Lecture 5: Puberty Flashcards
What is the definition of puberty? (reproductively and clinically)
(Complex developmental event)
- Continuum of changes leading to somatic and sexual maturation
- Profound physiological, psychological and physical changes
(Reproductively - To produce mature gametes:)
- Testes= production of spermatozoa
- Ovaries= development of meiotically competent oocyte
(Clinically)
- Breast development in females, and increased testicular volume in males
What are the endocrine events of puberty?
- Adrenarche
- Gonadarche
What is adrenarche and how is it clinically presented?
- activation of adrenal androgens (dhea/s)
- associated with:
- growth of pubic hair,
- axillary hair
- growth in height.
Definition of gonadarche
- Activation of HPG axis to produce and secrete LH/FSH
What do the 2 gonadotrophin hormones cause in gonadarche?
LH: steroid synthesis -> secondary sex characteristics
FSH: growth of testes; steroid synthesis; folliculogenesis
Is adrenarche and gonadarche dependent on one another?
-No, they are independently regulated
i.e. one does not cause the other and one does not have to start for the other to start too.
Which endocrine process of puberty is first?
- Adrenarche
At what age does adrenarche occur?
- 6-8 years
What is adrenarche characterised by? / which hormones are reinstated?
- re-instigation of adrenal androgen secretion:
- Dehydrogenase-epiandrosterone (DHEA)
- Dehydrogenase-epiandrosterone sulphate (DHEA-S)
What changes occur in adrenarche hormonally?
- DHEA and DHEA-S secretion
- No change in cortisol/other adrenal hormones
Is the HPA axis activated during adrenarche?
- Yes, BUT not globally.
Where is DHEA and DHEA-S secreted from?
- Zona reticularis
Anatomy of the adrenal gland
Why are DHEA and DHEA-S reinstated?
- Inherent maturation of cellular compartments of the adrenal cortex
- i.e. remodelling of the adrenal cortex
What happens to the adrenal gland during the foetal development stage and which hormones are present?
- 2 zones only present: foetal zone and definitive zone
- DHEA/S production
What happens to the adrenal gland during the neonate developmental stage and which hormones are present?
- Involution of foetal zone (shrinkage of foetal zone)
- DHEA/S production