Puberty

Question 1

When are primary characteristics present? (1)

Answer 1

At birth

Question 2

When do secondary characteristics develop? (1)

Answer 2

At puberty

Question 3

What happens in the adolescent growth spurt? (3)

Answer 3

Interaction b/w growth hormone & oestrogen
Low levels of oest. - linear growth & bone maturation
High levels of oest. - epiphyseal fusion (stop growth @ ends of bones)

Question 4

What are the 2 major endocrinological events of puberty? (2)

Answer 4

Adrenarche

Gonadarche

Question 5

What is puberty? (4)

Answer 5

Complex developmental event
Continuum of changes leading to somatic & sexual maturation
Profound physiological, psychological changes
Breast development in females & increased testicular volume in males

Question 6

From a reproductive perspective, what is the goal of puberty? (1)

Answer 6

Produce mature gametes (oocytes & spermatozoa)

Question 7

What are the psychological changes of puberty? (4)

Answer 7

Increasing need for independence
Increased sexual awareness/interest
Development of sexual personality
The later the maturation, the better the adjustment

Question 8

What events occur in the CNS to bring on puberty? (7)

Answer 8

Change in inherent GnRH release
Body fat/nutrition
- anorexogenic (POM/CART neurones stimulated by leptin & insulin, following food intake to inhibit further food intake)
- orexogenic (AGRP, NPY neurones stimulated by ghrelin, or inhibited by leptin, following fasting to stimulate further food intake)
Steroids feed back onto GnRH & kisspeptin neurones
Activating mutations of kisspeptin (early/overactive GnRH neurones) - precocious puberty
Inactivating mutations of kisspeptin (abnormal GnRH neurones) - hypogonadotrophic hypogonadism (failure to enter puberty)
Environmental factors (photoperiod/seasonal) which may be processed by kisspeptin neurones to GnRH neurones

Question 9

How are puberty & body fat mass linked? (3)

Answer 9

Body fat mass (energy excess) impacts timing of puberty in both sexes
BMI >30 - 8x more likely to have sub/infertility
Anorexia/malnutrition/intense physical training - reduced response to GnRH causing reduced gonadotrophin levels causing amenorrhoea (until nourished/exercise stops)

Question 10

What is adrenarche? (2)

Answer 10

Adrenarche starts ~6-8yrs old
Increased adrenal androgen secretion
Adrenal androgens are produced in the ZR (functional ZR @ ~6yrs due to inherent maturation of the adrenals
Increase in dehydro-epian