Preparation for Pregnancy and Ovulation

Question 1

When does ovulation occur in the ovarian cycle?

Answer 1

Day 14

Question 2

What role does LH and FSH play in ovulation?

Answer 2

They stimulate ovulation by rising, they are secreted from the anterior pituitary

Question 3

What is the source of progesterone in the ovarian cycle?

Answer 3

Thecal cells of the Graafian follicle

Question 4

What is the source of estrogen in the follicular phase and what is it responsible for?

Answer 4

Granulosa cells and they are responsible for the proliferation phase of the endometrium

Question 5

What components of the tertiary follicle form the corpus luteum?

Answer 5

Residual Theca and Granulosa cells

Question 6

What role does inhibin play in the menstrual cycle?

Answer 6

Inhibin is released by granulosa cells and inhibits secretion of gonadotropins such as FSH

Question 7

What factors contribute to vasoconstriction of spiral arteries?

Answer 7

Prostaglandins and decreasing levels of estrogen and progesterone

Question 8

What is the major factor that leads to menopause?

Answer 8

No more eggs to be ovulated so a decrease in the production of estrogen and progesterone

Question 9

Describe the Graafian follicle immediately prior to ovulation.

Answer 9

It is bulging out like a blister on the ovary. The antrum is large and the oocyte is surrounded by zona pellucida, corona radiata and stratum granulosum as well as thecal cells.

Question 10

What are the substages of Ovarian cycle?

Answer 10

Follicular phase: days 1-14
Ovulation 14
Luteal phase

Question 11

What are the substages of endometiral cycle?

Answer 11

Menstrual phase day 1-4/5
Proliferation phase days 4/5-14
Secretory phase days 15-28

Question 12

What occurs in the follicular stage of ovarian cycle?

Answer 12

It is days 1-14 and this is where development of the graafian follicle and secondary oocyte occur. Development of graafian follicle is under control of FSH

Question 13

What occurs during ovulation in the ovarian cycle?

Answer 13

Occurs on day 14, and is stimulated by a rise in FSH and sharp rise in LH. The egg is released from the graafian follicle.

Question 14

What occurs during the luteal phase of the ovarian cycle?

Answer 14

Estrogen and progesterone are secreted from the left over thecal and granulosa cells of the Graafian follicle. Breakdown of membrana granulosa allows angiogenesis. The granulosa cells are luteinized forming corpus luteum.

Question 15

What is necessary to maintain the implantation of the fertilized oocyte?

Answer 15

Progesterone and estrogen

Question 16

What occurs during the luteal phase if fertilization does not occur?

Answer 16

The CL regresses and progesterone and estrogen decrease resulting in the menstrual phase. Eventually the corpus luteum forms the corpus albicans due to granulosa lutein cells being replaced with collagenous scar tissue.

Question 17

If fertilization occurs in the luteal phase what happens to the CL?

Answer 17

HCG from placental tissues maintains a functional CL, granulosa luatein cells are relaced by thecal lutein cells and the CL remains functional for few months of pregnancy.

Question 18

What happens during the menstrual phase of the endometrial cycle?

Answer 18

Endometrial build up from previous cycle sloughs off resulting in flow. Menstruation begins with vasoconstriction of spiral arteries followed by local ischemia.

Question 19

What occurs during the proliferation phase of endometrial cycle?

Answer 19

Endometrium thickness is increased from 1-2mm to 8-10 mm by day 14 blood vessels and glands grow with it.
Proliferation phase due to increasae in levels of estrogen from the granuloa cells of ovarian follicle. Sharp rise in estrogen at the end of the phase.

Question 20

What occurs during the secretory phase of endometrial cycle?

Answer 20

Levels of estrogen decrease and endometrial growth stops. Spiral arterioles expand and heavily vascularize the area. Secretory phase is controlled by rising levels of progesterone from the granulosa and thecal cells.

Question 21

How long after ovulation does implantation occur?

Answer 21

7 days

Question 22

During the menstrual cycle before ovulation has occured what stage is the oocyte in?

Answer 22

Diplotene stage of prophase I