Puberty, Sexual Differentiation

Question 1

GnRH

Answer 1

• decapeptide (10aa)
• prod in arcuate nucleus
• pulsatile release
• neurons start in nose and migrate thru forebrain

Question 2

GnRH secretion is governed by

Answer 2

kisspeptin

Question 3

classification of sexual maturity

Answer 3

tanner classification

Question 4

the HPO axis becomes quiescent

Answer 4

4-6 weeks after birth

Question 5

adrenarche

Answer 5

6-8 yr

Question 6

thelarche

Answer 6

breast development

10 yr

Question 7

In the 5 years prior to puberty, gonadotropin levels are

Answer 7

low

very sensitive negative feedback system

Question 8

leptin role in puberty

Answer 8

affects maturation of GnRH pulse generator

assoc w/ initiation of puberty

Question 9

Kallman’s

Answer 9

adrenarche occurs despite absence of gonadarche

impaired migration of GnrH neurons to hypothalamus

Question 10

Addison’s

Answer 10

gonadarche despite absence of adrenarche

Question 11

Precocious puberty

Answer 11

gonadarche precede adrenarche

Question 12

major determinant of timing of puberty

Answer 12

genetics

Question 13

GnRH dependent causes of precocious puberty

Answer 13

• central nervous system tumors
• hypothalamic hamartoma
• craniopharyngiomata
• gliomata
• metastatic disease
• arachnoid or suprasellar cysts
• CNS infec/inflamm/injury

Question 14

GnRH independent causes of precocious puberty

Answer 14

• exogenous sex steroid admin
• primary hypOthyroidism
• ovarian tumors
• simple ovarian cyst
• adrenal tumors

Question 15

hypERgonadotripic hypOgonadism

Answer 15

gonadal dysgenesis (Turner’s syndrome)

Question 16

hypOgonadotropic hypOgonadism

Answer 16

• constitutional delay
• kallmann
• anorexia, extreme exercise
• pituitary tumors
• hyperprolactinemia
• drug use

Question 17

anatomic causes of delayed puberty

Answer 17

mullein agenesis
imperforate hymen
transverse vaginal septum

Question 18

Kallmann Syndrome in Females

Answer 18

anosmia
amenorrhea
hypOplastic olfactory tracts
arcuate nucleus does NOT secrete GnRH

Question 19

Kallmann Syndrome in Females

tx

Answer 19

steroid hormone replacement

Question 20

Turner syndrome

Answer 20

45XO
streak gonads
absent follicles 
primary amenorrhea 
short stature 
webbed neck
shield chest
widely spaced nipples 
high arched palate

Question 21

Marked LOF mutations of the 21-hydroxylase gene

Answer 21

congenital adrenal hyperplasia

21-hydroxylase –> cortisol prod

hyperkalemia, hypOtensive

Question 22

complete androgen insensitivity syndrome

Answer 22

• external female, blind vaginal pouch

- no internal structures at all

Question 23

5 alpha reductase deficiency

Answer 23

AR
46XY with ambiguity genitalia
internal male (undescended testes –> sertoli –> AMH –> mullein degen –> blind ending vagina

Question 24

mixed gonadal dysgenesis

Answer 24

chromosomal abnormality causes a child to be born w/ 2 different gonads

2nd most comm cause ambiguous genitalia

most cases of MGD involve mosaicism (46XY, 45XO)