Lecture 32 - Chapter 27 - Reproductive System Flashcards
What is oogenesis? When does oogenesis begin?
- Oogenesis is the process of producing female gametes (ova).
- Oogenesis begins during the fetal period.
What are oogonia?
Oogonia are ovarian stem cells that multiply by mitosis and store nutrients.
What happens to primary oocytes during oogenesis? How many primary oocytes does a female have at birth?
- Primary oocytes develop in primordial follicles and begin meiosis but stall in prophase I.
- At birth, a female is presumed to have a lifetime supply of primary oocytes.
When does oogenesis continue after puberty?
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.
What are the products of meiosis I in oogenesis?
After completion of meiosis I, two haploid cells of different sizes are produced: a secondary oocyte and a first polar body.
What happens to the secondary oocyte if it is not penetrated by sperm?
If the secondary oocyte is not penetrated by sperm, it deteriorates.
What happens if the secondary oocyte is penetrated by sperm?
If the secondary oocyte** is** penetrated by sperm, it completes meiosis II, yielding an ovum (functional gamete) and a second polar body.
How does oogenesis differ from spermatogenesis in terms of the number of functional gametes produced?
Oogenesis produces one viable ovum with three polar bodies, while spermatogenesis produces four viable sperm
What are the two consecutive phases of the ovarian cycle?
The two consecutive phases of the ovarian cycle are the:
1. follicular phase (days 1-14)
2. luteal phase (days 14-28).
What triggers the growth of vesicular follicles during the follicular phase?
Rising levels of follicle-stimulating hormone (FSH) trigger the growth of vesicular follicles during the follicular phase.
What happens during ovulation?
- 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.
What happens to the ruptured follicle after ovulation?
The ruptured follicle collapses, and the remaining granulosa cells and internal thecal cells enlarge to form the corpus luteum.
What is the function of the corpus luteum?
The corpus luteum secretes progesterone and some estrogen, which help sustain pregnancy until the placenta takes over.
What happens to the corpus luteum if pregnancy does not occur?
If pregnancy does not occur, the corpus luteum degenerates into a scar tissue called the corpus albicans.
How is the ovarian cycle regulated hormonally?
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.
What is the role of FSH and LH in the ovarian cycle?
- FSH stimulates granulosa cells to release estrogen
- LH stimulates thecal cells to produce androgens, which are converted to estrogens by the granulosa cells.
What is the role of estrogen in the ovarian cycle?
Estrogen promotes the growth and development of the endometrium in preparation for potential implantation of a fertilized ovum.
What is menarche?
Menarche refers to the first occurrence of menstruation, marking the onset of the reproductive capability in females.
What triggers ovulation and the formation of the corpus luteum?
The LH surge triggers ovulation and the formation of the corpus luteum.
How does negative feedback inhibit LH and FSH release?
Rising plasma progesterone and estrogen levels, along with inhibin from the corpus luteum and granulosa cells, inhibit LH and FSH release.
What happens to the amount of FSH and LH if no fertilization occurs?
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.
What are the three phases of the uterine (menstrual) cycle?
The three phases of the uterine cycle are:
1. the menstrual phase
2. the proliferative (preovulatory) phase
3. the secretory (postovulatory) phase
What happens to the stratum functionalis during the menstrual phase?
During the menstrual phase, the stratum functionalis detaches from the uterine wall and is shed, resulting in menstrual flow.
What happens during the proliferative phase?
Rising estrogen levels prompt the generation of a new stratum functionalis layer, enlargement of glands, and an increase in the number of arteries.
What happens during the secretory phase?
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.
What is the main function of mammary glands?
The main function of mammary glands is milk production to nourish newborns.
What are the risk factors for breast cancer?
Factors include hormonal factors, reproductive history, and genetic mutations.
How is breast cancer diagnosed?
Through self-examination, mammography, and diagnostic MRIs for high-risk women.
Recommended that women age 40+ get a mammography every year
Image of how Gonadotropins act during the ovarian cycle
