Reproductive System Flashcards

1
Q

What’s the difference between the types of sex steroids testes and ovaries produce

A

Testes secrete mostly androgens and some oestrogens

Ovaries secrete more oestrogen and also secrete progesterone

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2
Q

Which two steroid hormones control spermatogenesis and also oogenesis (formation of egg and sperm)

A

LH and FSH

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3
Q

What’s the difference majorly in spermatogenesis and oogenesis

A

Oogenesis happens cyclically every 4 weeks new egg released

Sperm continuous reproduction

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4
Q

What is connected to the ovaries

A

Fimbriae (end of Fallopian tube)

And the Fallopian tube

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5
Q

Which layer on the uterus is shed during menstruatikn if no fertilised egg present

A

The endometrium

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6
Q

What is the muscle layer of the uterus called (which oxytocin allows contraction of)

A

Myometrium

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7
Q

Which part of meiosis does the oocyte stop at before it develops into secondary and then ovum within the ovaries

A

Prophase I

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8
Q

Explain the structure of the oocytes which later become the ovum in oogenesis

A

They exist as primordial follicles

The oocyte is surrounded by Stroma cells and follicular cells

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9
Q

Why are you born with many more oocytes than acctually later develop into a matured egg released

A

Most oocytes die before puberty or after the first menstruation due to programmed cell death

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10
Q

What is the ovarian cycle and what is it in sync with

A

The maturation of oocytes into the ovum and release of the ovum into Fallopian tube

It is in sync with the uterine cycle/menstrual cycle

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11
Q

What is the phase called which is the development of the primordial follicles

A

The follicular phase

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12
Q

What happens in the pre Antral follicular phase

A

Primordial follicle develops into a primary follicle due to paracrine factors released causing growth into a primary follicle

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13
Q

Which hormone stops all primordial follicles developing into primary follicles

A

Antimullerian hormone produced by primary follicles themselves

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14
Q

Explain the structure of the primary follicle in the pre Antral follicular phase

A

Oocyte becomes surrounded by granulosa cells

And a zona pellucida glycoprotein layer

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15
Q

Why is the zona pellucida of the primary follicle important

A

Because it acts as a sperm binding site for fertilisation

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16
Q

How do cells communicate in the primary follicle

A

Gap junctions

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17
Q

How does a matured pre Antral follicle differ from a primary follicle

A

Thicker layers of granulosa cells

Thecal cells appear

Zona pellucida stays the same

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18
Q

How do granulosa cells form thecal cells

A

Release paracrine factors into the stroma cells and these form thecal cells

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19
Q

What happens in the antral phase of the follicular phase

A

Thecal cells become apparent

Thicker pellucida

Thicker granulosa cells

Fluid filled sac within the granulosa cells appears

20
Q

How does stimulation of growth differ in antral to pre antral folliclular phase

A

No longer dependant on paracrine factors and due to

FSH hormone

21
Q

What does FSH do in the antral late phase of follicular phase

A

Triggers production of LH receptors on granulosa cells

Increases expression of aromatase enzyme which converts androgens into oestrogens in granulosa cells

22
Q

Which hormone produced in the ovaries by thecal cells in high production causes hypothalamus stop releasing more FSH

A

Oestrogen

23
Q

Which cells actually produce the androgens converted to oestrogens in granulosa cells

A

Thecal cells

24
Q

What does decrease in FSH when too much oestrogen is produced from androgen in granulosa cells cause

A

Cell death in most antral follicles causing dominant one to be chosen for release

25
Q

What surrounds the oocyte in the dominant follicle

A

Pellucida glycoprotein layer and corona radiata

26
Q

What does LH response by dominant follicle cause

A

Undergoes meiotic division up to metaphase 2 (forming secondary oocyte and polar body when it develops into ovum)

Also lowers oestrogen in late follicular phase by inhibiting aromatase

27
Q

What does FSH cause pre ovulation cause important for ovum release

A

Causes cytokine production And hydrolytic enzymes released by thecal and granulosa cells

= degrade the ovary wall

28
Q

When does oestrogen decrease

A

When LH and increases

Or when FSH decreases

29
Q

What happens when the ovary wall and follicle ruptures

A

Corona radiata, ovum and the pellucida layer are released and took in via the fimbriae

30
Q

Why is the corona radiata important

A

Capture of egg by the fimbriae

31
Q

What does the ovary form when the ovum is released

A

Corpus luteum

32
Q

When are LH levels increased

A

When oestrogen has increased- it tries to eradicate this by causing thecal cells to produce more androgens

Lowers oestrogen by inhibiting aromatase enzyme

33
Q

What happens in the luteal phase

A

Granulosa cells fill with lipid

They produce progesterone

Oestrogen decreases due to increased LH (stops aromatase)

Then goes back to normal levels

34
Q

What happens to the corpus Leuteum if not pregnant

A

Forms corpus albicans and slowly degrades

35
Q

Why do LH and FSH increase when corpus albicans is produced

A

Because low oestrogen and progesterone due to less sterofenic tissues like granulosa cells can’t produce progesterone or oestrogen from androgens

36
Q

What happens in the luteal phase of pregnant

A

Placenta release human chorionic gonadotropin

Allows corpus luteum to stay intact

37
Q

What is released in high frequencies of gonadotropin RH and low frequencies

A

FSH= high frequency (egg maturation)

LH- low frequency = triggers ovulation

38
Q

Why is there high progesterone and oestrogen originally in the luteal phase

A

Because low LH before surge and also no feedback of oestrogen causes constant production

39
Q

Important functions of FSH

A

Stimulates growth of immature follicles

Upregulates aromatase expression increasing oestrogen levels

Induce expression of LH receptors in granulosa cells in the late follicular cells to allow ovulation

40
Q

Why do antral follicles die at fast rates

A

When oestrogen is produced in high amounts when FSH released this causes FSHbto stop being released and thus stops promoting follicle maturation

41
Q

What is the importance of LH in the late follicular phase

A

The surge is to stop oestrogen production further as it inhibits aromatase

LH also needed to allow oocyte to go under division until metaphase II to form the matured ovum from secondary oocyte and polar body

Low levels of LH allow progesterone secretion from granulosa cells in the luteal phase

LH causes granulosa to secrete hydrolytic enzymes to degrade ovary wall

42
Q

Why is oestrogen important

A

Prepared the reproductive tract for potential fertilisation and pregnancy

43
Q

Why is progesterone important in luteal phase (due to low LH)

A

Promotes uterine secretions to maintain support for fertilised egg if pregnant

44
Q

When is LH high

A

When FSH is present and progesterone is not present

45
Q

Which hormones in granulosa cells in ovaries repress FSH production

A

Inhibin a and B

46
Q

What causes an LH surge pre ovulation

A

High levels of oestrogen increase LH due to low FSH frequency

High levels of oestrogen then inhibited by LH