Lecture 37: FEMALE REPRODUCTIVE SYSTEM 2 Flashcards

1
Q

What is oogenesis?

A

Formation and development of the oocyte from oogonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does oogenesis require?

A

Mitosis and meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is produced before birth?

A

A lifetime supply of gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When does oogenesis occur?

A

It is initiated before birth and continues between puberty and menopause

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is oogenesis described?

A

Cyclic (1 ovulation every 28 days on average)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where do oocytes develop?

A

Within an ovarian follicle (stationary) - 1 oocyte per follicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is in the gonad before birth?

A

oogonium (diploid, 2n=46)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens to the population of oogonia?

A

They increase by mitosis (stops before birth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What do oogonia do?

A

Differentiate to form primary oocytes (diploid, 2n=46)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are primary oocytes encased in?

A

Primordial follicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens with many primary oocytes?

A

They undergo atresia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do primary oocytes start?

A

Meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When does meiosis halt?

A

At prophase 1 until puberty begins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many oocytes do females have at puberty?

A

Approximately 300,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens under GnRH influence?

A

A small number of follicles recruited each ovarian/menstrual cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does only one oocyte do?

A

Complete development and ovulate (within the dominant follicle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the primary oocyte complete?

A

Meiosis 1 to form a secondary oocyte and first polar body (both haploid, n=23)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the secondary oocyte start?

A

Meiosis 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When does meiosis 2 halt?

A

At metaphase 2 which is suspended until fertilisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When does meiosis 2 resume?

A

When the sperm penetrates the plasma membrane of the ovum at fertilisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens if the secondary oocyte is not fertilised?

A

It will degenerate by atresia and therefore never complete meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does one primary oocyte form?

A

1 ova and 3 polar bodies will also form which under go atresia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the layers of the follicles?

A

Granulosa cells inside and theca cells outside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do granules cells produce?

A

Inhibin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens in ovulation?

A

Oocyte and corona radiata released into peritoneal cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the female reproductive hormones?

A

GnRH, FSH, LH, estradiol, inhibit and progesterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where is GnRH released from?

A

The hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What does GnRH do?

A

Stimulate the release of FSH and LH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where is FSH released from?

A

The anterior pituitary

30
Q

What does FSH do?

A

Stimulate growth of ovarian follicles

31
Q

Where is LH released from?

A

Anterior pituitary

32
Q

What does LH do?

A

Surge of LH is involved in ovulation, formation of corpus luteum

33
Q

Where is estradiol released from?

A

Developing follices

34
Q

What does estradiol do?

A

Assists follicle growth (with FSH), bone and muscle growth, endometrial growth, secondary sex characteristics, feedback to anterior pituitary

35
Q

Where is inhibin released from?

A

Granulosa cells

36
Q

What does inhibit do?

A

Negative feedback to anterior pituitary to suppress FSH

37
Q

Where is progesterone released from?

A

The corpus luteum

38
Q

What does progesterone do?

A

Negatively feeds back to suppress GnRH (therefore LH and FSH), endometrial maturation, maintains pregnant state

39
Q

What are the ovarian/menstrual cycles?

A

The regular cyclic changes in the ovary and uterus that prepare an oocyte/ova for fertilisation and the endometrium for embryo implantation

40
Q

When does the menstrual cycle occur?

A

On approximately monthly basis (average 28 days) between menarche and menopause

41
Q

What is menarche?

A

First menstrual period

42
Q

When does menarche occur?

A

At age 12-13 on average

43
Q

What is menarche part of?

A

Puberty - orchestrated by increase in sex steroid production (oestrogen’s) by the gonads

44
Q

What is menopause?

A

Cessation of menstruation

45
Q

When does menopause occur?

A

Typically in early 50’s

46
Q

What is menopause caused by?

A

Reduction of estradiol and progesterone due to absence of or lack of response by follicles. Anterior pituitary negative feedback no longer active therefore FSH/LH high

47
Q

What are the phases of the ovarian cycle?

A

follicular (preovulatory) phase and luteal (postovulatory) phase

48
Q

When does the follicular phase occur?

A

Days 1-14

49
Q

When does the luteal phase occur?

A

Days 15-28

50
Q

What happens in the follicular phase?

A

Increased FSH from the anterior pituitary stimulates follicular growth

51
Q

What do growing follicles secrete?

A

Estradiol and inhibin

52
Q

What does growing follicles secreting estradiol and inhibin cause?

A

reduced FSH from anterior pituitary (negative feedback) and growing follicles undergo atresia (except the dominant follicle)

53
Q

What does the dominant follicle secrete?

A

Large amounts of estradiol

54
Q

What does high estradiol stimulate?

A

Surge of LH (positive feedback)

55
Q

what happens because of the surge of LH?

A

The follicle ruptures and ovulation occurs

56
Q

What happens in ovulation?

A

Oocyte enters peritoneal space/collected into uterine tube

57
Q

What happens in the luteal phase?

A

Ovulated follicle collapses and forms corpus luteum

58
Q

What does the corpus luteum secrete?

A

Progesterone, estradiol and inhibin

59
Q

What do progesterone, estradiol and inhibin do?

A

Decrease FSH and LH secretion - negative feedback on hypothalamus

60
Q

What happens if fertilisation and implantation don’t occur?

A

The corpus luteum involutes (luteolysis) and eventually forms the corpus albicans

61
Q

What happens to hormones if fertilisation doesn’t occur?

A

A fall in progesterone and estradiol which removes negative feedback on FSH and LH so the cycle starts again

62
Q

What are the phases of the menstrual cycle?

A

Menstrual and proliferative, then secretory

63
Q

When do the menstrual and proliferative phases occur?

A

day 1-14

64
Q

When does the secretory phase occur?

A

Day 15-28

65
Q

What happens in the menstrual phase?

A

Endometrium breaks down and bleeds (from spiral arterioles)

66
Q

What happens from approximately days 6-14 of the menstrual and proliferative phase?

A

Estradiol stimulates endometrial growth. Rapid tissue growth, including growth of glands and vasculature

67
Q

What happens after ovulation (day 14)?

A

Corpus luteum secretes progesterone

68
Q

What does progesterone promote?

A

Endometrial maturation

69
Q

What happens in endometrial maturation?

A

Glands become secretory and spiral arterioles grow and coil

70
Q

What happens if fertilisation and implantation do not occur?

A

Corpus luteum atrophies (breaks down), progesterone levels fall, spiral arteries contract, endometrial tissue breaks down and bleeding occurs, shed tissue and blood removed via cervix and vagina (menstruation/menses)