Flashcards in Repro - puberty and abnormalities of menstruation Deck (72)
When do changes in the male at puberty begin?
When do changes in the female at puberty begin?
What is adrenarche?
The onset of an increase in the secretion of androgens.
What is the first sign of puberty in males?
Genital development - testicular enlargement
What is the first sign of puberty in females
Breast bud (thelarche) development
What is the series of changes that occur in males at puberty?
1. Genital development begins
2. Pubic hair growth (puberarche)
3. Spermatogenesis begins
4. Growth spurt (~10cm/year)
5. Genitalia adult
6. Pubic hair adult
Describe the changes that occur to male pubic hair:
PH2: Sparse, pigmented, long, mainly along labia and base of penis
PH3: dark, coarse, curlier
PH4: filling out towards adult distribution
PH5: adult in quantity and type with spread to medial thighs
Describe the changes that occur to male genitalia:
G2: lenghening of penis
G3: further growth in length and circumference
G4: Development of glans penis, darkening of scrotal skin
G5: adult genitalia
What is the series of changes that occur in females at puberty?
1. Breast bud (thelarche) development
2. Pubic hair growth (puberarche)
3. Growth spurt (9cm/year)
4. Onset of menstrual cycles (Menarche)
5. Pubic hair adult
6. Breasts adult
Describe the changes that occur to breasts during puberty:
B2: Breast bud
B3: juvenial smooth contour
B4: Areolar and papilla project above breast
What causes the onset of puberty?
A steady rise in FSH and LH secretion caused by pulsatile GnRH secretion. This could be due to a reduction in sensitivity to the negative feedback by steroids but is more likely due to 'maturation' of central mechanisms e.g. the brain initiates it.
What is the most important factor in the timing of pubert?
What is the critical weight for menarche?
What may be the cause of secondary amenorrhoea with low body weight?
Reproductive cycle stops - this may be due to leptin signalling to the brain.
What is the rough growth spurt start weight in boys and girls?
Boys - 55kg
Girls - 30kg
What has happened to the average age of menarche in the last 200 years?
It has fallen - it used to be 17 and now it is 13 years. This is though to be because children are bigger now.
What cause puberarche?
Androgens in males and females. In females these androgens are from the adrenal glands.
Why are growth spurts shorter in females?
Oestrogen closes the epiphyses earlier in females. Oestrogen is needed to initiate the growth spurt, but once levels reach a certain point it causes epiphyses to fuse.
What is the difference between the growth spurts males experience versus females?
Males: longer and slightly faster
Females: earlier and shorter
What hormones does the growth spurt depend upon?
Growth hormone and steroids
What hormone is thelarche dependent upon?
What hormone is male genital development dependent upon?
What is precocious puberty?
The development of the signs of puberty before the age of 8 in girls and 9 in boys.
What is the cause of precocious puberty?
1. Unknown in the majority of cases
2. Neurological causes - early stimulation of central maturation giving early inappropriate GnRH secretion e.g. pineal tumours and meningitis
3. Uncontrolled gonadotrophin or steroid secretion e.g. hormone secreting tumours
What pre-menopause changes do woman experience?
1. Changes to their menstrual cycle: follicular phase shortens, with ovulation early or absent
2. Reduced fertility - though still possible to get pregnant
When do woman experience pre-menopause changes?
What hormonal changes occur in pre-menopause woman?
Less oestrogen and inhibin is secreted therefore reduced negative feedback occurs and FSH and LH levels rise.
What hormonal changes occur in the menopause?
Female has run out of follicles therefore:
1. Oestrogen and inhibin levels fall dramatically
2. Negative feedback lost and therefore GnRH, FSH and LH levels increase
What is the menopause?
Cessation of the menstrual cycle for 12 months.