Reproductive System Unit Lesson 3: Ovarian Cycle and Birth

Question 1

What is the ovarian cycle?

Answer 1

The cyclic process by which eggs are matured and released

Question 2

What is the uterine cycle?

Answer 2

The cyclic process by which the lining of the uterus is prepared, maintained, and discarded

Question 3

What do ovaries contain?

Answer 3

Numerous follicles, which each contain an immature oocyte

Question 4

What are follicles?

Answer 4

Follicles are anatomical structures that contain immature oocytes, present at birth. Each has the potential of maturing and becoming a mature oocyte (egg).

women have around 700,000 follicles, but only around 400 mature

Question 5

What occurs at the beginning of the Ovarian Cycle?

Answer 5

Several follicles will attempt to mature at the same time, however only 1 typically matures and will be released per month

Question 6

What are the 3 stages of Follicle development?

Answer 6

Primary follicle, secondary follicle, tertiary follicle (also known as vesicular follicle or graafian follicle)

Question 7

What occurs at the primary follicle?

Answer 7

Contains primary oocyte and produces estrogen

Question 8

What occurs at the secondary follicle?

Answer 8

Contains primary oocyte which is filled with follicular fluid, causing its size to balloon. It releases estrogen and some progesterone

Question 9

What occurs at the tertiary follicle?

Answer 9

Contains primary oocyte and is surrounded by large amounts of follicular fluid. The large size causes it to balloon out of the ovary’s surface

Question 10

What can the Ovarian cycle be separated into? (phases)

Answer 10

Follicular and Luteal phases

Question 11

What occurs at the Luteal phase?

Answer 11

1. Luteinizing hormone promotes development of corpus luteum which will secrete progesterone and some estrogen
2. Levels of progesterone in the blood exert negative feedback on secretion of LH causing corpus luteum to begin degeneration

Question 12

What occurs at the Follicular phase?

Answer 12

1. Follicle stimulating hormone (FSH) is released by the anterior pituitary gland, which promotes the development of follicles in the ovary
2. Follicles secrete estrogen and progesterone in the bloodstream which produces negative feedback of FSH production at the pituitary
3. Increase in estrogen causes large amounts of GnRH to be secreted from the hypothalamus which leads to a surge of Luteinizing hormone (LH) from the anterior pituitary, causing ovulation to occur

Question 13

What is endometrium?

Answer 13

Thin layer of tissue that lines the uterus

over the course of 28 days, this layer of tissue undergoes changes that coincide with the ovarian cycle

Question 14

What are the stages of the uterine cycle? (28 days)

Answer 14

Menstruation (day 1 - 5)
Proliferative Phase (day 6 - 13)
Ovulation (day 14)
Secretory Phase (day 15 - 28)