Brainscape's Knowledge GenomeTM

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


See full index

MD3002 Physiology > Menstraul Cycle ans its jormonal control > Flashcards

Menstraul Cycle ans its jormonal control Flashcards

1
Q

How long is the menstraul cycle?

A

Mean 28 days (+/- 3.95) for about 40 years

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

When does menopause occur?

A

45 - 55 (average 51 years) and marks the end of natural fertility

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

What is Premature ovarian failure?

A

Menopause can occur in women under the age of 40 (idiopathic, autoimmune disorders, genetic disorders such as fragile X, chemotherapy, radiation)
- Symptoms can be treated with oestrogen replacement (hormone replacement therapy - HRT)

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

When does ovulation occur in the menstraul cycle?

A

14 days

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

What is the phase called before ovulation?

A

Follicular phase

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

What is the phase called after ovulation?

A

Luteal phase

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

At what point in the menstraul cycle does 1 follicle become dominant?

A

Day 7 - the dominant follicle then matures from day 7 to 14/ovulation

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

When in the menstraul cycle does the corpus luteum degenerate?

A

Day 25 - 28

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

What are the uterine phases and when do they occur?

A
  • Menstraul: day 1 - 5
  • Proliferative: day 5 - 13
  • Secretory: day 13 - 28
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the anterior pituitary gonadotropins?

A
  • LH

- FSH

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

What are the gonadal sex hormones?

A
  • Oestrogen

- Progesterone

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

What is in higher concentration in the plasma LH or FSH?

A

LH

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

Describe how FSH concentrations vary throughout the menstraul cycle?

A

Increases in early part of follicular phase, then steadily decreases throughout remainder of cycle EXCEPT small midcycle peak

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

Describe how LH concentrations vary throughout the menstraul cycle?

A

Constant during most of follicular phase, then large midcycle increase (LH surge) peaking ~18h before ovulation. Then rapid decrease with further slow decline during the luteal phase

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

Describe how oestrogen concentrations vary throughout the menstraul cycle?

A

Low and stable for 1st week, increases rapidly in 2nd weeks, starts to decline before LH peak. Then second increase due to corpus luteum in last few days of cycle.

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

Describe how progesterone concentrations vary throughout the menstraul cycle?

A

Low level due to ovary release during follicular phase with small increase just before ovulation. Soon after ovulation, large increase due to CL release, then similar pattern to oestrogen

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

Describe how inhibin concentrations vary throughout the menstraul cycle?

A

Similar pattern to oestrogen ie increases in late follicular phase, remains high during luteal phase, decreases as corpus luteum degenerates

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

How does oestrogen affect the concentrations of FSH and LH?

A
  • In low plasma concentrations, causes the anterior pituitary to secrete less FSH and LH in response to GnRH and also may inhibit the hypothalamic neurons that secrete GnRH
  • When oestrogen increases dramatically it causes anterior pituitary cells to secrete more LH and FSH in response to GnRH. Oestrogen can also stimulate the hypothalamic neurons that secrete GnRH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does inhibin affect FSH?

A

Inhibin acts on the pituitary to inhibit the secretion of FSH
(-ve feeback inhibition of FSH secretion throughout the cycle)

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

What inhibits the hypothalamic neurons that secrete GnRH?

A
  • High plasma concentrations of progestone, in the presence of oestrogen
  • Results in -ve feedback inhibition of FSH and LH secretion and prevention of LH surges during the luteal phase and pregnancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does FSH stimuate?

A
  • In the first week of the follicular phase it stimulates the growth of medium sized follicles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What cells express FSH receptors?

A
  • Granulosa cells of the ovary during the follicular phase of the menstraul cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are granulosa cells homologous to in men?

A

Sertoli cells of the testis

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

When does LH rise dramatically and what is it stimulated by?

A

12 hours before ovulation

- Stimulated by an increasing rate of secretion of oestrodiol-17B

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

What does LH stimulate by the corpus luteum?

A

Steroid hormone biosynthesis during the secretory phase

26
Q

What does LH do?

A

Stimulates Theca cells to synthesize androgens

27
Q

What is the main androgen produced?

A

Androstenedione

28
Q

What stimulates granulosa cells to convert androgens to estrogen?

29
Q

What is androstenedione converted to in granulosa cells?

A

Oestrodiol 17B

30
Q

What is the LH and FSH surge caused by?

A

MId-cycle shift of oestrogen from -ve to +ve feedback

- Caused by upregulation of receptors (eg GnRH in anterior pituitary) when oestrogen levels are increased

31
Q

What does the dominant follicle secrete?

A

Large amounts of oestrogen

- Acts on anterior pituitary (and possibly hypothalamus) to cause LH surge

32
Q

What does increased plasma LH stimulate?

A

Triggers ovulation and formation of corpus luteum

33
Q

What cells mediate the action of LH?

A

Granulosa cells

34
Q

What are the functions of the granulosa cells?

A
  • Nourish oocyte
  • Secrete chemical messangers that influence the oocyte and theca cells
  • Secrete antral fluid
  • Are the site of action for oestrogen and FSH in the control of the follcle development during early and middle follicular phases
  • Express aromatase, which converts androgen (from theca cells) to oestrogen
  • Secrete inhibin, which inhibits FSH secretion via an action on the pituitary
  • Are the site of action for LH induction of changes in the oocyte and follicle culminating in ovulation and formation of the corpus luteum
35
Q

WHat happens to LH and FSH levels in the luteal phase?

A

Suppressed

36
Q

What happen in the luteal phase if no implantation?

A
  • hCG does not appear in blood
  • CL dies
  • Progesterone and oestrogen decrease
  • Menstruation occurs and next MC begins
37
Q

What organ is the source of the timing of the menstraul cycle?

38
Q

What happens if progesterone remians high?

A
  • Levels of LH and FSH will be suppressed and ovulation will not occur
  • Occurs in pregnancy, human chorionic gonadotropin produced by placenta maintains corpus luteum which continues to secrete progesterone
39
Q

What hormone is exploited therapeutically in oral contraceptive pills?

A

Oestrogen

- Suppresses LH and FSH and prevents ovulation

40
Q

What happens in the menstraul phase?

A

Epithelail lining of uterus (endometrium) degenerates

41
Q

What happens during the proliferative phase?

A
  • Menstraul flow ceases
  • Under influence of oestrogen, endometrium thickens
  • Growth of unerlying smooth muscle (myometrium) also occurs
  • Synthesis of receptors for progesterone in endometrial cells also occus
  • Is part of ovarian folicular phase
  • Lasts for ~10 days until ovulation
42
Q

What happens during the secretory phase?

A
  • Begins soon after ovulation
  • Endometrium increases secretory activity under influence of progestone
  • Endometrial glands become coiled, filled with glycogen, blood vessels become more numerous, enzymes accumulate in glands and connective tissue, all to make endometrium a hospital environment for implantation and nourishment of developing embryo
  • Coincides with ovarian luteal phase
  • Spiral arteries develop alongside complex, hackshae shaped glands
  • Secretion in the glands is rich in glycoprotein sugars and amino acids
  • Enlargement of myometrial cells but depressed overall excitability
43
Q

When is the ischaemic phase (if included)?

A

At the end of the secretory phase

44
Q

What happens during the ischaemic phase / end of secretory phase?

A
  • Loss of steroid support
  • Constriction of spiral arteries
  • Ischaemia and collapse of endometrium
  • Seperation of basal and functional layers
  • Functional layer is shed as menstraul bleeding increase in neutrophils
45
Q

How many cycles are there for the average healthy woman?

46
Q

Why is there no clotting of menstraul blood?

A

Endogenous fibrinolytic activity

47
Q

What is the normal amount of blood produced during mensruation?

A

30 - 80 mls

48
Q

What is dysmenorrhoea?

A
  • Painful contractions

- 15% seek analgesia

49
Q

What are the effects of oestrogen?

A
  • Stimulates growth of ovary and follicles (local effects)
  • Stimulates growth of smooth muscle and proliferation of epithelial linings of reproductive tract
  • Stimulates external genitalia growth, particularly during puberty
  • Stimulates breast growth, particularly ducts and fat deposition during puberty
  • Stimulates female body configuration during puberty: narrow shoulders, broad hips, , female fat distribution (deposition on hips and breasts)
  • Fluid secretion from lipid - producing skin glands
  • Bone growth and cessation
  • Vascular effects
  • Feedback effects on hypothalamus and ant pituitary
  • Stimulates prolactin secretion but inhibits prolactin’s milk-inducing action on the breasts
  • Protects against atherosclerosis by effects on plasma cholesterol, blood vessels and blood clotting
50
Q

What are the effects of progesterone?

A
  • Converts the oestrogen-promed endometrium to an actively secreting tissue suitable for implantation of an embryo
  • Induces thick, sticky cervical mucus
  • Decreases contractions of fallopian tubes and endometrium
  • Decreases proliferation of vaginal epithelial cells
  • Stimulates breast growth, particularly glandular tissue
  • Inhibits feedback effects on hypothalamus and ant pituitary
  • Increases body temperature
51
Q

What is oligomenorrhoea?

A

Infrequent light periods

52
Q

What is metorrhagia?

A

Irregular bleeding

53
Q

What is dysmenorrhoea?

A
  • Painful periods
  • Main cause is overproduction of prostaglandins produced by endometrium in response to decrease in plasma oestrogen and progesterone
54
Q

What is polymenorrhoea?

A

Frequent periods

55
Q

What is amenorrhoea?

A

No periods

56
Q

What is premenstrual syndrome and premenstrual dysphoric disorder?

A
  • PMS - 75% of women who experience symptoms which affect their everyday quality of life
  • PMDD - 3-8% More serios can be temporarily disabling (eg anxiety, mood swings, tiredness, depression, headaches, abdo pain)
57
Q

What is thought to be the cause of some of the symptoms associated with PMDD and PMS?

A

Falling levels of progesterone at the end of the cycle - progesterone is thought to have an anxiolytic effect

58
Q

What are the primary causes of amenorrhoea?

A
  • Anatomical/congenital abnormality e.g underdevelopment or absence of uterus/vagina
  • Genetic e.g. Turner’s syndrome
59
Q

What are the secondary causes of amenorrhoea?

A
  • Pregnancy
  • Lactation
  • Exercise/nutrition
  • Menopause
  • Polycystic ovarian syndrome
  • Iatrogenic (surgery, medication)
60
Q

What is included in the female athlete triad?

A
  • Exercise
  • Nutrition
  • Amenorrhoea
61
Q

What is Lactational amenorrhea?

A

the temporary postnatal infertility that occurs when a woman is amenorrheic (not menstruating) and fully breastfeeding

MD3002 Physiology (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions