Menstrual cycle

Question 1

What is the purpose of the menstrual cycle?

Answer 1

generate oocyte

facilitate fertilisation

optimise endometrium for implantation

protect developing embryo

Question 2

On what day does ovulation occur?

Answer 2

14

Question 3

On what days does the follicular phase take place? (thinking about the cycle from the follicular perspective)

Answer 3

1-14

follicle generation takes place

Question 4

On what days does the luteal phase take place?

thinking about the cycle from the follicular perspective

Answer 4

14-28

formation and degradation of corpus luteum takes place

Question 5

What are days 1-5 of the menstrual cycle known as (from an endometrial perspective)?

Answer 5

Menstrual phase

Question 6

What are days 5-14 of the menstrual cycle known as (from an endometrial perspective)?

Answer 6

Proliferative phase

Question 7

What are days 14-28 of the menstrual cycle known as (from an endometrial perspective)?

Answer 7

secretory phase

Question 8

What are the prominent hormones produced in follicular phase?

Answer 8

FSH - pituitary

oestrogen - ovary

Question 9

What are the prominent hormones produced in luteal phase?

Answer 9

LH - pituitary

progesterone - ovary

Question 10

What does HPO stand for?

Answer 10

hypothalamo-pituitary-ovarian

axis

Question 11

What is the main oestrogen that is important during 1)reproduction, 2) pregnancy and 3) post menopause?

Answer 11

1) estradial (E2)
2) E3
3) E1

Question 12

What are the different ways the cycle can be broken down in to phases?

Answer 12

From the follicular perspective:
follicular phase (days 1-14)
luteal phase (days 14-28)

From the endometrial perspective:
menstrual phase (days 1-5)
Proliferative phase (days 5-14)
Secretory phase (days 14-28)

Question 13

How is the menstrual cycle controlled?

Answer 13

Hypothalamo-pituitary-ovarian axis

Question 14

What hormone, important to the menstrual cycle, is released by the hypothalamus?

Answer 14

GnRH

Question 15

What hormones, important to the menstrual cycle, are released by the anterior pituitary?

Answer 15

FSH and LH

Question 16

How does the GnRH effect the menstrual cycle?

Answer 16

stimulates anterior pituitary gland to produce FSH and LH

Question 17

How do FSH and LH effect the menstrual cycle?

Answer 17

stimulate ovary to produce oestrogen

Question 18

How does oestrogen effect the hypothalamus and the anterior pituitary gland? What is the exception to this?

Answer 18

negative feedback, causes reduced release of GnRH, FSH and LH

On day 14 (ovulation), very high levels of E2, which cause v. high levels of LH (triggering ovulation)

Question 19

What is important about the way GnRH is released?

Answer 19

Hourly pulses - v. important

Question 20

How is GnRh transported to pituitary?

Answer 20

hypophyseal portal blood system

Question 21

What can cause alteration of GnRH secretion?

Answer 21

bereavement
anxiety
time zone
day/night duty
exercise
weight loss/gain

Question 22

What factors can alter the menstrual cycle?

Answer 22

bereavement
anxiety
time zone
day/night duty
exercise
weight loss/gain

Question 23

What hormone, important in reproduction (but especially birth), is produced in the posterior pituitary gland?

Answer 23

oxytocin

Question 24

What cells in the anterior pituitary gland produce FSH and LH?

Answer 24

basophils

Question 25

What does FSH do in the menstrual cycle?

Answer 25

Stimulates follicular activity - promotes estradiol (oestrogen) production from granulose cells

Question 26

What does LH do in the menstrual cycle?

Answer 26

triggers release of egg from dominant follicle promotes development of corpus luteum and production of progesterone

Question 27

What happens when oestrogen levels peak on day 14/mid-cycle?

Answer 27

High E2 levels = surge in LH = ovulation

Question 28

What happens to the follicle in the menstrual cycle?

Answer 28

develops and matures in ovary, released during ovulation, becomes corpus luteum degenerates if not fertilised 1) primordial follicle 2) primary/preantral follicle 3) secondary/antral follicle 4) preovulatory follicle 5) ovulation

Question 29

What happens to the corpus luteum post-ovulation, if no fertilisation has taken place?

Answer 29

degenerates/fibroses to become corpus albicans

Question 30

What is the endometrium?

Answer 30

Lining of uterus

Question 31

What happens to the endometrium in the proliferative phase? What hormone causes this?

Answer 31

Endometrium thickens (by ovulation 2-3mm thick) Increase stroll cells Increased glands, blood cells E2

Question 32

Roughly how thick is the endometrium by ovulation?

Answer 32

2-3mm

Question 33

What happens to endometrium in secretory phase? Which hormone is dominant?

Answer 33

Increased secretion Increased lipid and glycogen Increased blood supply Endometrium 4-6mm thick OPTIMAL CONDITIONS FOR IMPLANTATION OF FERTILISED EGG: STABLE, VASCULAR AND NUTRIENT-RICH Progesterone

Question 34

Roughly how thick is the endometrium during secretory phase?

Answer 34

4-6mm

Question 35

What occurs in menstruation?

Answer 35

LH levels fall Corpus lutes collapses progesterone withdrawal = menstruation begins vasodilation necrotic outer layers of endometrium separate from uterus separated tissue and blood initiate uterine contractions expel contents

Question 36

How does a follicle reach the fallopian tube?

Answer 36

released by ovary, collected by fallopian tube by chemotaxis

Question 37

Where is mucus produced?

Answer 37

cervix - columnar glands

Question 38

What is the consistency of cervical mucus around ovulation? How does this facilitate conception?

Answer 38

Stringy and runny (spinnbarkeit) Facilitates sperm access during ovulation - the consistency changes after this, to prevent infection

Question 39

What is the consistency of cervical mucus in the luteal phase? How does this facilitate pregnancy?

Answer 39

Tenacious and inelastic prevents microbial ingress - protects developing embryo critical to pregnancy - mucus plug

Question 40

How can a malformed mucus plug effect pregnancy? What can cause this?

Answer 40

Can lead to miscarriage and pre-term birth surgery or other problem that has damaged endothelial lining of cervix

Question 41

Between what days are you at most risk of getting pregnant?

Answer 41

7-21 Actually a very wide period of time where risk of pregnancy is high. RHYTHM METHOD OF CONTRACEPTION DOES NOT WORK

Question 42

What does the combined oral contraceptive contain?

Answer 42

Estradiol | Progestogen (synthetic progesterone)

Question 43

how does the COCP effect the menstrual cycle to prevent pregnancy?

Answer 43

Steady (but higher) levels of oestrogen and progesterone inhibit GnRH/FSH/LH prevent ovulation thin endometrium tenacious mucus

Question 44

When is the worst time to forget to take pill?

Answer 44

at the beginning or end of 3 week cycle - extends time with no cover, therefore time for GnRH/FSH/LH levels to rise again

Question 45

How are eggs collected in IVF?

Answer 45

Superovulation

Question 46

How is super ovulation induced in IVF?

Answer 46

daily injections of recombinant FSH