Puberty

Question 1

Define adolescence.

Answer 1

Manifestation of changes in the brain in the form of change in behaviour.

Question 2

Which part of the brain is responsible for the start of puberty? and which hormones are involved?

Answer 2

Hypothalamus

Pulsatile GnRH → LH → gonads (testes/ovary) Leydig→ testosterone/oestrogen → target tissues for physical changes

Pulsatile GnRH → FSH → gonads Sertoli → ova/sperm

Question 3

What is the first sign of puberty in boys?

Answer 3

Testicular enlargement → >4mls

No growth spurt until 10-12mls

Question 4

What is the first sign of puberty in girls?

Answer 4

Breast development

Oestradiol → pubertal changes

Question 5

What is responsible for hair development in boys and girls?

Answer 5

Boys - testosterone

Girls - adrenal androgens

Question 6

What does oestrogen do for development in girls?

Answer 6

Breast development and fat deposition in hips

Increased uterus and vagina size and their secretions

Question 7

Which pubertal sex hormones for growth are released by actions of the hypothalamus? And which hormones are involved with their actions?

Answer 7

GH and IGF

Thyroid hormone → production and action of GH on tissues

Insulin → secretion of IGF, promotes protein synthsis

Question 8

How does growth end?

Answer 8

Fusion of epiphysis due to oestrogen

Question 9

What is given to induce puberty? and what property makes it appropriate?

Answer 9

Oxandrolone - no compromising effect as it is not converted to oestrogen.

Question 10

What is the pattern of growth for males?

Answer 10

Testicular growth → penile growth → pubic hair → growth spurt → voice drop/need to shave

Question 11

What is the pattern of growth for females?

Answer 11

Breast buds → pubic hair and growth spurt → mestruation

Question 12

How might non-consonant growth present?

Answer 12

Often virilization (development of male characteristics in females)

Pubic/axillary hair growth → no enlargement of testes/breasts

(women might also get cliteromegaly and increased height velocity with compromised final height)

Question 13

What BMI is required for puberty?

What % bw fat mass is required?

What % bw fat mass is needed for menarche?

Answer 13

17kg/m²

17%

22%

Question 14

What is adrenarche?

Answer 14

Adrenal Androgen production → pubic and axillary hair

Normally co-existent with normal puberty, but can precede by 1 year

No influence of FH/LSH

Question 15

What is gonadarche?

Answer 15

Onset of puberty caused by nocturnal (pulsatile) GnRH release → LH/FSH → increased testosterone/oestrogen