physiology and regulation of puberty W9

Question 1

physical changes in puberty?

Answer 1

increase in body mass, height, strength
CNS growth
completion of brain development
heart, lungs, viscera increase size/mass
regression of lymphoid tissue
enlargement of reproductive organs
apocrine sweat glands activated
development of pubic hair

Question 2

psychological changes in puberty?

Answer 2

activation of social and motivational tendencies
development of personal and sexual identity
abstract thinking
introspection
establishment of system of values
autonomy and personal independance
focus and increased importance on peer relationships
development of coping strategies

Question 3

what controls the onset of puberty?

Answer 3

HPG axis activation (activated by complex neuroendocrine systems)

Question 4

what is adrenarche and when does it occur

Answer 4

pre-pubertal awakening of the adrenal gland
adrenal androgen precursors are converted to sex steroids

Question 5

adrenal androgen precursors?

Answer 5

DHEA, DHEA-S, androstenodione

Question 6

physical signs of adrenarche?

Answer 6

public/axillary hair development, axillary odour, acne

Question 7

does absence of adrenarche prevent gonadarche?

Answer 7

no!

Question 8

when does gonadarche begin and what occurs?

Answer 8

age 8-14 years. onset of true central puberty.
increased pulsatile release of GnRH from the hypothalamus (leads to increased pituitary release of gonadotrophins LH and FSH
breast development and growth of ovaries (estradiol and progesterone production). growth of testes (testosterone production)

Question 9

girls vs boys time of puberty onset? variable duration?

Answer 9

girls onset at 8-13 years
boys onset at 9-14 years
variable duration of 3.5-4.5 years

Question 10

name for development of public hair?

Answer 10

pubarche

Question 11

name of onset of female breast development?

Answer 11

thelarche

Question 12

name for onset of menstruation? when does this occur in relation to thelarche?

Answer 12

menarche
2 years after thelarche

Question 13

name of onset of sperm emission?

Answer 13

spermarche

Question 14

when do growth spurts occur?

Answer 14

girls - tanner stage 2-3 (before menarche)
boys - tanner stage 3-4

Question 15

tanner stage 1 in girls?

Answer 15

elevation of papilla
villus hair only
2-2.4 inches per year
adrenarche and ovarian growth

Question 16

tanner stage 2 in girls?

Answer 16

breast bud under the areola, areola enlargement
sparse hair along labia
2.8-3.2 inches per year
clitoral enlargement, labia pigmentation, growth of uterus

Question 17

tanner stage 3 in girls?

Answer 17

breast tissue grows but has no contour or separation
coarser hair curled pigmented covers the pubes
3.2 inches per year
axillary hair, acne

Question 18

tanner stage 4 in girls?

Answer 18

projection of areola and papilla, secondary mound formation
adult hair, does not spread to thigh
2.8 inches per year
menarche and development of menses

Question 19

tanner stage 5 in girls?

Answer 19

adult-type contour, projection of papilla only
adult hair, spreads to medial thigh
cessation of linear growth
adult genitalia

Question 20

tanner stage 1 in boys?

Answer 20

testes <2.5cm
villus hair only
2.0-2.4 inches per year
adrenarche

Question 21

tanner stage 2 in boys?

Answer 21

testes 2.5-3.2cm, thinning and reddening of the scrotum
sparse hair at penis base
2.0-2.4 inches per year
decreases in body fat

Question 22

tanner stage 3 in boys?

Answer 22

testes 3.304cm, increase in penis length
thicker curly hair spreads to the pubis
2.8-3.2 inches per year
gynecomastia, voice break, increased muscle mass

Question 23

tanner stage 4 in boys

Answer 23

testes 4.1-4.5cm, penis growth, darkening of scrotum
adult hair does not spread to thighs
4.0 inches per year
axillary hair, voice change, acne

Question 24

tanner stage 5 in boys?

Answer 24

tests >4.5cm, adult genitalia
adult hair spreads to medial thigh
deceleration, cessation of linear growth
facial hair, muscle mass increases

Question 25

neurotransmitters affects on GnRH?

Answer 25

childhood - inhibitory pathway predominant puberty initiation - inhibitory pathway decreases augmentation of the excitatory tonus

Question 26

which neuropeptides are essential parts of controlling pubertal onset

Answer 26

kisspeptin neurons and co-expressed neuropeptides neurokinin B and dynorphin

Question 27

KNDy neuron?

Answer 27

kisspeptin/neurokinin B/dynorphin A neuronal ensemble

Question 28

what do KNDy neurons do?

Answer 28

express kisspeptin, and intermittently send stimulatory signals to GnRH neurons to generate a pulsatile GnRH secretion pattern kisspeptin binds to the G-protein coupled receptor (KISS1R) expressed by GnRH neurons to initiate a sequence of downstream events.

Question 29

difference in male/female feedback to kisspeptin?

Answer 29

males - stimulates LH release females - effect dependant on phase of menstrual cycle

Question 30

what controls upstream regulators of kisspeptin?

Answer 30

dunno

Question 31

how do genetic factors regulate onset of puberty?

Answer 31

networks of functionally related, hierarchically arranged genes regulate the neuroendocrine control of puberty initiation. transcription regulators likely direct expression of key subordinate genes to coordinate puberty initiation genetics explain 50-80% of variability in timing

Question 32

how do metabolic factors regulate onset of puberty?

Answer 32

leptin appears to play a permissive role in puberty initiation and maintenance of reproductive function (eg earlier initiation of puberty seen in obese children may be partly explained by higher leptin levels)

Question 33

how do environmental factors regulate onset of puberty?

Answer 33

the age of pubertal onset has been declining since mid-1990s - possible environmental causes?

Question 34

3 categories of puberty disorders

Answer 34

precocious puberty delayed puberty contrasexual development

Question 35

precocious puberty?

Answer 35

early development of secondary sexual characteristics (before 8 yrs in girls and 9 yrs in boys)

Question 36

causes of precocious puberty?

Answer 36

variant of normal development premature adrenarche, CNS/pituitary lesions, McCune-Albright syndrome, gonadotropin-secreting tumours or exogenous sex hormones

Question 37

delayed puberty?

Answer 37

absence or incomplete development of secondary sexual characteristics by 13 yrs in girls and 14 years in boys

Question 38

causes of delayed puberty?

Answer 38

variant of normal development hypogonadotropic hypogonadism, hypopituitarism, chromosomal abnormalities, hypothalamic dysfunction due to secondary causes

Question 39

contrasexual development?

Answer 39

when male or female children develop physical features of the opposite gender

Question 40

causes of contrasexual development

Answer 40

polycystic ovaries, increased adrenal gland responses, other endocrine pathologies estrogen secreting tumours in boys

Question 41

who is contrasexual development more prevalent in?

Answer 41

girls!