Questions and Answers
What is oogenesis?
Oogenesis begins in the female embryo with the production of oogonia from primordial germ cells. The oogonia divide by mitosis to form cells that begin meiosis, but stop the process at prophase I before birth.
What are oogonia?
An immature female reproductive cell that gives rise to primary oocytes by mitosis.
What are oocytes?
Immature eggs.
What is a primary oocyte?
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When does oogenesis begin?
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Does DNA replication occur during oogenesis?
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How long until oogenesis is complete?
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How many mature gametes are produced per starting cell?
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Match polar body and ovum with their descriptions:
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What is the effect of FSH on the process?
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What is the effect of LH on the process?
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What is the name for the process in which mature gametes are released from the gonads?
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What is a secondary oocyte?
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What is the role of the follicle?
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What does FSH do during the menstrual cycle?
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What does LH do during the menstrual cycle?
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What is the role of estrogen during the menstrual cycle?
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What is the role of progesterone after ovulation?
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What is GnRH and its role?
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What inhibits the anterior pituitary gland?
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What is the endometrium?
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Study Notes
Oogenesis and Related Terms
- Oogenesis starts in the female embryo, producing oogonia from primordial germ cells, which divide by mitosis and initiate meiosis, halting at prophase I before birth.
- Oogonia are immature female reproductive cells that develop into primary oocytes.
- Oocytes refer to immature eggs in the process of development.
- Primary oocytes are developmentally arrested cells originating from oogonia, each located within a small follicle cavity with protective cells.
Timing and Completion of Oogenesis
- Oogenesis begins during embryonic development before birth, with all primary oocytes present at birth being the only ones available for the female's life.
- DNA replication in oogenesis occurs at the fetal stage, not before follicle development or ovulation; it resumes post-fertilization.
- Oogenesis is completed following fertilization; however, most of the process occurs between puberty (around age 12) and menopause (ages 45-50).
Gamete Production Details
- Each starting oogonium produces one mature gamete, which is larger and enriched with cytoplasm and organelles.
- Polar bodies are produced alongside the ovum, containing maternal DNA but minimal cytoplasm, while the ovum is a mature egg with ample cytoplasm and organelles.
Hormonal Regulation
- Follicle-stimulating hormone (FSH) promotes follicle growth and maturation in preparation for ovulation.
- Luteinizing hormone (LH) triggers the formation of the corpus luteum to help sustain the endometrium.
- FSH is released steadily during the menstrual flow phase, encouraging follicle maturation and peaking around day 13; it is modulated by estrogen levels from the follicle.
- LH remains low until day 13, when rising estrogen levels trigger a surge that induces ovulation.
Estrogen and Progesterone Dynamics
- Estrogen secretion, stimulated by LH and FSH from the anterior pituitary gland, peaks around day 10 of the proliferative phase.
- After ovulation, estrogen levels decrease temporarily but rise again during the secretory phase when the corpus luteum secretes both estrogen and progesterone.
- Progesterone remains inactive until the corpus luteum forms, then secretes high levels between days 16 and 24, before declining.
GnRH and Pituitary Gland Regulation
- Gonadotropin-releasing hormone (GnRH) is released by the hypothalamus and stimulates the anterior pituitary to produce LH and FSH.
- High levels of estrogen stimulate GnRH release, while low estrogen and progesterone levels inhibit it to prevent further egg maturation as the corpus luteum regulates hormone levels post-ovulation.
Endometrium Functionality
- The endometrium is the inner lining of the uterus that is shed during menstruation and rebuilt in response to estrogen, which stimulates its thickening in preparation for potential implantation.
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Description
This quiz focuses on the reproductive cycle of the human female, highlighting key concepts such as oogenesis and oogonia. Each flashcard provides definitions to enhance your understanding of these biological terms. Prepare yourself for deeper insights into animal physiology with this informative set.