Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 1 > Menstrual cycle > Flashcards

Menstrual cycle Flashcards

1
Q

What is the gonadotropin releasing hormone?

A

Decaprotein which stimulates the production of testosterone in the testes or oestrogen and progesterone in the ovaries.

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

Where is gonadotropin hormone released from?

A

The hypothalamus to act on the gonadotrophin region of the anterior pituitary gland.

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

What is the N-terminal?

A

Free amine group at the start of a protein which is the first to be synthesised by a ribosome.

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

What is the C terminal?

A

End group of a protein which binds to other molecules.

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

Which hormones are glycoproteins?

A

Leutinisng Hormone (LH), Follicular Stimulating Hormone (FSH) and Chronic gonadiotropin. They are dimers with identical alpha chains but distinct beta chains.

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

What is the LH receptor?

A

G protein coupled receptors which respond to LH on granulosa and theca cells.

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

What is the FSH receptor?

A

G protein coupled receptor which FSH binds to and dimerises.

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

What are the classes of steroids?

A

Mineral corticoids, Progestogins, androgestogin, oestrogestogin and glucocortcoids. They are synthesised from cholesterol.

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

How does cholesterol synthesis occur?

A

From acetate unit in the mitochondria. Cholesterol -> progestogin or continue to form -> androgenin. From androgein, it can form estrone or estriol. Androgenin can forms testosterone and forms acetasiation to form oestrogen for females or dihydrotestosterone for males.

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

How do steroids act?

A

They are lipid soluble and pass directly through the membrane to act on the nulceus via sterol responsive binding elements.

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

How are hromones regulated?

A

No of receptors, binding proteins, clearance rate, production rate

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

Comparison of hormone clearance rate?

A

Steroids < Prostaglandin < LH < FSH < Chronic goniatropin

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

What are the consitutents of the anterior pituitary gland?

A

Consists of lactotrophin and gondotrophin. The lactotrophin region produces prolactin and the gonadotrophin region produces the gonadotrophin hormones LH and FSH.

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

What is gametogenic potential?

A

The maximum number of gametes which can be produced. In females, this is achieved as a foeutus where they achieve maximum gamete number at 3/4 months past conception which decreases.

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

How do oocytes form?

A

From a primordial germ cell which undergoes mitosis to form the primary oocyte. It is arrested in the diplotene subphase of prophase II in meiosis where homologous chromosomes are attached to the chiasmata and forms a germinal vesicle. It remains in this phase until puberty with the rise in FSH levels to continue meiosis I and form a secondary oocyte

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

What is diplotene?

A

Substage in prophase II where homologus chromosomes are attached to chiasmata and is prior to chromatin condensation. This is the stage in meiosis where oocytes are arressted in development.

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

What is the germinal vesicle?

A

The nucleus present in an oocyte.

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

What is the pattern of gamete production?

A

Proliferation by mitosis,

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

What is the primordial follicle?

A

Singular oocyte surrounded by layer of granulosa cells arrested in diplotene phase of prophase I. This is formed prior to birth while the female is in utero and cannot progress until puberty where menstruation occurs.

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

What is an antrum?

A

Fluid filled cavity present in a tertiary or mature follicle. It contains blood plasma and secretions from granulosa cells and theca cells.

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

What is folliculogenesis?

A

Formation of a follicle from a
primordial follicle ->primary oocyte with a fully grown oocyte-> secondary preantral follicle -> tertiary antral follicle containing theca cells -> mature follicle.

Primary follicle is the primary oocyte with mesenchymal tissue and layer of granulosa cells.

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

What are the stages of development from an oocyte?

A

Primordial germ cell -> oocyte -> primary follicle -> secondary preantral follicle -> tertiary antral follicle containing theca cells -> mature follicle

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

What is atresia?

A

The death of an oocyte prior to ovulation, due to low levels of LH and FSH

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

What is follicular trickle?

A

Primary follicle -> secondary follicle which can enter atresia. It will only not occur atresia and progresses to a tertiary follicle dependent on levels of LH and FSH in the body

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

What is the difference between a primary and secondary follicle?

A

Secondary follicle is larger and is a pre-antral cell which contains fluid from the blood plasma and the granulosa cells. It also begins to develop theca cells.

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

What is the structure of a mature oocyte?

A

It has an outer layer of theca cells, then granulosa cells and a much larger antrum than teritary follicle. Below antrum is the layer of granulosa cells called the cumulus oophorus and innermost layer is the corona radiata. The granulosa cells are connected to the oocytes via stalk.

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

Where does LH act on?

A

Thecal cells to synthesise androgen.

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

Where does FSH act on?

A

Granulosa cells to produce the aromatase enzyme which converts androgens from theca cells—> oestrogen and inihibin B

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

What are the stages of the ovarian cycle?

A

Follicular phase, luteal phase and ovulation.

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

What is the follicular phase?

A

Gonadotropin hormone is released from the hypothalamus and acts on gonadotrophin region of anterior pituitary gland to produce LH and FSH. LH acts on thecal cells for androgen production. Androgens enter granulosa cells. FSH dimerises when binding to receptors on granulosa cells and causes formation of oestrogen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the negative feedback mechanism on LH?

A

Low-> moderate plasma oestrogen levels produced by the granulosa cells during the follicular phase inhibits release. Progesterone also inhibits LH.

High levels of oestrogen has a positive feedback effect of LH release.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the negative feedback mechanism on FSH?

A

By Inhibin B produced by granulosa cells acting on the pituitary gland.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the negative feedback mechanism on gonadotropin releasing hormone?

A

Low-> moderate oestrogen, oestrogen + progesterone and inhibin B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How does the follicular phase end?

A

High levels of plasma oestrogen and oestrogen production in granulosa cells causes positive feedback to increased release of LH from the pituitary gland.

Granulosa cells now express LH receptors and respond to LH binding by producing progesterone. The follicle undergoes ovulation. Remnant of the follicle is the corpus luteum which produce progesterone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is ovulation?

A

Release of the most mature follicle in the ovary which is triggered by LH surge to form secondary oocyte. The outer layer swells with viscous fluid and forms a stigma which then ruptures and allows the ovum to pass through, leaving behind a luteal structure formed of granulosa and theca cells. This occurs when LH levels are high.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is a stigma?

A

Point on the ovarian surface which ruptures to allow the egg to pass through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What happens to hormone levels in ovulation?

A

Oestrogen falls and progresterone rises and high levels of LH to stimulate egg release.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the corona radiata?

A

Layer of cuboidal granulosa cells which are attached to the zona pellucida of the Egg as it leaves the ovum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the dominant follicle?

A

Follicle which enlarges to release ovum.

39
Q

What is ovulation?

A

Release of ovum after LH surge from dominant follcile.

40
Q

What is a polar body?

A

Cellular byproduct of meiosis where the oocyte has chromosomes stored. First polar body contais homologous chromosomes and second polar body contains haploid chromosomes.

41
Q

How does the oocyte mature during the menstrual cycle?

A

After LH surge, it undergoes nuclear maturation which is reversal of cell cycle arrest. It loses half the first polar body with homologous chromosomes and it is unequal. It undergoes development with most of the cyptoplasm contained to form the secondary oocyte. At ovulation, it continues meiosis and arrests at metaphase II, until fertilisation with a sperm occurs.

42
Q

What is a stigma?

A

Area of ovarian surface where follicle penetrates to be released in ovulation

43
Q

What are thecal cells?

A

Respond to LH to produce
Cholesterol -> progesterone -> androgen. It lacks aromatase enzyme so it diffuses to enter granulosa cells to produce oestrogen.

44
Q

Which hormone is important for folliculogenesis?

A

FSH (Follicle stimulating hormone). This is from action of gonadotrophin releasing hormone on the pituitary gland.

45
Q

What are the luteal cells?

A

Thecal and granulosa cells that respond to LH.

46
Q

Where is inhibin produced?

A

In granulosa cells as a negative feedback mechanism for FSH.

47
Q

What is the luteal phase?

A

After ovulation, the corpus loteum degrades

48
Q

Which hormones are produced in the luteal phase?

A

Progesterone which reaches its peak and inhibits LH production. Oestrogen levels increase.

49
Q

Which hormone triggers ovulation?

A

LH surge

50
Q

What is the uterine cycle?

A

Consists of menstruation, proliferation and secretory phase.

51
Q

What prevents the atresia of secondary follicle?

A

Rising levels of LH via positive feedback from high levels of oestrogen.

52
Q

Why do LH levels drop?

A

Occurs after ovulation due to progesterone production reaching its peak from corpus luteum.

53
Q

When do progesterone levels increase?

A

After ovulation, by a remnant of the follicle called the corpus luteum.

54
Q

What is menstruation?

A

Shedding of the uterine lining.

55
Q

What is the proliferative phase?

A

During follicular phase where the endometrium and myomtrium proliferate after menstruation via the action of oestrogen. Cervical mucosal changes occur as glands grow and spiral arteries begin to emerge.

56
Q

What is the corpus luteum?

A

Temporary organ in the luteal phase which releases androgens and produces progesterone, oestrogen and inhibn A

57
Q

What is the secretory phase?

A

During luteal phase where cervical mucosal changes occur and blood supply to the endometrium changes. Oestrogen and progestorone are produced by the corpus luteum. Oestrogen reduces cell proliferation and progesterone causes swelling, and thickening of the endometrium to prepare for implantation.

58
Q

Where is oestrogen produced?

A

In the ovaries in the form of estradiol, estrone and estriol.

59
Q

Where is progesterone produced?

A

By the corpus luteum.

60
Q

What is the order of activity of oestrogen types?

A

Estradiol > estrone > estriol

61
Q

What are the effects of oestrogen?

A

Prevents memory loss, reduces cholesterol, maintains bone density, increases breast and vagina development and signals start of the menstrual cycle and maintains the uterus for a foetus.

62
Q

What is the combined oral contraceptive?

A

Contains both oestrogen and progesterone. Oestrogen will inhibit LH and progestrone and oestrogen will both inhibit the production of LH from the anterior pituitary gland and gonadotrophin releasing hormone from the hypothalamus.

63
Q

What is the morning after pill?

A

Contains progesterone which prevents ovulation and blocks fertilisation by preventing fertilsied egg from implanting.

64
Q

What is the role of androgens?

A

Converted into oestrogen which regulates menstruation.

65
Q

What are the effect of low to moderate oestrogen?

A

Negative feedback on the menstrual cycle to causes FSH and LH levels to fall.

66
Q

What is the corpus luteum formed of?

A

No egg- formed of the granulosa and theca cells.

67
Q

What are the effects of high oestrogen?

A

Positive feedback on the cycle causes the increase of LH and FSH levels

68
Q

What causes LH and FSH surge in ovulation?

A

High levels of oestrogen.

69
Q

When do progesterone levels rise?

A

Following LH surge, ovulation occurs and causes the formation of the corpus luteum. Corpus luteum will produce progesterone.

70
Q

Which hormone is responsible for the start of the menstrual cycle?

A

Follicular Leutinising Hormone which prevents atresia of the primary follicle to progress past diplotene phase of meios I and form secondary follicle

71
Q

What is the role of LH and when does it decrease?

A

Formation of corpus luteum. It decreases when progesterone rises due to negative feedback

72
Q

Role of progesterone?

A

Maintenace of the lining for the ovulated egg to be fertilised and implanted It increases thickening of cervical bmucus and vascularisation of the endothelium. During luteal phase, it inhibits FSH and LH release.

73
Q

Why do progesterone levels decrease?

A

Egg is not fertilised and after 10 days, progesterone decreases and removes negative feedback and causes menstruation to occur.

74
Q

Endometrium histology

A

Simple columnar epithelia

75
Q

What are the arteries of the stratum functionale?

A

Spiral and coiled arteries. These are lost during menstruation.

76
Q

What are the arteries of the stratum basalis?

A

Straight arteries.

77
Q

What happens in the proliferative phase?

A

Oestrogen levels rise in the midfollicular phase which causes the proliferation of the starco functionale and the angiogenesis of spiral and coiled arteries, There is production of thin runny mucus

78
Q

What happens in the secretory phase?

A

Progesterone levels rise and oestrogen and causes proliferation of starco functionale along with angiogenesis of spiral and coiled arteries and production of thick cervical mucus. Inhibin A produced by granulosa cells in the luteal phase also inhibits FSH and LH.

79
Q

Where is GnRH produced from?

A

Arcuate and supraoptic nucleus of the hypothalamus

80
Q

How does the primordial follicle become a primary follicle?

A

Prior to puberty in utero- Androgen production causes the differentiation by mitosis. Primary follicle has a larger oocyte and a thicker layer of granulosa cells.

81
Q

How does the primary follicle become a seocndary follicle?

A

Levels of FSH and LH rising which saves it from atresia. FSH acts on granulosa cells to cause production of oestrogen.

82
Q

What is the difference between primary and secondary follicle?

A

Secondary follicle is larger, contains pockets of pre-antral fluid formed from granulosa cell and blood plasma production. The oocyte is larger and now surrounded by a zona pellucida.

83
Q

What causes the formation of androgens?

A

LH acts on theca cells to convert cholesterol-> androgens via reductase enzyme.

84
Q

How does oestrogen form?

A

FSH acts on granulosa cells to cause androgens -> oestrogen via aromatase enzyme.

85
Q

What causes formation of the folliciular flid in the secondary follicle? WHat is formed of?

A

FSH- follicular fluid is formed of hyaluronic acid.

86
Q

What type of cell is the mature follicle?

A

Secondary oocyte

87
Q

What stage is the secondary oocyte arrested in?

A

Metaphase II

88
Q

What happens in the follicular phase?

A

Rising levels of FSH at the beginning saves the primary oocyte from atresia and LH rise causes production of estrogen. FSH and LH increase causes primary follicle -> secondary follicle-> tertiary follicle. At the end of the follicular phase, the tertiary follicle undergoes meiosis I to form secondary oocyte which is a mature follicle.

89
Q

What happens at the end of the follicular phase?

A

Mature follicle/ secondary oocyte forms by meiosis I

90
Q

When do oestrogen levels peak?

A

At the midfollicular phase

91
Q

When does oestrogen cause negative feedback on the menstrual cycle?

A

In the early follicular phase

92
Q

When does oestrogen cause postive feedback in the cycle?

A

End of follicular phase when there is high levels of oestrogen

93
Q

What causes LH surge?

A

High levels of oestrogen that cause positvie feedback cycle

94
Q

What causes the production of progesterone?

A

LH acting on corpus luteum

95
Q

What causes sloughing of the starcofunctionale?

A

Drop in progesterone levels due to no fertilisation results in blood vessels constrcting and preventing blood flow of oxgen to starcofunctionale and this results in necrosis of the layer.

96
Q

Why does the corpus luteum degrade?

A

No fertilisation

Year 1 (191 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions