Lecture 32 - Chapter 27 - Reproductive System

Question 1

What is oogenesis? When does oogenesis begin?

Answer 1

1. Oogenesis is the process of producing female gametes (ova).
2. Oogenesis begins during the fetal period.

Question 2

What are oogonia?

Answer 2

Oogonia are ovarian stem cells that multiply by mitosis and store nutrients.

Question 3

What happens to primary oocytes during oogenesis? How many primary oocytes does a female have at birth?

Answer 3

1. Primary oocytes develop in primordial follicles and begin meiosis but stall in prophase I.
2. At birth, a female is presumed to have a lifetime supply of primary oocytes.

Question 4

When does oogenesis continue after puberty?

Answer 4

After puberty, each month a few primary oocytes are activated, and one from this group is selected to become the dominant follicle that resumes meiosis I.

Question 5

What are the products of meiosis I in oogenesis?

Answer 5

After completion of meiosis I, two haploid cells of different sizes are produced: a secondary oocyte and a first polar body.

Question 6

What happens to the secondary oocyte if it is not penetrated by sperm?

Answer 6

If the secondary oocyte is not penetrated by sperm, it deteriorates.

Question 7

What happens if the secondary oocyte is penetrated by sperm?

Answer 7

If the secondary oocyte** is** penetrated by sperm, it completes meiosis II, yielding an ovum (functional gamete) and a second polar body.

Question 8

How does oogenesis differ from spermatogenesis in terms of the number of functional gametes produced?

Answer 8

Oogenesis produces one viable ovum with three polar bodies, while spermatogenesis produces four viable sperm

Question 9

What are the two consecutive phases of the ovarian cycle?

Answer 9

The two consecutive phases of the ovarian cycle are the:
1. follicular phase (days 1-14)
2. luteal phase (days 14-28).

Question 10

What triggers the growth of vesicular follicles during the follicular phase?

Answer 10

Rising levels of follicle-stimulating hormone (FSH) trigger the growth of vesicular follicles during the follicular phase.

Question 11

What happens during ovulation?

Answer 11

• Rising levels of luteinizing hormone (LH) cause the ovary wall to rupture, expelling the secondary oocyte.
• The LH surge triggers the primary oocyte to complete meiosis I, becoming a secondary oocyte, which then enters meiosis II.

Question 12

What happens to the ruptured follicle after ovulation?

Answer 12

The ruptured follicle collapses, and the remaining granulosa cells and internal thecal cells enlarge to form the corpus luteum.

Question 13

What is the function of the corpus luteum?

Answer 13

The corpus luteum secretes progesterone and some estrogen, which help sustain pregnancy until the placenta takes over.

Question 14

What happens to the corpus luteum if pregnancy does not occur?

Answer 14

If pregnancy does not occur, the corpus luteum degenerates into a scar tissue called the corpus albicans.

Question 15

How is the ovarian cycle regulated hormonally?

Answer 15

The release of gonadotropin-releasing hormone (GnRH) stimulates the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which act on the ovaries to stimulate follicle growth, maturation, and hormone production.

Question 16

What is the role of FSH and LH in the ovarian cycle?

Answer 16

• FSH stimulates granulosa cells to release estrogen
• LH stimulates thecal cells to produce androgens, which are converted to estrogens by the granulosa cells.

Question 17

What is the role of estrogen in the ovarian cycle?

Answer 17

Estrogen promotes the growth and development of the endometrium in preparation for potential implantation of a fertilized ovum.

Question 18

What is menarche?

Answer 18

Menarche refers to the first occurrence of menstruation, marking the onset of the reproductive capability in females.

Question 19

What triggers ovulation and the formation of the corpus luteum?

Answer 19

The LH surge triggers ovulation and the formation of the corpus luteum.

Question 20

How does negative feedback inhibit LH and FSH release?

Answer 20

Rising plasma progesterone and estrogen levels, along with inhibin from the corpus luteum and granulosa cells, inhibit LH and FSH release.

Question 21

What happens to the amount of FSH and LH if no fertilization occurs?

Answer 21

If no fertilization occurs, the corpus luteum degenerates, leading to a decrease in estrogen and progesterone levels, which ends the blockage of FSH and LH secretion, and the cycle starts over again.

Question 22

What are the three phases of the uterine (menstrual) cycle?

Answer 22

The three phases of the uterine cycle are:
1. the menstrual phase
2. the proliferative (preovulatory) phase
3. the secretory (postovulatory) phase

Question 23

What happens to the stratum functionalis during the menstrual phase?

Answer 23

During the menstrual phase, the stratum functionalis detaches from the uterine wall and is shed, resulting in menstrual flow.

Question 24

What happens during the proliferative phase?

Answer 24

Rising estrogen levels prompt the generation of a new stratum functionalis layer, enlargement of glands, and an increase in the number of arteries.

Question 25

What happens during the secretory phase?

Answer 25

Rising progesterone levels from the corpus luteum cause the functional layer to become a secretory mucosa, glands enlarge and secrete nutrients, and a cervical mucus plug is formed.

Mucus plug is formed to block other sperm from entering.

Question 26

What is the main function of mammary glands?

Answer 26

The main function of mammary glands is milk production to nourish newborns.

Question 27

What are the risk factors for breast cancer?

Answer 27

Factors include hormonal factors, reproductive history, and genetic mutations.

Question 28

How is breast cancer diagnosed?

Answer 28

Through self-examination, mammography, and diagnostic MRIs for high-risk women.

Recommended that women age 40+ get a mammography every year

Question 29

Image of how Gonadotropins act during the ovarian cycle

Answer 29