Changes from birth to adulthood

Physiology: Cognitive MilestonesMonth 3-5: Attends to and reaches for objectsMonth 4-8: Pulls string to secure a ringMonth 8-15: Imitates patting dollMonth 14-20: Finds Hidden ObjectMonth 18-28: Completes simple puzzles

Physiology: Language MilestonesMonth 1.5-3: SquealsMonth 3.5-8: Turns to locate a voiceMonth 9-13: Says Mama or DadaMonth 14-24: Combines two different wordsMonth 21-36: Uses plurals

Physiology: Fine Motor MilestonesMonth 2.5-4: Grasps rattleMonth 4.5-7: Transfers cube hand to handMonth 8-12: Has neat pincer graspMonth 15-20: Builds tower of four cubesMonth 18-24: Imitates vertical lineMonth 28-36: Copies circleBy age 5 years: Draws a squareBy age 5.5 years: Tripod pencil graspBy age 7 years: Draws diagonal lineBy age 9: Draws cross with same dimensionsBy age 12: Draws three dimensional cube

Physiology: Self Help MilestonesMonth 4.5-8: Feeds self crackersMonth 10-14: Drinks from cupMonth 13-19: Removes clothesMonth 18-28: Washes and dries handsMonth 30-42: Dresses without supervisionAttained on average by age 4.5 years

Rides a Bicycle with training wheelsCuts paper with scissorsColors inside lines

Attained on average by age 5.5 yearsTies shoelacesPrints first and last names

Attained on average by age 6 yearsRides a Bicycle without training wheels

Physiology: Gross Motor Milestones

Month 2-4.5: Rolls OverMonth 5-8: Sits without supportMonth 10-14: Stands AloneMonth 14-20: Walks up stepsMonth 21-28: Pedals tricycleMonth 30-44: Balances on one footBy age 6: Rhythmic skippingBy age 8.5: Alternates foot-hop in placeBy age 10: Holds tandem stance for 10 sec (eyes closed)

Physiology: Social and Emotional Milestones

Month 1.5-4: Smiles at othersMonth 4-9: Seeks primary caregiverMonth 8-15: Stranger anxietyMonth 10-15: Displays 2 or more recognizable emotionsMonth: 11-20: Exploratory play by selfMonth 21-36: Cooperative play in small groups

Growth in Length and Stature

Growth in Body Weight

http://www.healthforallchildren.co.uk/?SHOP=HFAC4&DO=USERPAGE&PAGE=PLOTCHART

The characteristic pubertal growth spurt results mainly from the synergetic effect of:gonadal sex steroids, growth hormone, and IGF-I production, with all showing a significant increase at the time of pubertal growth acceleration.

Insulin is also important for normal growth. Plasma insulin levels increase throughout childhood, but the rise is particularly pronounced during puberty with a strong positive correlation with IGF-I.

•Growth hormone-releasing factor (GRF) levels and GH secretion increase considerably during puberty, mainly at night •The amplitude of GH peaks increases early in puberty IGF-I is an important modulator of growth during childhood and adolescence

•Adrenal androgens seem to have no physiological role in normal growth

•Puberty of patients with isolated GH deficiency is frequently delayed, Leydig cell function is diminished, and the response to chorionic gonadotropins is decreased

•GH administration can restore testicular responsiveness to LH and Leydig cell steroidogenesis

Sex steroids promote secondary sex characteristics in peripheral tissues, regulate GnRH neurons via a neuroendocrine feedback loop and facilitate social behaviors by acting on central neural circuits. The pubertal increase in GnRH neuronal activity and episodic gonadotropin secretion is grossly timed by a developmental clock and fine-tuned by the neural integration of multiple permissive internal and external signals. At the onset of puberty, steroid feedback and steroid-independent neural mechanisms are engaged to disinhibit and excite GnRH neurons.

Sisk et al. Nature Neuroscience 2004

Permissive signals (related to energy balance):Body fat

Leptin

Insulin

Melatonine

•Peptide hormone•Regulates food intake and energy expenditure at the hypothalamic level (satiety factor)•Expressed predominantly in adipocytes•Regulated by body weight and nutrition•Involved in the regulation of GnRH secretion•Permissive factor for puberty (48kg)•Interacts with insulin, IGF1, GH and glucocorticoids

After birth the gonads respond to stimuli such as:

•LH-in boys up to the age of 6 months•FSH-in girls up to the age of 12-24 months

•In prepubertal children, no significant luteinizing hormone (LH) or follicle-stimulating hormone (FSH) response to intravenous or subcutaneous administration of GnRH is observed.

•During adolescence, the LH response to GnRH increases progressively in both sexes.

•The increase of FSH is much less marked than that of LH. •The primary triggering mechanism that initiates the activation

of the hypothalamic-pituitary-gonadal axis at puberty is still hypothetical.

activation of the hypothalamic-pituitary-gonadal axis:•induces and enhances the progressive ovarian and testicular sex hormone secretion •responsible for the profound biological, morphological, and psychological changes to which the adolescent is subjected

sex steroid production:•appearance and maintenance of sexual characteristics •capacity for reproduction

•In girls, circulating FSH levels increase progressively from 10 to 11 years of age, approximately 1 year prior to those of LH

•Thereafter, gonadotropins continue to increase throughout puberty, but important fluctuations are observed in relation to the menstrual cycle.

•In boys, a significant increase in both plasma FSH and LH is also found from the onset of puberty, closely linked to the rapid increase in testicular size characteristic of this pubertal stage.

•A further significant increase in circulating gonadotropins is also observed at late puberty

Puberty statistics

GIRLS BOYSBeginning of puberty 10.9 years (8.5-13.3) 11.2 years (9.2-14.2)

Growth spurt 12.2 years 13.9 years

Years of puberty 2-3 years 3-5 years

Menarche/Voice deepening 12.9 years (10-15) 14.6 years (12-17)

Physiological changes in puberty

http://www.youtube.com/watch?v=2zncsnYFGGQ&feature=channel

• Describe the hormonal changes involved in the growth spurt which is one of the main characteristics of puberty in both girls and boys. (Schematic drawing of a sequence of events is encouraged).