Lecture 2: Gametogenesis II Flashcards Preview

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Flashcards in Lecture 2: Gametogenesis II Deck (13):
1

In what stage of meiosis are primary oocytes arrested between birth and puberty?

Diplotene stage of Prophase I

2

After puberty, meiosis resumes in some oocytes. During which stage of meiosis is the oocyte again arrested?

Metaphase II

3

Describe follicular structure in the fetal period with respect to oogenesis.

Diploid oogonium, no follicle, 1 chromatid/chromosome

4

Describe follicular structure in the later fetal period through birth with respect to oogenesis.

Diploid primary oocyte, primodrial follicle with a few flattened follicle cells; 2 chromatids/chormosome

5

Describe follicular structure during birth through puberty with respect to oogenesis.

Diplid primary oocyte, primary follicle with single layer of couboidal follicle cells; ZP separates primary oocyte from follicular cells; 2 chormatids/chromosome

6

Describe follicular structrue after puberty with respect to oogenesis.

Diploid primary oocyte, secondary follicle with mutliple layers of follicle cells and antrum formation beginning; 2 chromatids/chromosome.

Contains haploid secondary oocyte and polar body; later follicle becomes tertiary with follicle cells, corona radiata, antrum

7

Describe follicular structure during ovulation with respect to oogenesis

Haploid secondary oocyte with corona radiata, thecal cells and haploid polar body; 2 chromatids/chromosome

8

Describe follicular structure during ovulation with respect to oogenesis

Completion of second meiotic division; fertilized ovum + second polar body; 1 chromatid/chromosome

9

List the components of the mature Graafian follicle from external to internal.

Theca externa, theca interna, membrana granulosa, mural granulosa cells, antrum, cumulus oophorus, zona pellucida, oocyte

10

Explain how LH receptors are formed on granulosa cells

FSH receptors synthesize aromatase in response to FSH, aromatase converts testosterone into estradiol, estradiol stimulates formation of LH receptors

11

What factors lead to meiotic arrest at diplotene stage of meiosis?

High [cAMP] which inactivates MPF (maturation promoting factor); cGMP from follicular cells inactivate phosphodiesterase 3A (maintains high [cAMP])

12

What is the role of LH in ovulation?

Sudden spike in LH activates adenyl cyclase, stimulating progesterone secretion and releasing oocyte/corona radiata

13

What is the fate of the follicle after ovulation occurs?

2nd meiotic division completed, contains fertilized ovum and polar body