Reproduction 3 - Puberty

Question 0

Describe female changes at puberty

Answer 0

o Breast bud (Thelarche) – the first sign that puberty has begun.
o Pubic hair growth (Adrenarche)
o Growth spurt (9cm/year)
o Onset of menstrual cycles (Menarche)
o Pubic hair adult
o Breasts adult

Question 1

Describe male changes at puberty

Answer 1

o Genital development begins
o Pubic hair growth (Adrenarche)
o Spermatogenesis begins
o Growth spurt (10cm/year)
o Genitalia adult
o Pubic hair adult

Question 2

What control is puberty under?

Answer 2

Puberty is under hormonal control; the start of puberty is associated with a steady rise in FSH and LH secretion.

Question 3

How does the brain initiate puberty?

Answer 3

o Pulsatile GnRH secretion leads to rise in FSH and LH
o Rise in GnRH could be reduction in sensitivity to –‘ve feedback by steroids, or (more likely) due to ‘maturation’ of central mechanisms

Question 4

What is the critical body weight for menarche?

Answer 4

o Critical weight is 47kg for menarche

If body weight falls significantly below this the reproductive cycle ceases (may be signalled to the brain by leptins)

Question 5

What is the growth spurt start weight in boys and girls?

Answer 5

Growth spurt start weight is 30kg for girls and 55kg for boys

Question 6

Why is puberty much earlier in western countries?

Answer 6

▪ Children much bigger

▪ Average age of menarche was seventeen 200 years ago compared with thirteen now.

Question 7

What is the term for pubic and axillary hair? What does it depend on?

Answer 7

Adrenarche - Depends on androgens in both sexes (From adrenal glands in girls)

Question 8

How does the growth spurt differ between men & women?

Answer 8

o Earlier and shorter in girls

o Men are larger as growth spurt is longer and slightly faster

Question 9

What does the growth spurt depend on?

Answer 9

Growth Hormone and Steroids in both sexes

Question 10

What marks the end of the growth spurt? How does this differ in girls and why?

Answer 10

o Ended in both sexes by epiphyseal fusion

o Oestrogen closes epiphyses earlier in girls. Oestrogen is needed to initiate the growth spurt, but once levels reach a certain point it causes the epiphyses to fuse.

Question 11

What is the term for breast development?

Answer 11

Thelarche

Question 12

What hormone is responsible for thelarche (breast development)?

Answer 12

Oestrogen

Question 13

What hormone is involved in male genital development?

Answer 13

Testosterone

Question 14

Why don’t most parts of the reproductive system work before puberty? What is this a result of?

Answer 14

Hormone levels are too low. This is a result of low GnRH secretion.

Question 15

Name two causes of precocious puberty and provide examples of each.

Answer 15

Majority of causes not known, However it can be due to:

o Neurological causes. Early stimulation of central maturation giving early, inappropriate GnRH secretion
▪ Pineal tumours
▪ Meningitis

o Uncontrolled Gonadotrophin or steroid secretion
▪ Hormone secreting tumours

Question 16

What age is the pre-menopause phase and the menopause

Answer 16

Pre-menopause >40 years

Menopause ~49-50 years

Question 17

What happens to the follicular phase pre-menopause?

Answer 17

Shortens with ovulation early or absent

Question 18

Why are there changes in the menstrual cycle pre menopause?

Answer 18

Less oestrogen secreted
▪ Less –‘ve feedback, so LH and FSH levels rise
▪ FSH rises more due to loss of Inhibin too

Question 19

What happens to fertility pre-menopause

Answer 19

Reduced fertility, though still possible to get pregnant

Question 20

What happens at menopause?

Answer 20

o Cessation of menstrual cycles
o Female has run out of follicles
o Oestrogen levels fall dramatically

Question 21

What is the impact of the dramatic fall in oestrogen at menopause on LH & FSH

Answer 21

▪ Less –‘ve feedback, so LH and FSH levels rise

▪ FSH rises dramatically due to loss of Inhibin too

Question 22

Outline some vascular effects of menopause. How are they relieved?

Answer 22

o Hot flushes affect ~80% to some degree
o Transient rises in skin temperature and flushes

o Oestrogen treatment

Effects of the Menopause
Vascular
o Hot flushes affect ~80% to some degree

Question 23

What is the effect of dramatically low oestrogen (menopause) on the uterus?

Answer 23

o Uterus
▪ Regression of endometrium
▪ Shrinkage of myometrium
▪ Shrinks away into a very small organ

Question 24

What other effects does menopause have on oestrogen sensitive tissues? (other than uterus)

Answer 24

o Thinning of cervix
o Vaginal rugae lost - Thinner, less distensible
o Involution of some breast tissue
o Changes in skin
o Reduction in bladder tone

Question 25

What is the effect of menopause on bone? Why?

Answer 25

o Oestrogen inhibits osteoclasts. A lack of oestrogen therefore leads to increased reabsorption relative to production

o Osteoporosis
▪ Much greater in some than others
▪ Major reason for fractures in later life
▪ Can be limited by Oestrogen therapy

Question 26

How is hormone replacement therapy administered?

Answer 26

o Orally or topically by patch or gel

Question 27

What is amenorrhoea?

Answer 27

Absence of periods for at least 6 months

Question 28

What is the difference between primary and secondary amenorrhoea?

Answer 28

o Primary Amenorrhoea – Never had a period. Absence of menses by age 14 with absence of Secondary Sexual Characteristics (SSC) e.g. breast development or absence by age 16 with normal SSC

o Secondary Amenorrhoea – Established menstruation has ceased for three months in a woman with a history of regular cyclic bleeding, or nine months in a woman with a history of irregular periods. Normally in women aged 40-55.

Question 29

What is the name given to infrequent periods occurring at intervals of 35 days – 6 months

Answer 29

Oligomenorrhoea

Question 30

What is Dysmenorrhoea?

Answer 30

Painful periods

Question 31

How would someone with Menorrhagia present?

Answer 31

Heavy periods. Excessive (>80ml), prolonged (> 7 day) uterine bleeding

Question 32

What is cryptomenorrhoea?

Answer 32

Periods occur but not visible due to obstruction in outflow tract

Question 33

What is dysfunctional uterine bleeding? (DUB)

Answer 33

Abnormal bleeding, no obvious organic cause.

Question 34

What are the origins of amenorrhoea?

Answer 34

• Hypothalamic/Pituitary,
• Ovarian
  or - Outflow tract (uterus, vagina, cervix)

Question 35

Why do some men develop breasts? What is this called?

Answer 35

Testosterone can be converted to oestrogen (which is responsible for breast development).

Gynaecomastia

Question 36

What is the underlying cause of menopause?

Answer 36

Ovaries run out of ova

Question 37

Why is FSH higher than LH in menopausal women?

Answer 37

No inhibin being produced by ovaries

Question 38

What are benefits of HRT?

Answer 38

o Relieves symptoms of the menopause
o Reduction in vasomotor symptoms
o Improvement in quality of life
o Improvement of urogenital symptoms
o Reduction in osteoporosis risk - but no longer recommended for first line protection (Bisphosphonates now recommended)

Question 39

What are risks of HRT?

Answer 39

o Venous thromboembolism (VTE)
o Stroke
o Breast cancer
o Endometrial, ovarian & colorectal cancer

Question 40

What is bone age? How can it be measured?

Answer 40

Bone age is the degree of maturation of a child’s bones.

XRays; measure growth plates. Different carpel bones fuse at different ages.