T2 L7: Puberty physiology and disorders Flashcards
What is the definition of puberty?
The stage of physical maturation in which a person becomes physiologically capable of pro-creation
What are the 5 stages of puberty in a girl and at what age do they occur normally?
- Growth spurt 8-14yrs
- Breast growth 8-13yrs (Thelarche)
- Pubic hair 9-13yrs (Pubarche)
- Axillary hair 9.5-15yrs (Adrenarche)
- Menstruation 10-16yrs (Menarche)
When is it considered true puberty in girls?
When their is protrusion of the areola and breast growth
What are some endocrine changes in puberty?
- H-P-G (Hypothalamic gonadotropin-releasing hormone (GnRH)) synchrony
- Until puberty, neural mechanisms supress GnRH release
- At 6-9yrs, there is pulsatile nocturnal GnRH release
- Ovaries/testes become sensitised to FSH and LF
- ACTH stimulates the adrenals
Which hormone controls Sertoli cells?
FSH
Which hormone controls Leydig cells?
LH
What is testosterone converted into in the target organs?
DHT (dihydrotestosterone)
Describe the ovarian cycle
- Primary oocyte within follicle
- Follicle grows
- Follicle matures
- Follicle ruptures releasing a secondary oocyte (ovulation)
- Corpus luteum develops and then degenerates
What happens during the Follicular stage of the ovarian cycle?
Oestrogen levels rise and there is a surge of LH in the middle of the cycle. Ovulation occurs
What happens during the luteal phase of the ovarian cycle?
There is negative feedback after ovulation so that there is no more ovulation within that cycle
Which hormone upkeeps the endometrium?
Progesterone
What happens in Adrenarche?
ACTH stimulates the zona reticularis of the adrenal cortex which causes axillary and pubic hair growth.
What is the chronological order of puberty in girls?
Growth spurt Breast development Pubic hair Axillary hair Menarche
What is the chronological order of puberty in boys?
Testicular volume Penile length Pubic hair Growth spurt Axillary/facial hair Deep voice
Which development indicates puberty in a boy?
Increase in testicular volume (must be at least 4ml)
What is the age of precocious puberty in boys and girls?
Girls- 8ys
Boys- 9yrs
What is the age of delayed puberty in boys and girls?
Over 14years in both
What is Manuel Albright syndrome?
Presents as dark patches on the body. It can cause Girls to go through precocious puberty
What are some normal variants of puberty?
Premature Thelarche or Adrenarche
Can present together
What is the difference between central and peripheral precocious puberty?
Central: True precocious puberty and it’s gonadotrophin dependent
Peripheral: Pseudo-precocious puberty and it’s gonadotrophin independent Eg. Ovarian cysts
What are some concerns raised by precocious puberty?
- Possible sinister underlying cause (boys: 80%)
- Emotional and psycho-social issues
- Early cessation of growth
What is a Hypothalamic hamartoma?
A benign growth on the hypothalamus
What is the treatment given for Precocious puberty?
A long-acting LHRH (luteinising hormone-releasing hormone) analogue
It stops further progression of puberty by blocking the axis
What is premature Thelarche?
Isolated breast development usually seen in children ages 2-3yrs
It’s a normal variant of precocious puberty
What is premature Adrenarche?
Isolated pubic hair development
It’s a normal variant of precocious puberty but it can be the first sign of puberty in some
What hormones cause pseudo-precocious puberty?
Androgens or oestrogens
What is Klinefelter syndrome?
When a boy has an additional X chromosome
What are the symptoms of Klinefelter syndrome?
- Behavioural problems
- Androgen deficiency
- Infertility
- Micro-genitalia
What treatment if given to people with Klinefelter syndrome?
Lifelong testosterone replacement therapy
What are the symptoms of Turner’s syndrome?
Triad- short stature, streak gonads, and primary amenorrhoea
- Dysmorphic features like webbing of the neck and cubitus valgus
- Coarctation of aorta
- Horse-shoe kidneys
- Lymphedema
What is cubitus valgus?
The forearm is angled out away from the body when the arm is fully extended
What is Lymphedema?
Build up of fluid in soft tissue due to blocked lymph nodes
