Reproductive Cyclicity (Chapter 8)

Question 1

Which hormone is responsible for luteinization?

Answer 1

LH (luteinizing hormone)

Question 2

Does progesterone have a positive or negative feedback on the hypothalamus (GnRH)?

Answer 2

Negative

Question 3

What causes a drop in progesterone levels, and what effect does that have on LH, FSH, and GnRH?

Answer 3

Luteolysis (prostaglandin), which causes an increase in GnRH and an subsequent increase in FSH and LH

Question 4

What specifically happens to FSH and LH during proestrual follicular development?

Answer 4

[Inhibin] increases, causing a decrease in FSH

[Estradiol] increases, causing a preovulatory LH surge

Question 5

What are the two feedbacks that estradiol has?

Answer 5

Negative feedback on FSH

Positive feedback on the Surge Center (LH)

Question 6

What hormone stimulates the surge in LH?

Answer 6

GnRH

Question 7

Why does FSH have a lower and wider peak in concentration during estrus when compared to LH?

Answer 7

FSH is being inhibited by Inhibin (low peak)

The half-life of FSH is longer (wide)

Question 8

When a follicle gets bigger, what does it produce more of to block the growth of the other follicles?

Answer 8

Inhibin

Question 9

What does FSH prevent, how do we over ride Inhibin and what does this cause?

Answer 9

FSH prevents atresia

We can give shots of FSH to over ride Inhibin, which will cause super ovulation

Question 10

What is super ovulation and how do we achieve this?

Answer 10

Its all follicles, that a female can naturally recruit, becoming dominant
We can achieve this through FSH shots

Question 11

(T/F) A single cow has a set number of follicles she can recruit

Answer 11

True

Question 12

(T/F) We can get embryos from pregnant animals

Answer 12

True, they continue to have follicles even after pregnancy has started

Question 13

What happens to the LH pulse during the LH surge?

Answer 13

The frequency of the pulses exceeds the half-life of LH, causing the surge

Question 14

The theca interna cells only has receptors for what type of hormone and what is it responsible for converting?

Answer 14

LH receptors

Converts cholesterol into testosterone

Question 15

What cell type has only FSH receptors and what is it responsible for converting?

Answer 15

Granulosal cells

Converts testosterone into estradiol (via aromatase)

Question 16

What two cells are apart of the Two Cell Model?

Answer 16

Granulosal cells and theca interna cells

Question 17

Estradiol cause what three functions to increase in the brain?

Answer 17

Lordosis (heat stance), Phonation (vocalization), and physical activity

Question 18

What are some functions in the reproductive tract that are increased due to estradiol?

Answer 18

Blood flow, edema in tissues, mucosal secretion, smooth muscle motility

Question 19

What two follicular characteristics are needed for ovulation?

Answer 19

Increased follicular pressure

Weakening of follicular wall

Question 20

What enzyme degrades the matrix of the follicular wall and what shift in hormones is responsible for this?

Answer 20

Collagenase

Shift from estrogen to progesterone (caused by LH surge)

Question 21

The removal of what via the breakdown of what is triggered by the LH surge and makes fertilization possible?

Answer 21

Meiotic inhibition

Breakdown of gap junction between granulosal cells and oocyte