Female Hormonal Control of Reproduction and Infertility

Question 1

what are the 4 phases of the menstrual cycle?

Answer 1

• menstruation
• follicular phase
• ovulatory phase
• luteal phase

Question 2

how long is the menstruation phase meant to last?

Answer 2

4-5 days

Question 3

how long is the follicular phase?

Answer 3

10-16 days

Question 4

how long is the ovulatory phase?

Answer 4

36 hours

Question 5

how long is the luteal phase?

Answer 5

14 days

Question 6

what is the menarche?

Answer 6

date of first period

Question 7

what is menopause?

Answer 7

date of last period

Question 8

which menstrual regulating hormones does the hypothalamus release?

Answer 8

• Gonadotrophin-Releasing Hormone (GnRH)

- LHRH (luteinising hormone releasing hormone)

Question 9

which menstrual regulating hormones does the anterior pituitary release?

Answer 9

• Follicle stimulating hormone (FSH)

- Luteinising hormone (LH)

Question 10

which menstrual regulating hormones does the ovary release?

Answer 10

Oestradiol & Progesterone (steroids)

Question 11

what happens during puberty?

Answer 11

• integration of biological signals
• release of hormones
• Breasts and uterus develop
• Pubertal growth ‘spurt’
• Emotional changes

Question 12

where are most oocytes produced?

Answer 12

in utero

Question 13

what is ovulation a result of?

Answer 13

inter-relationships between

• hypothalamus
• anterior pituitary
• Ovaries

Question 14

how is the menstrual cycle regulated?

Answer 14

• gonadotrophin releasing system

- ovarian hormones

Question 15

what is the gonadotrophin releasing system responsible for?

Answer 15

• hypothalamic control LHRH

- LH and FSH; pulsatile release

Question 16

what are the 2 main steroids produced by the ovaries?

Answer 16

• oestrogens (oestradiol)

- progestogens (progesterone)

Question 17

what is the oestrogen responsible for?

Answer 17

• Endometrial proliferation
• Secretion of clear (receptive) cervical mucus
• Cause maturation of vaginal epithelium
• Negative feedback on the hypothalamus / pituitary (follicular phase)
• Positive feedback on the hypothalamus and pituitary (ovulatory phase)

Question 18

what are the effects of oestrogen on other systems?

Answer 18

• Maintenance of bone mass (both sexes)
• Effects on CNS (both sexes)
• Effects on vasculature (both sexes)
• Effects on lipid metabolism
• Effects on fat distribution
• Effects on blood clotting (thrombosis)
• Promote insulin secretion

Question 19

what secretes progesterone?

Answer 19

corpus luteum

Question 20

what are the effects of progesterone?

Answer 20

• Causes body temperature to rise
• Causes change to thick (non-receptive) cervical mucus secretion
• Down regulates oestrogen receptors
• Exerts a negative feedback control on the hypothalamus and pituitary

Question 21

what does FSH act on?

Answer 21

acts on primary and secondary follicles

Question 22

what does FSH cause?

Answer 22

follicular growth

Question 23

what does FSH promote?

Answer 23

oestradiol secretion from follicles

Question 24

what causes negative feedback on FSH?

Answer 24

Oestradiol / inhibin causes negative feedback on FSH

Question 25

what initiates ovulation?

Answer 25

By day 12 oestradiol achieves threshold to switch to positive feedback

Question 26

what happens during the luteal phase?

Answer 26

Residual follicular cells luteinise – corpus luteum

Question 27

what happens during late luteal phase?

Answer 27

corpus luteum involutes (invaded by macrophages)

Question 28

what does corpus luteum secrete?

Answer 28

oestradiol and progesterone

Question 29

what happens to estradiol and progesterone levels after the late luteal phase?

Answer 29

Oestradiol and progesterone fall

Question 30

what happens if fertilisation occurs?

Answer 30

- ovum implants - secretes hCG - hCG maintains corpus luteum - secretes estradiol and progesterone - pregnancy established

Question 31

what is precocious puberty?

Answer 31

starts before the age of 8 years

Question 32

what causes precocious puberty?

Answer 32

- LH/FSH driven - - brain tumour - - idiopathic (Clock error!) - oestrogen driven - - ovarian tumour

Question 33

what can cause delayed puberty?

Answer 33

- 'constitutional’ delay - hypothalamic disease - ovarian disease - pituitary disease - chronic illness

Question 34

what are some reasons for abnormal ovarian stimulation?

Answer 34

- hypothalamic disease - pituitary disease - Polycystic ovary syndrome

Question 35

what are some reasons for abnormal ovarian suppression?

Answer 35

- contraception | - endometriosis

Question 36

what can cause LHRH deficiency?

Answer 36

- Anorexia /bulimia (critical weight!) - Stress, exams, bereavement, exercise - Chronic illness, thyroid, anaemia etc, - Brain tumours - Cranial irradiation

Question 37

what can be reasons that cause hypopituitarism?

Answer 37

- Sheehan’s syndrome (postpartum haemorrhage) - Trauma - Autoimmune - Idiopathic - Haemochromatosis - Secondary tumours

Question 38

what are some diseases associated with pituitary tumours?

Answer 38

- non-secreting - ACTH (Cushing’s) - Growth hormone (Acromegaly) - Prolactin (hyperprolactinaemia) - Secondary tumours

Question 39

what are the types of ovarian related disease?

Answer 39

- Ovarian dysgenesis - LH/FSH receptor defects - Abdominal irradiation (cancer) - Premature menopause < 40 (autoimmune) - Menopause

Question 40

what are symptoms of polycystic ovary syndrome?

Answer 40

Hirsutism, menstrual irregularity, infertility, acne

Question 41

what is the effect of polycystic ovary syndrome on the hormones?

Answer 41

- high LH : LH/FSH ratio - Low - normal FSH - High androgens

Question 42

which gland secretes prolactin?

Answer 42

pituitary

Question 43

what happens if there are high levels of prolactin?

Answer 43

- inhibits ovulation | - Cause irregular /absent menstruation

Question 44

where are prolactin receptors found?

Answer 44

in ovary

Question 45

what regulates prolactin?

Answer 45

Under negative control by hypothalamic dopamine

Question 46

what is hyperprolactinaemia associated with?

Answer 46

pituitary tumour

Question 47

what can correct hyperprolactinaemia?

Answer 47

dopamine agonists | e.g. bromocryptine, cabergoline (very effective)

Question 48

how is LHRH released?

Answer 48

Natural ‘pulsatile’ release

Question 49

what does pulsed administration of LHRH result in?

Answer 49

100ug 90 minutes | promotes LH/FSH release

Question 50

what does continuous administration of LHRH result in?

Answer 50

- Down regulates pituitary LHRH receptors | - Blocks LH/FSH release

Question 51

how is hypothalamic amenorrhoea treated?

Answer 51

- Treated with LHRH ‘pump’ | - Also treated LH (hCG) FSH (recombinant)