Brainscape's Knowledge GenomeTM

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


See full index

Yr 2 - Reproductive System > Intro and Menstrual Cycle > Flashcards

Intro and Menstrual Cycle Flashcards

1
Q

What is the purpose of the menstrual cycle?

A
  • Generate oocyte
  • Facilitate fertilisation
  • Optimise endometrium for implantation
  • Protect developing embryo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the endocrine control of the menstrual cycle?

A

Hypothalamus, anterior pituitary and ovaries work together

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

What is the name of the first menstrual cycle?

A

Menarche

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

What does the hypothalamus release during menstrual cycle?

A

GnRH

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

How does GnRH act?

A

Exerts effect on anterior pituitary –> stimulates release of FSH and LH

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

What does LH stand for?

A

Luteinising hormone

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

What does FSH stand for?

A

Follicular stimulating hormone

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

What does FSH and LH act on?

A

Ovary to release oestrogens (this feeds back to hypothalamus and anterior pituitary)

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

What part of the hypothalamus is GnRH secreted by?

A

Mid basal hypothalamic neurons

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

How is GnRH transported to the pituitary?

A

Via hypophyseal portal blood system

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

What is GnRH secretion affected by?

A 
bereavement
anxiety
time zone
day/night duty
exercise
weight loss/gain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What cells of the anterior pituitary secrete FSH and LH?

A

Basophils

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

What type of molecules are FSH and LH?

A

Glycoproteins

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

What does FSH stimulate?

A

Stimulates follicular activity, thus promoting estradiol production from granulosa cells

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

What does LH stimulate?

A

Triggers release of egg from dominant follicle

Promotes development of the corpus luteum and the production of progesterone

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

What is the predominant gonadotropin during the 1st half oF the cycle?

A

FSH

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

GnRH, LH and FSH production is inhibited by rising E2 levels.

When is there an exception to this?

A

Near midcycle when high levels of E2 lead to a surge in LH release which triggers ovulation

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

What E2?

A

Oestradiol –> Major female sex hormone (strongest of the 3 naturally produced oestrogens)

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

What are the first class of follicles formed in ovaries?

A

Primordial follicles

  • In fetus at 6 months: 2,000,000
  • At birth: 750,000
  • At puberty 400,000

Approx 450 follicles develop and produce an egg; remainder degenerate

No new follicles produced

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

Describe the sequence in which the egg is produced before ovulation

A
  1. Primordial follicle
  2. Primary/preantral follicle
  3. Secondary/antral follicle
  4. Preovulatory follicle
  5. Ovulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the phases of the ovarian cycle?

A
  1. Follicular phase
  2. Ovulation
  3. Luteal phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the follicular phase?

A

Marks the beginning of a new cycle as follicles (oocytes surrounded by stromal cells) begin to mature and prepare to release an oocyte.

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

What are follicular cells also known as?

A

Granulosa cells

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

Where do granulosa cells lie?

A

Directly around the oocyte zone pellucida and are released with the oocyte at ovulation

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

Describe a primordial follicle

A

Cconsist of an oocyte surrounded by a single layer of flattened granulosa cells

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

Describe the follicular development

A
  1. Proliferation of granulosa cells: antrum develops (fluid)
  2. Gap junctions and cytoplasmic processes between oocyte and granulosa cells allows communication and passage of low mol wt materials (e.g.nutrients)
  3. Proliferation of theca cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are theca cells?

A

The endocrine cells associated with ovarian follicles that play an essential role in fertility by producing the androgen substrate required for oestrogen biosynthesis.

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

Describe the theca interna cells

A

Glandular and highly vascularised.

Express receptors for luteinising hormone (LH).

Secrete androgens.

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

Describe the theca externa

A

Fibrous capsule

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

After the follicle ruptures, what do the theca interna cells differentiate into?

A

The theca lutein cells of the corpus luteum.

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

What are the androgens secreted by the theca interna cells converted to? Where?

A

Converted to oestradiol in granulosa cells

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

Describe the ovarian hormone production at the beginning of the cycle (menses)

A

There is little ovarian hormone production and the follicle begins to develop independently of gonadotropins or ovarian steroids.

33
Q

What do the low steroid and inhibin levels at the beginning of the cycle cause? Why?

A

There is little negative feedback at the HPG axis resulting in an increase in FSH and LH levels. These stimulate follicle growth and oestrogen production.

34
Q

What do almost mature follicles release? What does this then stimulate?

A

High levels of oestrogens

Stimulates release of more GnRH and LH

GnRH then promotes release of FSH and even more LH

35
Q

How many follicles can continue to maturity? What do the other follicles form?

A

Only one

Polar bodies

36
Q

As follicular oestrogen eventually becomes high enough to initiate at the HPG axis, what happens?

A

Causes increasing levels of GnRH and gonadotropins.

However, the effect is only reflected in LH levels (the LH surge).

37
Q

What is the LH surge due to?

A

Due to the increased follicular inhibin, selectively inhibiting FSH production at the anterior pituitary.

Granulosa cells become luteinised and express receptors for LH.

38
Q

What is the HPG axis?

A

Connection between the hypothalamus, pituitary gland, and gonads.

39
Q

Describe the production of inhibin

A

FSH stimulates the secretion of inhibin from the granulosa cells of the ovarian follicles in the ovaries. In turn, inhibin suppresses FSH

40
Q

What does the LH surge bring about?

A

Ovulation

41
Q

What happens to the follicle in response to the LH surge?

A

It ruptures and the mature oocyte is assisted to the fallopian tube by fimbria.

Here it remains viable for fertilisation for around 24 hours.

42
Q

Following ovulation, what does the follicle secrete?

A

Secreting oestrogen and now also progesterone

43
Q

What is the effect of the secretion of oesotrogen and progesterone by the follicle? What is purpose of this?

A

-ve feedback on HPG axis

This, together with inhibin (inhibits FSH) stalls the cycle in anticipation of fertilisation.

44
Q

What is the corpus luteum? What does it produce?

A

The tissue in the ovary that forms at the site of a ruptured follicle following ovulation.

It produces oestrogens, progesterone and inhibin to maintain conditions for fertilisation and implantation.

45
Q

If no fertilisation occurs, what happens to the corpus luteum?

A

Degenerate/fibroses to become corpus albicans

46
Q

As the corpus luteum regresses, what happens to the hormone levels?

A

Fall significantly, relieving negative feedback, resetting the HPG axis ready to begin the cycle again.

47
Q

What is the endometrium?

A

The lining layer of the uterus

48
Q

What are the phases of the uterine cycle?

A
  1. Proliferative phase (runs alongside follicular phase)
  2. Secretory phase (runs alongside luteal phase)
  3. Menses
49
Q

What does menses mark?

A

Beginning of new menstrual cycle

50
Q

Describe the endometrium during the proliferative phase?

A

Effects of oestradiol:

  • Endometrium thickens
  • Increased stromal cels
  • Increased glands, blood vessels

By ovulation, endometrium is 2-3mm thick

51
Q

What else does oestradiol initiate during proliferative phase?

A

Fallopian tube formation, thickening of the endometrium, increased growth and motility of the myometrium and production of a thin alkaline cervical mucus (to facilitate sperm transport).

52
Q

What else does oestradiol initiate during proliferative phase?

A

Fallopian tube formation, thickening of the endometrium, increased growth and motility of the myometrium and production of a thin alkaline cervical mucus (to facilitate sperm transport).

53
Q

What is the predominant hormone during the 2nd half of the cycle?

A

Progesterone

54
Q

Describe the secretory phase

A

Progesterone stimulates further thickening of endometrium

Increased secretion
Increased lipids and glycogen
Increased blood supply

55
Q

Describe the endometrium at the end of the secretory phase

A

Optimal conditions for implantation of fertilised egg: stable, vascular, nutrient-rich

56
Q

What happens during menstruation?

A

Corpus luteum has broken down and the internal lining of the uterus is shed

57
Q

How does the uterus lining shed?

A

Necrotic outer layers of endometrium separate from uterus

Separated tissue and blood initiate uterine contractions –> expel contents

58
Q

What is produced by the cervix?

A

Mucus production from columnar glands

59
Q

Describe the mucus produced by the cervix midcycle? What is purpose of this?

A

Stringy and runny midcycle

Facilitates sperm access at ovulation

60
Q

Describe the mucus produced by the cervix in the luteal phase? What is purpose of this?

A

Tenacious and inelastic in luteal phase

  • Prevents microbial ingress protects developing embryo
  • Critical to pregnancy (mucus ‘plug’)
61
Q

What does the combined oral contraceptive contain?

A

Oestradiol and a progestagen

62
Q

What is progestagen?

A

A synthetic progesterone

63
Q

What does the combined oral contraceptive do?

A

Inhibits GnRH/FSH/LH to prevent ovulation.

Thin endometrium.

Tenacious and inelastic mucus.

64
Q

Describe the effects of FSH in the menstrual cycle

A

Binds to granulosa cells to stimulate follicle growth, permit the conversion of androgens (from theca cells) to oestrogens and stimulate inhibin secretion

65
Q

Describe the effects of LH in the menstrual cycle

A

LH acts on theca cells to stimulate production and secretion of androgens

66
Q

What are the effects of moderate oesotrogen levels on the HPG axis?

A

Negative feedback

67
Q

What are the effects of high oesotrogen levels on the HPG axis (in the absence of progesterone)?

A

Positively feedback on the HPG axis

68
Q

What are the effects of oesotrogen on the HPG axis in the presence of progesterone?

A

Negative feedback on the HPG axis

69
Q

What are the effects of inhibin?

A

Selectively inhibits FSH at the anterior pituitary

70
Q

What is only hormone with positive feedback effect on HPG axis?

A

Oestrogen (LH surge)

71
Q

What day is ovulation?

A

Around day 14

72
Q

What is the Tanner Scale?

A

Scale of physical development in children, adolescents and adults (puberty scale)

73
Q

How many stages are there in the Tanner Scale?

A

5

74
Q

Describe stage 1 in Tanner Scale

A

Preadolescent, no sexual hair

No boobs for females

75
Q

Describe stage 2 in Tanner Scale

A

Sparse, pigmented, long straight hair along labia and at base of penis

Breast budding (areola and papilla)

76
Q

Describe stage 3 in Tanner Scale

A

Darker, coarser, curlier hair

Continued enlargement of breats

77
Q

Describe stage 4 in Tanner Scale

A

Adult but decreased distribution (hair)

Areola and papilla form secondary mound

78
Q

Describe stage 5 in Tanner Scale

A

Adult in quantity and type with spread to medial thighs

Mature female breast

Yr 2 - Reproductive System (30 decks)

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