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Questions and Answers
What triggers the increase in GnRH at the beginning of the ovarian cycle?
What triggers the increase in GnRH at the beginning of the ovarian cycle?
During the follicular phase, which hormone primarily stimulates the development of primary ovarian follicles?
During the follicular phase, which hormone primarily stimulates the development of primary ovarian follicles?
What happens to the majority of primary ovarian follicles during the follicular phase?
What happens to the majority of primary ovarian follicles during the follicular phase?
Which cells are responsible for producing androgens and progesterone in the large preovulatory follicles?
Which cells are responsible for producing androgens and progesterone in the large preovulatory follicles?
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What is the main effect of increased estrogen levels during the follicular phase?
What is the main effect of increased estrogen levels during the follicular phase?
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What is the consequence of the dominant follicle continuing to develop while others regress?
What is the consequence of the dominant follicle continuing to develop while others regress?
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What physiological change occurs during ovulation that is initiated by the LH surge?
What physiological change occurs during ovulation that is initiated by the LH surge?
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At what point in the ovarian cycle does ovulation occur relative to menstruation?
At what point in the ovarian cycle does ovulation occur relative to menstruation?
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What is the role of granulosa cells in the female hormonal system?
What is the role of granulosa cells in the female hormonal system?
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During which phase of the menstrual cycle is ovulation most likely to occur?
During which phase of the menstrual cycle is ovulation most likely to occur?
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What hormones are primarily responsible for the inhibition of LH and FSH release during the menstrual cycle?
What hormones are primarily responsible for the inhibition of LH and FSH release during the menstrual cycle?
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At what age does menarche typically begin in females?
At what age does menarche typically begin in females?
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What primarily triggers the anterior pituitary to release FSH?
What primarily triggers the anterior pituitary to release FSH?
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How many primary ovarian follicles are typically present at puberty?
How many primary ovarian follicles are typically present at puberty?
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What phase of the uterine cycle is characterized by secretory changes?
What phase of the uterine cycle is characterized by secretory changes?
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What hormonal changes occur in the ovaries during the luteal phase?
What hormonal changes occur in the ovaries during the luteal phase?
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Which hormone is primarily responsible for the dominant progestational activity in the female body?
Which hormone is primarily responsible for the dominant progestational activity in the female body?
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What is the main source of estrogen secretion during the first half of the menstrual cycle?
What is the main source of estrogen secretion during the first half of the menstrual cycle?
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What process occurs involving the conversion of androgens to estrogens in granulosa cells?
What process occurs involving the conversion of androgens to estrogens in granulosa cells?
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Which of the following is NOT a function of estrogen?
Which of the following is NOT a function of estrogen?
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How does diminished liver function affect estrogen activity in the body?
How does diminished liver function affect estrogen activity in the body?
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What is the effect of estrogen on bone density during menopause?
What is the effect of estrogen on bone density during menopause?
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Which of these hormones cannot be synthesized from cholesterol?
Which of these hormones cannot be synthesized from cholesterol?
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What condition is increased in women due to the hypercoagulability effect of estrogen?
What condition is increased in women due to the hypercoagulability effect of estrogen?
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What hormonal change occurs immediately before ovulation?
What hormonal change occurs immediately before ovulation?
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What is formed as a result of the ruptured follicle during ovulation?
What is formed as a result of the ruptured follicle during ovulation?
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Which cells are responsible for converting androgens into female hormones during the luteal phase?
Which cells are responsible for converting androgens into female hormones during the luteal phase?
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What initiates the degeneration of the corpus luteum if pregnancy does not occur?
What initiates the degeneration of the corpus luteum if pregnancy does not occur?
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During the proliferative phase of the endometrial cycle, what primarily drives the changes in the endometrium?
During the proliferative phase of the endometrial cycle, what primarily drives the changes in the endometrium?
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What happens to the corpus luteum if pregnancy occurs?
What happens to the corpus luteum if pregnancy occurs?
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What role does the proteolytic enzyme secreted by the thecal cells play during ovulation?
What role does the proteolytic enzyme secreted by the thecal cells play during ovulation?
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Which phase characterizes the ovarian cycle immediately following ovulation?
Which phase characterizes the ovarian cycle immediately following ovulation?
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What triggers the onset of puberty and menarche in females?
What triggers the onset of puberty and menarche in females?
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What physiological change is NOT typically associated with menopause?
What physiological change is NOT typically associated with menopause?
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How long does an ovum remain viable for fertilization after being expelled from the ovary?
How long does an ovum remain viable for fertilization after being expelled from the ovary?
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What is the main factor contributing to the cessation of monthly cycles during menopause?
What is the main factor contributing to the cessation of monthly cycles during menopause?
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During what timeframe must sperm be present for fertilization to occur following ovulation?
During what timeframe must sperm be present for fertilization to occur following ovulation?
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Which of the following symptoms is not a common physiological change due to estrogen loss during menopause?
Which of the following symptoms is not a common physiological change due to estrogen loss during menopause?
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What is the approximate average age for the onset of menarche?
What is the approximate average age for the onset of menarche?
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What is a primary reason for the high failure rate of contraceptive methods that rely on avoiding intercourse near ovulation?
What is a primary reason for the high failure rate of contraceptive methods that rely on avoiding intercourse near ovulation?
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Study Notes
Introduction
- The ovaries are the primary sex organs in females.
- They produce eggs (ova) and secrete estrogen, progesterone, and small amounts of androgens.
- Ovaries contain primordial follicles, which decrease in number with age.
- Granulosa cells secrete estrogen and progesterone, while theca cells produce androgens.
- The female reproductive system is regulated by hormones from the hypothalamus, anterior pituitary, and ovaries.
- The hypothalamus releases gonadotropin-releasing hormone (GnRH), stimulating the anterior pituitary.
- The anterior pituitary secretes follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
- FSH stimulates follicle development, while LH stimulates the formation of the corpus luteum.
- Estrogen and progesterone, particularly estrogen, inhibit LH and FSH release through direct pituitary or indirect hypothalamic effects.
Monthly Hormonal Cycle
- The menstrual cycle involves cyclic events during a woman's reproductive period, encompassing ovulation and endometrial preparation for implantation.
- It begins at puberty (menarche), typically between 12-15 years old, and ceases at menopause, usually between 45-50 years old.
- The cycle lasts approximately 28 days but can range from 20-40 days.
- The menstrual cycle is controlled by the hypothalamus-pituitary axis, involving GnRH from the hypothalamus and FSH & LH from the anterior pituitary.
Phases of the Menstrual Cycle
- The ovarian cycle comprises events occurring in the ovaries, divided into three phases: follicular, ovulation, and luteal phases.
- The uterine cycle, involving changes in the uterus, has three phases: proliferation, secretory changes, and menstruation.
Ovarian Cycle
- The follicular phase (preovulatory) is marked by follicle development under the influence of FSH and LH.
- Follicles enlarge, granulosa cells secrete estrogen, and theca cells produce androgens.
- A dominant follicle emerges, while others undergo atresia and degenerate.
- The ovulation phase involves the rupture of the dominant follicle, releasing the ovum into the fallopian tube.
- The LH surge triggers ovulation, preceded by an estrogen peak.
- The thecal cells secrete progesterone and proteolytic enzymes, dissolving the follicular capsule.
- The ruptured follicle becomes the corpus hemorrhagicum, sometimes causing lower abdominal pain.
- The luteal phase (postovulatory) involves the formation of the corpus luteum, which secretes high levels of progesterone and smaller amounts of estrogen.
Uterine Cycle
- The proliferative phase is driven by estrogen, leading to endometrial growth.
- The secretory phase is governed by progesterone, preparing the endometrium for implantation.
- Menstruation occurs if fertilization doesn't happen, shedding the thickened endometrium.
Ovarian Hormones
- Estrogen is secreted by developing follicles and the corpus luteum.
- Progesterone is primarily produced by the corpus luteum.
- Androgens from theca cells convert to estrogens in granulosa cells by the enzyme aromatase.
- Estrogen and progesterone are transported bound to plasma albumin and specific binding globulins.
- The liver inactivates estrogens by conjugation with glucuronides and sulfates, excreted in bile and urine.
Functions of Estrogen
- Plays a crucial role in the menstrual cycle.
- Stimulates the growth and proliferation of female sex organs and other reproductive tissues.
- Responsible for the development of secondary sexual characteristics in females.
- Influences bone health, stimulating osteoblastic activity but also causing closure of epiphyses.
- Increases total body protein and metabolic rate.
- Contributes to hypercoagulability, increasing the risk of thromboembolism.
Functions of Progesterone
- Key role in the menstrual cycle, influencing the secretory and luteal phases.
- Facilitates the effect of oxytocin on the uterus.
Puberty and Menarche
- Puberty marks the onset of adult sexual life, with menarche signifying the beginning of menstruation.
- Puberty is triggered by a gradual increase in FSH and LH secretion.
- It typically begins around age 8 and culminates in menarche between 11 and 16 years old.
- Before puberty, the ovaries remain inactive.
Menopause
- Menopause marks the cessation of menstrual cycles and a significant decline in ovarian hormone levels.
- Insufficient primary follicles in the ovaries lead to inadequate estrogen production.
- This prevents the LH surge, resulting in ovulation cessation.
- After irregular anovulatory cycles, estrogen production drops to near zero.
- FSH and LH levels rise due to the absence of inhibitory effects.
- Declining estrogen levels cause physiological changes, including hot flushes, psychological symptoms, and decreased bone density.
Female Fertility
- The fertile period occurs around ovulation.
- Sperm can remain viable for up to 5 days in the female reproductive tract.
- Fertilization requires intercourse within a few days before ovulation to a few hours after ovulation.
Method of Contraception
- Avoiding intercourse near ovulation is a contraceptive method with a high failure rate (20-25% annually) due to difficulty in predicting ovulation.
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Description
Explore the essential functions of the ovaries, their role in hormone production, and the regulation of the menstrual cycle. This quiz covers the hormonal interplay and physiological changes occurring in the female reproductive system. Test your understanding of the key concepts related to female reproductive health!
