Podcast
Questions and Answers
What is the name of the stage in which a primary oocyte remains arrested until puberty?
What is the name of the stage in which a primary oocyte remains arrested until puberty?
- Diplotene (correct)
- Prophase I
- Prophase II
- Metaphase I
The zona pellucida is a structure that surrounds the primary oocyte.
The zona pellucida is a structure that surrounds the primary oocyte.
False (B)
What is the name of the protein complex that holds sister chromatids together?
What is the name of the protein complex that holds sister chromatids together?
cohesin
The ______ is a mature ovarian follicle that releases an egg during ovulation.
The ______ is a mature ovarian follicle that releases an egg during ovulation.
Match the following structures with their correct descriptions:
Match the following structures with their correct descriptions:
Which of the following hormones is primarily responsible for stimulating estrogen production in the ovaries?
Which of the following hormones is primarily responsible for stimulating estrogen production in the ovaries?
The cumulus oophorus is a structure that is present only after ovulation.
The cumulus oophorus is a structure that is present only after ovulation.
What is the role of cortical granules in fertilization?
What is the role of cortical granules in fertilization?
Which hormone plays a significant role in the transition of a ruptured follicle into a corpus luteum?
Which hormone plays a significant role in the transition of a ruptured follicle into a corpus luteum?
The theca externa is the inner layer of the theca folliculi, characterized by its highly vascularized and glandular nature.
The theca externa is the inner layer of the theca folliculi, characterized by its highly vascularized and glandular nature.
What is the primary function of the corpus luteum?
What is the primary function of the corpus luteum?
The hormone ______ stimulates granulosa cell proliferation.
The hormone ______ stimulates granulosa cell proliferation.
Match the following hormones with their primary functions in the female reproductive system:
Match the following hormones with their primary functions in the female reproductive system:
Which of the following processes is NOT directly involved in the regulation of meiotic arrest and resumption in oocytes?
Which of the following processes is NOT directly involved in the regulation of meiotic arrest and resumption in oocytes?
Inhibin is a hormone secreted by the granulosa cells of dominant secondary follicles, and it inhibits the secretion of both FSH and LH.
Inhibin is a hormone secreted by the granulosa cells of dominant secondary follicles, and it inhibits the secretion of both FSH and LH.
What is the primary role of MPF (Maturation Promoting Factor) during oocyte development?
What is the primary role of MPF (Maturation Promoting Factor) during oocyte development?
The ______ phase of the menstrual cycle is characterized by the thickening of the uterine lining due to the influence of progesterone.
The ______ phase of the menstrual cycle is characterized by the thickening of the uterine lining due to the influence of progesterone.
Which phase of oocytogenesis is marked by the completion of meiosis I, resulting in the formation of a secondary oocyte?
Which phase of oocytogenesis is marked by the completion of meiosis I, resulting in the formation of a secondary oocyte?
Flashcards
Theca folliculi
Theca folliculi
Cellular coverings around a developing follicle, forming two layers.
Theca interna
Theca interna
The inner layer of the theca folliculi, highly vascularized and glandular.
Theca externa
Theca externa
The outer layer of the theca folliculi, resembling connective tissue.
Corpus luteum
Corpus luteum
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Progesterone
Progesterone
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MPF (Maturation promoting factor)
MPF (Maturation promoting factor)
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Inhibin
Inhibin
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Menstrual cycle phases
Menstrual cycle phases
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Oocytogenesis
Oocytogenesis
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Ootidogenesis
Ootidogenesis
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Oogonia
Oogonia
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Primary Oocyte
Primary Oocyte
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Secondary Oocyte
Secondary Oocyte
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Cortical Granule
Cortical Granule
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Zona Pellucida
Zona Pellucida
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Graafian Follicle
Graafian Follicle
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FSH (Follicle Stimulating Hormone)
FSH (Follicle Stimulating Hormone)
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LH (Luteinizing Hormone)
LH (Luteinizing Hormone)
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Study Notes
Oogenesis
- Female gamete production: PGC → oogonia → oocytes
- Male gamete production: PGC → spermatogonia → spermatozoa
- Oogonia → primary oocytes (46, 4N)
- Primary oocytes remain dormant in prophase I (diplotene) until puberty
- Primary oocyte develops into a secondary oocyte
- Secondary oocyte (23, 2N) arrests in metaphase II until fertilization
- Mature oocyte (23, N)
- Oocyte diplotene: Primary oocyte arrested in meiosis I, at diplotene stage of prophase I
- Prophase I: Increases genetic variation and reduces chromosome number in daughter cells via meiotic process
- Cortical granule: Vesicle in oocyte cytoplasm releasing enzymes to prevent polyspermy during fertilization
- Condensins: Protein complexes crucial for chromosome condensation in mitosis and meiosis
- Cohesin: Protein complex holding sister chromatids together
- Primordial follicle (one cell thick; squamous): Surrounds arrested primary oocyte; GnRH stimulates FSH release, triggering follicle development
- Zona pellucida: Surrounds secondary oocyte and polar body; binds sperm, species-specific barrier
- Primary follicle (one cell thick; cuboidal): Complete follicular cell layer surrounds primary oocytes at birth; zona pellucida formation begins
- Secondary follicle (many cell layers; cuboidal): Oocytes secrete activin, stimulating granulosa cell proliferation and estrogen secretion
- Graafian follicle (mature follicle): Mature ovarian follicle releasing an egg during ovulation
- Corona radiata: Part of cumulus oophorus, closest layer to zona pellucida
- Cumulus oophorus: Surrounds oocyte in follicle; protection and development during fertilization
- MIF (meiotic inhibitory factor): Causes first meiotic arrest (diplotene, prophase I) until puberty
- FSH (follicle-stimulating hormone): Pituitary gonadotropin; acts on granulosa cells, stimulating estrogen production
- LH (luteinizing hormone): Triggers ovulation, stimulates testosterone production
- Theca: Cellular coverings from ovarian stroma surround developing follicle; differentiates into two layers:
- Theca interna: Highly vascularized and glandular
- Theca externa: Connective tissue-like outer capsule
- Corpus luteum: Ruptured, empty follicle (granulosa cells); lutein reaction converts cells to progesterone-producing cells.
- Progesterone: Prepares uterus for pregnancy (thickening uterine lining)
- MPF (Maturation-promoting factor): Key regulator of cell cycle during fertilization and early development; regulates transition from meiosis to mitosis and early blastomere cycle
- Estrogen: Stimulates LH receptor formation on granulosa cells; mainly produced by theca cells (enzyme production).
- Activin: Stimulates granulosa cell proliferation
- Inhibin: Secreted by granulosa cells; inhibits FSH (and LH) release via negative feedback, causing atresia of other follicles
- Meiotic arrest and resumption: Involves second messengers and hormones
- ARREST: Increased cAMP inactivates MPF, meiosis arrested; cGMP inhibits PDE3A.
- RESUMPTION: LH surge, closes gap junctions, decreases cAMP, activates MPF
- Menstrual cycle: Ovarian, endometrial, and hormonal events
- Proliferative phase (Days 5-14): GnRH stimulates FSH/LH; secondary follicles secrete estrogen; LH/FSH surge for ovulation
- Ovulation: Result of LH surge; ruptured follicle transforms to corpus luteum (progesterone secretion)
- Secretory phase (Days 14-28): Progesterone prepares reproductive tract for implantation; inhibin production; endometrium sheds
- Stages of Oogenesis
- Oocytogenesis: Oogonia develop into primary oocytes via mitosis; complete before/shortly after birth
- Ootidogenesis: Primary oocyte develops into secondary oocyte; begins prenatally, stops in diplotene, resumes at puberty (meiosis I completed); first polar body extruded.
- Oogenesis: Haploid secondary oocyte initiates meiosis II, stops at metaphase II until fertilization
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