Lecture 20 - Sexual differentiation and Puberty Flashcards
What is puberty?
It describes the physiological, morphological and behavioural changes as the gonads change from infantile to adult forms.
What are definitive signs of boys and girls entering puberty?
menarche - first mentrual bleed in girls
First ejaculation in boys
What causes secondary sexual characteristics in girls and boys?
In girls ovarian oestrogens regulate growth of breast and female genetalia. Ovarian and adrenal androgens control pubic and axilla hair.
In boys testicular androgens cause growth of external genetalia and pubic hair growth. Also causes enlargement of larynx and voice deepening.
What do the tanner stages for boys and girls look at?
Look at size and shape of sexual organs aswell as pubic hair
How is onset of puberty recognised in boys and girls?
It is recognised in boys by testicular size and in girls through breast bud formation.
What is the order of the stages of puberty in girls?
Breast bud formation, then pubic hair then menarche.
What is precocious puberty?
Onset of sexual characteristics in girls under 8 and boys under 9.
What is delayed puberty?
Absence of secondary sexual characteristics by 14 in girls and 16 in boys
What is kisspetin and what role does it have in puberty?
It is a product of the gene Kiss 1, it is an essential ligand for the G protein coupled receptor GPR54 which is expressed in hypothalamic GnRH neurones. Loss of function causes failure to progress through puberty in men.
What is the endocrine mechanism underlying puberty?
Puberty generation is caused by an increase in hypothalamic GnRH. This causes release of the other hormones that cause puberty.
