Oo genesis Flashcards

1
Q

What is oogenesis

A

formation of the female gamete

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2
Q

What does oogenesis start from

A

Undifferentiated primordial germ cell

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3
Q

How many copies of chromosomes do primordial germ cells have?

A

2 copies (diploid)

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4
Q

What are diploid cells

A

2 homologs of each chromosome, one from each parent

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5
Q

What must happen prior to fertilization for the diploid cell to be produced

A

number of chromosomes must be reduced, haploid cells must be made

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6
Q

What happens during mitosis

A

two identical cells are produced

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7
Q

What are the 5 stages of prophase 1

A
Leptotene
zygotene
pachytene
diplotene
diakinesis
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8
Q

What happens during Leptotene

A

chromosomes appear as thin threads

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9
Q

What happens during zygotene

A

Condensation of threads

Synapsis directed by the synaptonemal complex

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10
Q

What happens during pachytene

A

genetic rcombination

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11
Q

What hapens during diplotene

A

Homologs start to separate

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12
Q

What happens during diakinesis

A

centromers move away from each other

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13
Q

What happens during metaphase 1

A

homologs align equidistant to each other

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14
Q

What happpens during anaphase 1

A

Homologs are separated

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15
Q

What happens during telophase 1

A

two daughter cells are formed

Each daughter cell contains one copy fo the homologous chromosomes

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16
Q

How do oogoni multiply

17
Q

When is meiosis arrested

A

Late diplotene stage (dictyate)

18
Q

When does meiosis resume

A

until activation of the oocyte in response to ovulatory gonadotropic stimulus

19
Q

What is a primoridal follicle

A

oocyte enclosed by single layer of pregranulosa cells

20
Q

When is the 2nd meiotic division arrested

A

metaphase 2

21
Q

when does the 2nd meiotic division resume

A

fertilization

22
Q

What is folliculogenesis

A

formation of an antral follicle starting from a primordial follicle

23
Q

what is a follicle

A

oocyte surrounded by somatic cells

24
Q

Do primary and secondary follicles need gonadotropins

25
What does development beyond secondary follicles require
gonadotropins
26
What does FSH do
stimulate follicular growth
27
what does LH do
maturation of oocyte | triggers ovulation
28
What is the two cell two gonadotropin hypothesis
LH: Theca cell turns cholesterol to androgen FSH: Granulosa cell, turns androgen into estrogen
29
What is the only positive feedback loop
Estrogen on the hypothalamus/GnRH once it reaches threshold
30
What happens when estrogen reaches threshold
Burst of GnRH Surge of LH follicular maturation and ovulation
31
what does the LH surge do to meiosis
causes it to resume (first polar body extruded)
32
what do the theca cells do after the LH surge
produce low levels of progesterone
33
What happens to progesterone levels during CL formation
slowly increase
34
What is progesterone required for
maintenance of pregnancy
35
What causes the CL to regress in large animals
PGF2alpha
36
What does the CL become after its destruction
corpus albicans