Ovarian Cycle

Question 1

what synthesizes Gonadotropin- releasing hormone

Answer 1

neurosecretory cells in the hypothalamus

Question 2

what do Gonadotropin- releasing hormone stimulate

release of

Answer 2

• Follicle-stimulating hormone (FSH) stimulates the development of ovarian follicles and the production of estrogen by the follicular cells.
• Luteinizing hormone (LH) serves as the “trigger” for ovulation and stimulates the theca interna cells and corpus luteum to produce progesterone

Question 3

what does FSH stimulate the growth of

Answer 3

15 to 20 primary follicles. it doesnt promote development but without it, these primary follicles die and become atretic

Question 4

what happens when a follicle becomes atretic

Answer 4

the oocyte and surrounding follicular cells degenerate are replaced by connective tissue, forming a corpus atreticum

Question 5

FSH also situmulates maturation of ____________ surrounding the oocyte

Answer 5

follicular (granulosa) cells

Question 6

what mediates proliferation of follicular cells

Answer 6

by growth differentiation factor 9, a member of the transforming growth factor-β (TGFβ) family

Question 7

what is the function of

a) theca interna
b) granulosa cells

Answer 7

a) atheca interna cells produce androstenedione and testosterone
b) granular cells convert these hormones to estrone and 17 βestradiol

Question 8

During this menstrual cycle, the uterine endometrium passes through three stages ______

Answer 8

1. Follicular or proliferative phase
2. Secretory or progestational phase
3. Menstrual phase

Question 9

As a result of this estrogen production, the uterine endometrium enters the _____________

Answer 9

follicular or proliferative phase

Question 10

what causes cervical mucus thinning and what is its purpose

Answer 10

As a result of estrogen and to allow passage of sperm

Question 11

what do the follicular cells secrete due to estrogen production

Answer 11

inhibin

Question 12

due to estrogen production, what does the anterior lobe of the pituitary gland secrete

Answer 12

LH

Question 13

when does the proliferative phase begin

Answer 13

begins at the end of the menstrual phase

Question 14

what happens during the proliferation phase

Answer 14

• Glands proliferation

* Gland, spiral arteries and stroma grow toward lumen

Question 15

proliferative phase is under the influence of ________, and parallels growth of the ____________

Answer 15

Estrogen

ovarian follicles

Question 16

At midcycle, what does surge in LH cause

Answer 16

• Elevates concentrations of maturation-promoting factor, causing oocytes to complete meiosis I and initiate meiosis II.
• Causes graafian follicular cells rupture and ovulation.
• Stimulates production of progesterone by remaining follicular cells (luteinization)

Question 17

what also happens in the midcycle

Answer 17

surface of the ovary begins to bulge locally, and at the apex, an avascular spot, the stigma, appears

Question 18

what does a high concentration of LH cause

Answer 18

increases collagenase activity, resulting in digestion of collagen fiber surrounding the follice

Question 19

what does prostaglandins increase in response to the LH surge cause

Answer 19

cause local muscular contractions in the ovarian wall

Question 20

what happens shortly before ovulation

Answer 20

fimbriae of the uterine tube sweep over the surface of the ovary and the tube itself begins to contract rhytmically

Question 21

what is the function of contraction of the uterine tube

Answer 21

send the oocyte which together with its surrounding granulosa cells from the region of the cumulus oophorus breaks free (ovulation) and floats out of the ovary

Question 22

After ovulation, granulosa cells remaining in the wall of the ruptured follicle, together with cells from the theca interna are vascularized by surrounding vessels forming ___________

Answer 22

Corpus Hemorrhagicum

Question 23

what causes Corpus Hemorrhagicum to change to Corpus Luteum

Answer 23

it develops a yellowish pigment due to LH

Question 24

what does the corpus luteum secrete

Answer 24

estrogens and progesterone

Question 25

what does progesterone and some estrogen then cause after their secretion

Answer 25

causes the uterine mucosa to enter the progestational or secretory stage in preparation for implantation of the the embryo

Question 26

what happens once the oocyte is in the uterine tube

Answer 26

it is propelled by peristaltic muscular contractions of the tube and by cilia in the tubal mucosa with the rate of the transport regulated by the endocrine status during and after ovulation

Question 27

what causes the shrinkage of the corpus luteum

Answer 27

degeneration of lutean cells (luteolysis) forming

Question 28

what does the corpus luteum form after shrinking due to no fertilization

Answer 28

forms a mass of fibrotic scar tissue- the corpus albicans

Question 29

what happens when the corpus luteum stops developing

Answer 29

progesterone production decreases, precipitating menstrual bleeding