Non-pregnant female reproduction

Question 1

Q: What are the reproductive functions of the female reproductive system?

Answer 1

1. Produce ova (oogenesis):
   
   • Creation of egg cells in the ovaries.
2. Provide site for fertilization (oviducts):
   
   • Oviducts, or fallopian tubes, where sperm meets the egg.
3. Maintaining the fetus (uterus) and expelling it at the end of gestation (vagina):
   
   • The uterus supports fetal development, and the vagina is the birth canal.
4. Produce sex steroids - estrogen and progesterone:
   
   • Hormones that regulate the reproductive cycle and secondary sexual characteristics.

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Question 2

Q: What are the primary reproductive organs (gonads) in the female reproductive system and their functions?

Answer 2

• Ovaries:
  
  • Produce ova through oogenesis.
  • Secrete sex hormones (estrogen and progesterone).
• Fallopian Tubes (Oviducts):
  
  • Site of fertilization.
• Uterus:
  
  • Maintains and supports the fetus during gestation.
  • Comprised of endometrium (glandular epithelium), myometrium (smooth muscle), and outer connective tissue.
• Vagina:
  
  • Serves as the birth canal.
  • Passageway for menstrual flow and intercourse.

Diagram Labels:
- Mammary glands
- Uterus
- Cervix
- Vagina
- Urethra
- Clitoris
- Labium majus and minus
- Ovary
- Fallopian tube
- Uterine cavity
- Endometrium
- Myometrium
- Uterine artery

Question 3

Q: How is the female reproductive cycle regulated and what are its key phases?

Answer 3

• Release of Ova: Intermittent, occurring in a cyclic pattern.
• Cycle Regulation: Hormonal regulation controls the cycle.

Key Phases:
1. Ovulation:
- Release of an egg from the ovary.

2. Menstruation:
   
   • Shedding of the uterine lining if fertilization does not occur.

Cycle Preparation:
- No Fertilization:
- The cycle repeats itself, preparing for the next potential fertilization.

• Fertilization:
  
  • The female system adapts to nurture and protect the developing fetus.

Question 4

Q: What occurs during oogenesis in utero?

Answer 4

• Primordial Germ Cells:
  
  • Undifferentiated primordial germ cells in fetal ovaries divide mitotically to produce 6-7 million oogonia by the fifth month of gestation.
• Meiotic Division:
  
  • Oogonia begin the early steps of the first meiotic division but do not complete it.
• Result:
  
  • The oogonia become primary oocytes.

Stages of Oogenesis Diagram:
- Oogonium: Initial germ cell.
- Mitotic Proliferation Prior to Birth: Oogonia undergo mitotic divisions.
- Primary Oocytes: Result from the oogonia and are arrested in the first meiotic division.
- Chromosomes in Each Cell: Primary oocytes have 46 chromosomes (diploid number; doubled strands).

Question 5

Q: What occurs during oogenesis before and after birth?

Answer 5

Before Birth:
- Primary Oocyte:
- Surrounded by a single layer of granulosa cells.
- Forms a primordial (primary) follicle.

After Birth:
- Ovaries at Birth:
- Act as a reservoir, holding all the ova throughout reproductive life.

• Primary Oocytes:
  
  • Of the 2 million primary oocytes present at birth, only 400 will mature and release ova.
• Fate of Primary Follicles:
  
  • They either reach maturity and ovulate or degenerate and form scar tissue (atresia).

Diagram Labels:
- Primary Follicles (40 μm):
- Primary Oocyte
- Single Layer of Granulosa Cells
- Follicular Cells:
- Surround the oocyte.
- Zona Pellucida:
- Clear structure around the oocyte.
- Nucleus and Cytoplasm:
- Components of the oocyte visible in the late primary follicle stage.

Question 6

Q: What is the process of ovum formation from puberty to menopause?

Answer 6

Puberty to Menopause:
- Follicles start developing into secondary follicles on a cyclical basis.

Steps:
1. Primary Oocytes:
- Arrested in the first meiotic division (46 chromosomes; doubled strands).

2. Enlarged Primary Oocyte:
   
   • One primary oocyte reaches maturity and is ovulated about once a month until menopause.
3. First Meiotic Division (Completed Prior to Ovulation):
   
   • Produces a secondary oocyte (23 chromosomes; doubled strands) and a first polar body.
4. Secondary Oocyte:
   
   • Arrested in the second meiotic division until fertilization.
5. Second Meiotic Division (Completed After Fertilization):
   
   • Produces a mature ovum (23 chromosomes; single strands) and a second polar body.
   • Polar bodies degenerate.

Diagram Labels:
- Meiosis: Process of cell division.
- Polar Bodies: Byproducts of oocyte development.
- Chromosome Numbers:
- Primary oocyte: 46 chromosomes (doubled strands).
- Secondary oocyte: 23 chromosomes (doubled strands).
- Mature ovum: 23 chromosomes (single strands).
- Fertilized Ovum: Combination of 23 chromosomes from the ovum and 23 chromosomes from the sperm, resulting in 46 chromosomes.

Question 7

Q: What are the stages of ovum formation from prenatal development to post-fertilization?
A:

Answer 7

Stages:
1. Pre-natal:
- Oogonium (+ granulosa cells):
- Undergoes mitosis and growth to form the primary oocyte.
- By birth, 1-2 million primary oocytes are present.

2. Puberty:
   
   • Primary Oocyte (2n, locked in prophase I):
     
     • Starts meiosis I.
     • About 300,000 primary oocytes remain at puberty.
3. Fertilization:
   
   • Secondary Oocyte (n, locked in metaphase II):
     
     • Completes meiosis I just before ovulation and starts meiosis II.
     • About 400 oocytes will reach this stage.
     • Completes meiosis II after fertilization.
4. Post-Fertilization:
   
   • Ovum (n):
     
     • Formed after the completion of meiosis II.
     • The result is one mature ovum and polar bodies that degenerate.

Diagram Labels:
- Oogenesis:
- Primary oocyte (2n)
- Secondary oocyte (n)
- Polar body and ovum (n)

• Spermatogenesis (for comparison):
  
  • Primary spermatocyte (2n)
  • Secondary spermatocyte (n)
  • Spermatid (n)
  • Sperm (n)

Key Chromosome Numbers:
- Oogonium: 2n (diploid)
- Primary Oocyte: 2n (diploid)
- Secondary Oocyte: n (haploid)
- Ovum: n (haploid)

Question 8

Q: What are the key differences between oogenesis and spermatogenesis?

Answer 8

Process:
- Spermatogenesis:
- Location: Occurs entirely in the testes.
- Meiotic Divisions: Equal division of cells.
- Germ Line Epithelium: Involved in gamete production.

• Oogenesis:
  
  • Location: Occurs mostly in the ovaries.
  • Meiotic Divisions: Unequal division of cytoplasm.
  • Germ Line Epithelium: Not involved in gamete production.

Gametes:
- Spermatogenesis:
- Number Produced: Four sperm.
- Size of Gametes: Sperm are smaller than spermatocytes.

• Oogenesis:
  
  • Number Produced: One ovum (plus 2-3 polar bodies).
  • Size of Gametes: Ova are larger than oocytes.

Timing:
- Spermatogenesis:
- Duration: Uninterrupted process.
- Onset: Begins at puberty.
- Release: Continuous.
- End: Lifelong (but reduces with age).

• Oogenesis:
  
  • Duration: In arrested stages.
  • Onset: Begins in the fetus (prenatal).
  • Release: Monthly from puberty (menstrual cycle).
  • End: Terminates with menopause.

Question 9

Flashcard for Ovarian/Uterine Cycle

Q: What are the key phases of the ovarian/uterine cycle and their characteristics?
A:

Answer 9

Phases of the Ovarian/Uterine Cycle:

1. Follicular Phase (Proliferative Phase) - Estrogen Dominant:
   
   • Function:
     
     • Produces mature follicles ready for ovulation at mid-cycle.
     • Uterine lining rebuilds and thickens.
2. Luteal Phase (Secretory Phase) - Progesterone Dominant:
   
   • Function:
     
     • Presence of the corpus luteum post-ovulation.
     • Prepares the reproductive tract for pregnancy if fertilization has occurred.

Cycle Interruption and Termination:
- Interrupted by pregnancy.
- Terminated at menopause.

Cycle Duration:
- Average cycle lasts 28 days but varies among women.

Diagram Labels:
- Cycle Phases:
- Pre-ovulation: Follicular phase (ovarian cycle), proliferative phase (uterine cycle).
- Post-ovulation: Luteal phase (ovarian cycle), secretory phase (uterine cycle).
- Ovulation: Mid-point of the cycle.

Question 10

Q: What are the key characteristics of the follicular and luteal phases of the ovary?

Answer 10

Follicular Phase:
- Maturation of the Primary Follicle:
- An essential step prior to ovulation.
- 6-10 follicles per cycle undergo this process.
- The fastest growing follicle becomes dominant while others degenerate.

• Phases of Follicle Development:
  
  • Primordial Follicle -> Primary Follicle -> Secondary Follicle
  • Preantral Follicle -> Early Antral Follicle
  • Transition from gonadotropin-independent phase (intraovarian regulations) to gonadotropin-responsive phase (acquisition of FSH-dependence).

Luteal Phase:
- Ovulation:
- The release of the mature ovum from the dominant follicle.

• Formation of Corpus Luteum:
  
  • Occurs after ovulation.
  • The corpus luteum forms from the remnants of the Graafian follicle and secretes hormones to prepare the reproductive tract for pregnancy.

Diagram Labels:
- Follicular Development:
- Antral Follicle -> Graafian Follicle -> Ovulation -> Corpus Luteum
- Hormonal Phases:
- Gonadotropin-Dependent Phase:
- FSH-Dependence -> LH-Dependence
- Selection -> Ovulation -> Luteinization

Question 11

Q: What is the role of hormones in the initial development of follicles?

Answer 11

A: Initial follicle development requires no hormonal input.

Question 12

Q: Which hormones are essential for further follicle development and the formation of the antrum?

Answer 12

A: Further follicle development and antrum formation require estrogen, FSH (Follicle Stimulating Hormone), and LH (Luteinizing Hormone).

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Question 13

Q: What are the phases of follicle development dependent on?

Answer 13

A:
- Gonadotropin-Independent Phase: Intraovarian regulations (Primordial to Secondary Follicle).
- Gonadotropin-Responsive Phase: Acquisition of FSH-dependence (Preantral to Early Antral Follicle).
- Gonadotropin-Dependent Phase: FSH-dependence to LH-dependence (Antral Follicle to Corpus Luteum).

Question 14

Q: What role do thecal cells play in follicle development?

Answer 14

A: Thecal cells in the ovarian follicle are stimulated by LH to convert cholesterol into androgen.

Question 15

How does LH influence the thecal cells?

Answer 15

A: LH stimulates the thecal cells to convert cholesterol into androgen.

Question 16

Q: What happens to the androgens produced by thecal cells?

Answer 16

A: The androgens diffuse into the adjacent granulosa cells.

Question 17

Q: What is the role of granulosa cells in follicle development?

Answer 17

A: Granulosa cells, stimulated by FSH, convert androgens into estrogen.

Question 18

Q: How does FSH influence granulosa cells?

Answer 18

A: FSH stimulates the granulosa cells to convert androgens into estrogen.

Question 19

Q: What happens to the estrogen produced by granulosa cells?

Answer 19

A: Estrogen is either secreted into the blood, exerting systemic effects, or remains in the follicle to contribute to antral formation and stimulate the proliferation of granulosa cells.

Question 20

Q: What is the primary role of estrogen in follicle development?

Answer 20

A: Estrogen helps in the proliferation of granulosa cells and contributes to the formation of the antrum within the follicle.

Question 21

Q: What are the two main pathways for estrogen after it is produced by granulosa cells?

Answer 21

A:

Part of the estrogen is secreted into the blood, where it exerts systemic effects.
Part of the estrogen remains within the follicle, contributing to antral formation.

Question 22

Q: What is the significance of the antrum in the ovarian follicle?

Answer 22

A: The antrum is a fluid-filled cavity that forms within the follicle, contributing to its growth and development.

Question 23

Q: What triggers the release of GnRH from the hypothalamus?

Answer 23

A: GnRH release is regulated by hormonal feedback mechanisms involving estrogen and other hormones.

Question 24

Q: How do FSH and LH affect follicle development in the early phase?

Answer 24

A: FSH and LH stimulate the development of follicles by acting on granulosa and thecal cells, respectively.

Question 25

Q: What is the role of granulosa cells during early follicle development?

Answer 25

A: Granulosa cells convert androgens (produced by thecal cells) into estrogen under the influence of FSH.

Question 26

Q: What happens to estrogen levels during the early phase of follicle development?

Answer 26

A: Estrogen levels gradually increase as granulosa cells produce more estrogen.

Question 27

Q: How do lower levels of estrogen influence FSH and LH production?

Answer 27

A: Lower levels of estrogen provide negative feedback to the hypothalamus and pituitary gland, reducing FSH and LH production.

Question 28

Q: What role does AMH play in follicle development?

Answer 28

A: Anti-Müllerian hormone (AMH) produced by granulosa cells helps regulate the recruitment of new follicles and inhibits excessive follicle growth.

Question 29

Q: What effect does FSH have on granulosa cells in the early follicular phase?

Answer 29

A: FSH stimulates granulosa cells to proliferate and produce estrogen.

Question 30

Q: What is the function of thecal cells in early follicle development?

Answer 30

A: Thecal cells, stimulated by LH, produce androgens that are converted to estrogen by granulosa cells.

Question 31

Q: How does the hypothalamic-pituitary-gonadal axis work in early follicle development?

Answer 31

A: GnRH from the hypothalamus stimulates the pituitary gland to release FSH and LH, which act on the ovaries to promote follicle development.

Question 32

Q: What is the feedback mechanism involved in the early follicular phase?

Answer 32

A: Estrogen produced by granulosa cells negatively feedbacks to the hypothalamus and pituitary gland to regulate the levels of GnRH, FSH, and LH.

Question 33

Q: Describe the process of follicle development and dominance during the menstrual cycle.

Answer 33

A:

Follicle development begins with the recruitment of about 6-12 follicles per cycle.
Initially, this process is gonadotropin influenced, with FSH (follicle-stimulating hormone) playing a critical role.
Follicles grow from less than 4mm to about 7-9mm in diameter, at which point the FSH-LH (luteinizing hormone) transition occurs.
The dominant follicle is selected at this transition, influenced by a wave of FSH.
The dominant follicle continues to grow, reaching about 15mm in diameter, and is then ovulated.
Non-dominant follicles undergo atresia, or degeneration.

Question 34

Q: What hormonal changes occur during the follicular phase of the menstrual cycle?

Answer 34

A:

The follicular phase involves the maturation of the primary follicle and is an essential step prior to ovulation.
It requires no initial hormonal input for the first stages but later requires estrogen, FSH, and LH for further development.
During the early follicular phase, estrogen levels are low, which negatively feedbacks to reduce FSH and LH production via the hypothalamic-pituitary axis.
As the dominant follicle is selected, estrogen levels increase, preparing the reproductive tract for possible fertilization.

Question 35

Q: Explain the roles of FSH and LH in follicle development and ovulation.

Answer 35

A:

FSH stimulates the recruitment and initial growth of ovarian follicles.
At the FSH-LH transition, a dominant follicle is selected, which grows faster than others.
LH stimulates the thecal cells in the ovarian follicle, converting cholesterol into androgens.
These androgens diffuse into the granulosa cells, where FSH stimulates their conversion into estrogen.
Estrogen promotes further follicle development and the proliferation of granulosa cells.
Elevated levels of estrogen lead to a surge in LH, which triggers ovulation and the formation of the corpus luteum.

Question 36

Q: How do estrogen and inhibin regulate the levels of FSH and LH during the menstrual cycle?

Answer 36

A:

During the early stages of follicle development, low levels of estrogen provide negative feedback to the hypothalamus and anterior pituitary, reducing the production of FSH and LH.
As the dominant follicle matures and estrogen levels rise, this negative feedback becomes positive, leading to a surge in LH (and to a lesser extent FSH).
Inhibin, produced by the granulosa cells, specifically inhibits FSH production, ensuring that only the dominant follicle continues to develop.

Question 37

Q: Explain the hormonal control of follicle development during the early and late phases of the menstrual cycle.

Answer 37

A:

Early Follicular Phase:

Initial Follicle Development: No hormonal input is required initially.
Further Follicle Development: Estrogen, FSH (follicle-stimulating hormone), and LH (luteinizing hormone) are required for further development.
Hormonal Regulation: Low levels of estrogen negatively feedback to reduce FSH and LH production via the hypothalamic-pituitary axis.
Late Follicular Phase:

Positive Feedback Mechanism: Higher estrogen levels from granulosa cells switch to positive feedback on FSH and LH production.
GnRH Surge: This causes a pre-ovulatory surge of GnRH (gonadotropin-releasing hormone) from the hypothalamus, further increasing pituitary responsiveness to GnRH.
LH Surge: Leads to a significant surge in LH, essential for ovulation.
FSH Surge: Although FSH also surges, it is suppressed by inhibin produced by the granulosa cells of the dominant follicle.

Question 38

Q: Describe the roles of estrogen, FSH, and LH in follicle development and ovulation.

Answer 38

A:

Estrogen:
Produced by granulosa cells, estrogen helps in the proliferation of these cells and promotes further follicle development.
In the early phase, low estrogen levels negatively feedback to the hypothalamus and pituitary.
In the late phase, high estrogen levels switch to positive feedback, enhancing the GnRH surge and leading to the LH surge.
FSH:
Stimulates the initial growth of ovarian follicles.
Required for further follicle development and the conversion of androgens to estrogen in granulosa cells.
Suppressed by inhibin during the late follicular phase to prevent overstimulation.
LH:
Stimulates thecal cells to produce androgens, which granulosa cells convert to estrogen.
The LH surge is crucial for ovulation, triggering the release of the mature ovum.

Question 39

Q: How do inhibin and progesterone regulate FSH and LH during the menstrual cycle?

Answer 39

A:

Inhibin:
Produced by granulosa cells, it specifically inhibits FSH production, ensuring that only the dominant follicle continues to develop.
This suppression of FSH helps to prevent the maturation of multiple follicles.
Progesterone:
Produced after ovulation by the corpus luteum, it helps prepare the reproductive tract for potential pregnancy.
Rising progesterone levels, along with high estrogen levels, enhance the pituitary’s responsiveness to GnRH, leading to the LH surge.

Question 40

Q: Describe the hormonal control of ovulation and the role of LH.

Answer 40

A:

LH Surge:
Triggers Ovulation: An abrupt and massive increase in LH (luteinizing hormone) secretion triggers ovulation.
Stops Estrogen Synthesis: LH stops estrogen synthesis by the follicular cells.
Restarts Meiosis: It restarts meiosis in the oocyte of the developing follicle.
Luteinization: LH causes the differentiation of follicular cells into luteal cells, which produce progesterone.
Ends Follicular Phase: The burst of LH ends the follicular phase and initiates the luteal phase.

Question 41

Q: Explain the phases of follicle development and the hormonal control involved.

Answer 41

A:

Follicular Phase:

Maturation of Primary Follicle: Essential step prior to ovulation.
6-10 Follicles Per Cycle: The fastest growing follicle becomes dominant while others degenerate.
Hormonal Input: Initial development requires no hormonal input. Further development requires estrogen, FSH (follicle-stimulating hormone), and LH.
Negative Feedback: Low levels of estrogen negatively feedback to reduce FSH and LH production.
Positive Feedback Transition: Higher estrogen levels switch to positive feedback, enhancing the GnRH (gonadotropin-releasing hormone) surge.
Luteal Phase:

Ovulation: Triggered by the LH surge.
Formation of Corpus Luteum: Post-ovulation, the follicular cells transform into luteal cells, producing progesterone.

Question 42

Q: How do FSH and LH levels regulate the menstrual cycle phases?

Answer 42

A:

Early Follicular Phase:

Low Estrogen: Negatively feedbacks to reduce FSH and LH.
FSH: Stimulates initial follicle growth and conversion of androgens to estrogen.
Late Follicular Phase:

High Estrogen: Positive feedback increases GnRH and LH production.
LH Surge: Causes ovulation and luteinization of follicular cells.
Luteal Phase:

Progesterone Production: Corpus luteum produces progesterone, which maintains the endometrium for potential pregnancy.
FSH Suppression: Inhibin produced by the dominant follicle suppresses further FSH production.

Question 43

Q: Describe the hormonal changes that trigger ovulation.

Answer 43

A:

LH Surge: A massive increase in LH (luteinizing hormone) secretion triggers ovulation and luteinization of the ruptured follicle.
Stops Estrogen Synthesis: The LH surge stops estrogen synthesis by the follicular cells.
Restarts Meiosis: Meiosis is restarted in the oocyte of the developing follicle.
Luteal Cell Differentiation: LH causes the differentiation of follicular cells into luteal cells that produce progesterone.
Ends Follicular Phase: The burst of LH ends the follicular phase and initiates the luteal phase.

Question 44

Q: What are the key characteristics and hormonal controls of the follicular phase?

Answer 44

A:

Maturation of Primary Follicle: Essential step prior to ovulation.
Follicle Selection: 6-10 follicles develop per cycle, with the fastest-growing follicle becoming dominant and others degenerating.
Initial Development: No hormonal input required initially; further development requires estrogen, FSH (follicle-stimulating hormone), and LH.
Negative Feedback: Low levels of estrogen negatively feedback to reduce FSH and LH production.
Positive Feedback Transition: High estrogen levels switch to positive feedback, enhancing the GnRH (gonadotropin-releasing hormone) surge.

Question 45

Q: What happens during the early luteal phase?

Answer 45

A:

Corpus Luteum Formation:
Follicle Remnant Changes: The ruptured follicle undergoes rapid changes; granulosa and thecal cells collapse into the antrum.
Cell Enlargement: Cells enlarge and convert into steroid-producing tissue, storing cholesterol.
Hormone Secretion: Corpus luteum secretes abundant quantities of progesterone and some estrogen.
Uterus Preparation: Progesterone prepares the uterus for potential implantation.

Question 46

Q: Explain the hormonal control mechanisms involved in follicle development.

Answer 46

A:

Initial Follicle Development: No hormonal input required.
Further Development: Requires estrogen, FSH, and LH.
Negative Feedback: Low estrogen levels reduce FSH and LH production.
Positive Feedback: High estrogen levels increase FSH and LH production.
GnRH Surge: High estrogen and progesterone levels enhance pituitary responsiveness to GnRH, leading to LH and FSH surges.

Question 47

Q: What changes occur during the early luteal phase if fertilization occurs?

Answer 47

A:

Corpus Luteum Functionality:
Continued Growth: The corpus luteum remains functional after ovulation, increasing in size.
Hormone Production: It continues to produce hormones (progesterone and estrogen) to support fertilization.
Inhibits FSH/LH: These hormones block further FSH (follicle-stimulating hormone) and LH (luteinizing hormone) production to prevent new follicle development.

Question 48

Q: What changes occur during the early luteal phase if the ovum is not fertilized?

Answer 48

A:

Corpus Luteum Degeneration:
Stops Hormone Production: The corpus luteum stops producing hormones about 14 days post-ovulation.
Cell Degeneration: Luteal cells degenerate and are phagocytized.
Vascular Supply Withdrawn: Blood supply to the corpus luteum is reduced.
Formation of Corpus Albicans: The tissue is replaced with fibrous tissue, forming the corpus albicans.
Completion of Luteal Phase: The luteal phase is completed once the ovarian cycle is completed.

Question 49

Q: What hormonal changes trigger the pre-ovulatory phase?

Answer 49

A:

Higher Estrogen Levels: Granulosa cells produce higher levels of estrogen.
Positive Feedback: This leads to positive feedback on FSH and LH production.
GnRH Surge: Increased estrogen and progesterone levels enhance pituitary responsiveness to GnRH, causing an LH surge.
FSH Surge: FSH also surges but is suppressed by inhibin produced by granulosa cells of the dominant follicle.

Question 50

Q: What happens during the LH surge?

Answer 50

A:

Stops Estrogen Synthesis: LH surge stops estrogen synthesis by the follicular cells.
Restarts Meiosis: Meiosis is restarted in the oocyte of the developing follicle.
Differentiation of Luteal Cells: LH causes differentiation of follicular cells into luteal cells to produce progesterone.
Ends Follicular Phase: Burst of LH ends the follicular phase and initiates the luteal phase

Question 51

Q: What are the two main layers of the uterus and their functions?

Answer 51

:

Myometrium:

Location: Outer smooth muscle layer.
Function: Provides muscular contractions for childbirth and menstrual flow.
Endometrium:

Location: Inner lining containing blood vessels and glands.
Function:
Estrogen Stimulation: Estrogen stimulates growth of both the myometrium and endometrium.
Progesterone Function:
Nutrient-rich Lining: Converts the endometrium into a hospitable, nutritious lining suitable for implantation.
Reduced Contractility: Reduces the contractility of the uterus to create a quiet environment for implantation and embryonic growth.

Question 52

Q: What hormonal fluctuations occur in the uterus and what are their effects?

Answer 52

A:

Estrogen:
Growth Stimulation: Stimulates the growth of the myometrium and endometrium layers.
Progesterone:
Lining Preparation: Converts the endometrium into a lining suitable for implantation.
Contractility Reduction: Reduces the contractility of the uterus to facilitate a quiet environment for embryo growth

Question 53

Q: How do hormonal fluctuations result in the menstrual or uterine cycle?

Answer 53

A:

Hormonal fluctuations between estrogen and progesterone levels regulate the cyclical changes in the uterus, leading to the menstrual or uterine cycle.

Question 54

Q: How is the menstrual cycle linked to the ovarian cycle?

Answer 54

A:

The menstrual cycle follows the ovarian cycle, typically lasting about 28 days (with considerable variation).
Cyclical changes in the uterus result in menstrual bleeding, which occurs once a month.
If implantation does not occur, the uterus sheds its lining and repairs and rebuilds for the next cycle.

Question 55

Q: What are the three phases of the menstrual cycle?

Answer 55

A:

Menstrual Phase:
The uterus sheds its lining, resulting in menstrual bleeding.
Proliferative Phase:
The uterine lining (endometrium) rebuilds and thickens under the influence of estrogen.
Secretory Phase:
After ovulation, progesterone from the corpus luteum prepares the endometrium for potential implantation of a fertilized ovum.

Question 56

Q: What hormonal changes occur during the menstrual cycle?

Answer 56

A:

Gonadotropin Levels:
FSH (Follicle Stimulating Hormone): Stimulates growth of ovarian follicles.
LH (Luteinizing Hormone): Surge triggers ovulation and formation of the corpus luteum.
Ovarian Hormone Levels:
Estrogen: Peaks during the proliferative phase, stimulating growth of the endometrium.
Progesterone: Rises during the secretory phase, preparing the endometrium for implantation.
Inhibin: Suppresses FSH production to regulate follicle development.
Uterine Cycle
Q: How does the uterine cycle correlate with the ovarian cycle?
A:

Menses: Occurs when the endometrial lining is shed (menstrual phase).
Proliferative Phase: The endometrium rebuilds under the influence of estrogen.
Secretory Phase: The endometrium is further prepared for implantation under the influence of progesterone

Question 57

Q: How is the menstrual cycle linked to the ovarian cycle?

Answer 57

A:

The menstrual cycle follows the ovarian cycle, typically lasting about 28 days (with considerable variation).
Cyclical changes in the uterus result in menstrual bleeding, which occurs once a month.
If implantation does not occur, the uterus sheds its lining and repairs and rebuilds for the next cycle.

Question 58

Q: What are the three phases of the menstrual cycle?

Answer 58

A:

Menstrual Phase:
The uterus sheds its lining, resulting in menstrual bleeding.
Proliferative Phase:
The uterine lining (endometrium) rebuilds and thickens under the influence of estrogen.
Secretory Phase:
After ovulation, progesterone from the corpus luteum prepares the endometrium for potential implantation of a fertilized ovum.

Question 59

Q: What hormonal changes occur during the menstrual cycle?

Answer 59

A:

Gonadotropin Levels:
FSH (Follicle Stimulating Hormone): Stimulates growth of ovarian follicles.
LH (Luteinizing Hormone): Surge triggers ovulation and formation of the corpus luteum.
Ovarian Hormone Levels:
Estrogen: Peaks during the proliferative phase, stimulating growth of the endometrium.
Progesterone: Rises during the secretory phase, preparing the endometrium for implantation.
Inhibin: Suppresses FSH production to regulate follicle development.

Question 60

Q: How does the uterine cycle correlate with the ovarian cycle?

Answer 60

:

Menses: Occurs when the endometrial lining is shed (menstrual phase).
Proliferative Phase: The endometrium rebuilds under the influence of estrogen.
Secretory Phase: The endometrium is further prepared for implantation under the influence of progesterone.

Question 61

Q: What happens during the menstrual phase?

Answer 61

:

Reduction in estrogen and progesterone removes support of the endometrium.
Discharge of blood and endometrial debris occurs (50-150 ml).
Constriction of endometrial vessels disrupts the blood supply and O₂ delivery, flushing endometrium into the uterine lumen.
Contractions of the myometrium expel debris.
Excessive contractions can lead to dysmenorrhea (muscle cramps).

Question 62

Q: What are the key events in the follicular phase?

Answer 62

A:

Maturation of the primary follicle.
Essential step prior to ovulation.
6-10 follicles per cycle, with the fastest-growing follicle becoming dominant while others degenerate.

Question 63

Q: What triggers ovulation?

Answer 63

A:

A surge in LH triggers ovulation.
Stops estrogen synthesis by follicular cells.
Restarts meiosis in the oocyte of the developing follicle.
Causes differentiation of follicular cells into luteal cells, producing progesterone.
Burst of LH ends the follicular phase and initiates the luteal phas

Question 64

Q: What happens during the luteal phase?

Answer 64

:

Early Luteal Phase:
The ruptured follicle transforms into the corpus luteum.
Corpus luteum secretes large amounts of progesterone and some estrogen.
Progesterone prepares the uterus for implantation.
Late Luteal Phase:
If fertilization occurs, the corpus luteum remains functional and continues hormone production.
If fertilization does not occur, the corpus luteum degenerates, vascular supply is withdrawn, and the tissue is replaced with fibrous tissue (corpus albicans).
The luteal phase is completed, and the ovarian cycle restarts.

Question 65

Q: How do hormones control follicle development?

Answer 65

A:

Early Development:
No hormonal input required initially.
FSH stimulates further follicle development and antrum formation.
Late Development:
Higher estrogen levels switch feedback to positive, increasing FSH and LH production.
LH surge leads to ovulation.
Inhibin suppresses FSH to prevent the maturation of additional follicles.

Question 66

Q: How are the menstrual cycle and ovarian cycle connected?

Answer 66

A:

The menstrual cycle mirrors the ovarian cycle, typically lasting about 28 days.
Hormonal changes drive cyclical changes in the uterus, leading to menstrual bleeding if implantation does not occur.

Question 67

Q: What are the phases of the menstrual cycle?

Answer 67

A:

Menstrual Phase:

The endometrial lining is shed, resulting in menstrual bleeding.
Reduction in estrogen and progesterone removes support of the endometrium.
Constriction of endometrial vessels and contractions of the myometrium expel debris.
Proliferative Phase:

Increase in estrogen production by granulosa/thecal cells of follicles.
Stimulates regeneration of the functional layer of the endometrium.
Increases the number of progesterone receptors in the endometrium.
Increases contractility of the myometrium and stimulates glands to produce thin mucus secretion aiding sperm entry.
Secretory Phase:

Progesterone from the corpus luteum prepares the endometrium for potential implantation.
Endometrial glands secrete nutrients to sustain a potential embryo.

Question 68

Q: What hormonal changes occur during the menstrual cycle?

Answer 68

A:

Gonadotropin Levels:
FSH: Stimulates growth of ovarian follicles.
LH: Surge triggers ovulation and formation of the corpus luteum.
Ovarian Hormone Levels:
Estrogen: Peaks during the proliferative phase, stimulating growth of the endometrium.
Progesterone: Rises during the secretory phase, preparing the endometrium for implantation.
Inhibin: Suppresses FSH production to regulate follicle development

Question 69

Q: What are the phases of the ovarian cycle?

Answer 69

:

Follicular Phase:
FSH stimulates the growth of follicles in the ovaries.
Dominant follicle matures and prepares for ovulation.
Ovulation:
Triggered by a surge in LH, releasing the mature egg from the ovary.
Luteal Phase:
Formation of the corpus luteum from the ruptured follicle.
Corpus luteum secretes progesterone and some estrogen to prepare the uterus for implantation.
If no fertilization occurs, the corpus luteum degenerates.

Question 70

Q: What happens during the menstrual phase?

Answer 70

A:

Reduction in estrogen and progesterone removes support of the endometrium.
Discharge of blood and endometrial debris occurs.
Constriction of endometrial vessels disrupts blood supply and O₂ delivery, leading to the shedding of the endometrial lining.
Myometrial contractions expel debris.

Question 71

Q: What happens during the proliferative phase?

Answer 71

A:

Estrogen from the growing follicles stimulates the regeneration of the functional layer of the endometrium.
Increases the number of progesterone receptors in the endometrium.
Increases contractility of the myometrium.
Stimulates glands to produce thin mucus secretion to aid sperm entry

Question 72

Q: What is oogenesis and how does it occur?

Answer 72

A:

Oogenesis is the process of ovum (egg) formation.
Begins with the formation of primary oocytes during fetal development.
Each menstrual cycle, one primary oocyte matures and is ovulated.
Meiosis is completed if fertilization occurs, resulting in a mature ovum

Question 73

Q: How are the menstrual cycle and ovarian cycle connected?

Answer 73

A:

The menstrual cycle mirrors the ovarian cycle, typically lasting about 28 days.
Hormonal changes drive cyclical changes in the uterus, leading to menstrual bleeding if implantation does not occur.

Question 74

Q: What are the phases of the menstrual cycle?

Answer 74

A:

Menstrual Phase:

The endometrial lining is shed, resulting in menstrual bleeding.
Reduction in estrogen and progesterone removes support of the endometrium.
Constriction of endometrial vessels disrupts blood supply and O₂ delivery, leading to the shedding of the endometrial lining.
Myometrial contractions expel debris.
Key Events: Discharge of blood and endometrial debris (50-150 ml), leading to menstruation.
Proliferative Phase:

Estrogen from the growing follicles stimulates the regeneration of the functional layer of the endometrium.
Increases the number of progesterone receptors in the endometrium.
Increases contractility of the myometrium.
Stimulates glands to produce thin mucus secretion to aid sperm entry.
Key Events: Regeneration of the endometrium and preparation for potential fertilization.
Secretory Phase:

Progesterone from the corpus luteum prepares the endometrium for potential implantation.
Endometrial glands secrete nutrients to sustain a potential embryo.
Inhibin produced by granulosa cells suppresses FSH production.
Key Events: Development of the endometrial gland, secretion of glycogen-rich substances, and reduced contractility of the myometrium.

Question 75

Q: What are the phases of the ovarian cycle?

Answer 75

A:

Follicular Phase:

FSH stimulates the growth of follicles in the ovaries.
Dominant follicle matures and prepares for ovulation.
Key Events: Maturation of the primary follicle, selection of the dominant follicle.
Ovulation:

Triggered by a surge in LH, releasing the mature egg from the ovary.
Key Events: LH surge, release of the ovum.
Luteal Phase:

Formation of the corpus luteum from the ruptured follicle.
Corpus luteum secretes progesterone and some estrogen to prepare the uterus for implantation.
If no fertilization occurs, the corpus luteum degenerates.
Key Events: Formation of corpus luteum, secretion of progesterone, degeneration of the corpus luteum if no fertilization occurs

Question 76

Q: What hormonal changes occur during the menstrual cycle?

Answer 76

A:

Gonadotropin Levels:
FSH: Stimulates growth of ovarian follicles.
LH: Surge triggers ovulation and formation of the corpus luteum.
Ovarian Hormone Levels:
Estrogen: Peaks during the proliferative phase, stimulating growth of the endometrium.
Progesterone: Rises during the secretory phase, preparing the endometrium for implantation.
Inhibin: Suppresses FSH production to regulate follicle development.

Question 77

Q: What is oogenesis and how does it occur?

Answer 77

A:

Oogenesis is the process of ovum (egg) formation.
Begins with the formation of primary oocytes during fetal development.
Each menstrual cycle, one primary oocyte matures and is ovulated.
Meiosis is completed if fertilization occurs, resulting in a mature ovum.