HPG axis during the luteal phase? How does this negative feedback compare to the follicular phase?

Answer 25

- Inhibin A | - Negative feedback is more intense

Question 26

What does the corpus luteum become once it has regressed?

Answer 26

Corpus albicans

Question 27

What is "hatching" in implantation and formation of the placenta?

Answer 27

Breakdown of the zona pellucida

Question 28

What is "apposition" in implantation and formation of the placenta?

Answer 28

Trophoblast contact with the endometrium in the uterus

Question 29

What is " adhesion" in implantation and formation of the placenta?

Answer 29

Integrin mediated attachment of the trophoblast (embryo) and decidua cells of the endometrium

Question 30

What happens in "invasion" during implantation and formation of the placenta?

Answer 30

1) Trophoblast becomes cytotrophoblast and syncytiotrophoblast 2) Syncytiotrophoblasts send out protrusions that invade the endometrium

Question 31

What happens after the syncytiotrophoblasts invade the endometrium?

Answer 31

1) Syncytiotrophoblasts invade maternal veins and arteries | 2) Primary chorionic villi form

Question 32

If fertilization occurs, what hormone is produced to maintain pregnancy?

Answer 32

hCG is produced by the syncitiotrophoblast cells of the placenta

Question 33

What does hCG bind to? What does hCG maintain?

Answer 33

- Binds LH receptors | - Maintains the corpus luteum

Question 34

After the first 8 weeks of pregnancy, what secretes progesterone and estrogen?

Answer 34

Syncitiotrophoblast cells of the placenta

Question 35

What is hPL?

Answer 35

Human Placental Lactogen

Question 36

What are the functions of hPL?

Answer 36

1) Fetal metabolism | 2) Fetal growth and development

Question 37

What secretes hPL?

Answer 37

Syncitiotrophoblast cells of the placenta

Question 38

What aside from the hypothalamus secreted CRH? When is this secreted?

Answer 38

- Syncitiotrophoblasts and trophoblasts | - Dramatic increase prior to delivery

Question 39

What is the key role of the androgens/ DHEA in pregnancy?

Answer 39

This is the substrate for estrogen synthesis

Question 40

Where does DHEA come from?

Answer 40

1) Maternal adrenal gland 2) Fetal adrenal gland 3) Fetal liver