postnatal and child development Flashcards
effects of genetics on prenatal
minor affects overall
maternal size important in determining birth size
paternal genetic factors have little effects on birth
maternal genetic factors override fetal genetic factors in determining prenatal growth
effects of genetics on post nasal growth
largely determines final adult height
sex chromosomes have an affect
XY boys are taller than XX girls
endocrine effects on prenatal
insulin and insulin like growth factors are major prenatal hormones influencing growth
-IGF2 most important for embryonic growth
-IGF1 most important for later fetal and infant growth
growth hormone has no effect on early growth
endocrine effects postnatally
human growth hormone is the major hormone controlling growth after birth
nutritional affects prenatal
placenta provides all nutrients for growing fetus therefore essential for growth
placental insufficiency for most common cause of intrauterine growth restriction
placenta also controls hormones necessary for fetal growth
maternal diet affects nutritional availability
nutritional effects on postnatal
adequate nutrition is essential for growth
starvation due to a lack of substrate availability as can limit growth potential
obesity occurs due to an excessive intake of food
poor nutrition may delay onset of puberty
malabsorption of nutrients may cause reduced growth
environmental affects on prenatal
uterine capacity and placental sufficency important in providing optimal environment for fetus
placental function is more influential in fetal growth than uterine capacity
environmental affects on postnatal
socieeconomic status
chronic disease
emotional status
altitude mediated by changes in oxygen levels
postnatal growth periods
fetal growth period (30 percent of adult height) depends on uterine environment
infantile (15 percent of adult height which depends on nutrition good health and happiness and thyroid hormones)
childhood which is 40 percent of adult height and depends on growth hormones thryoid hormones genes and good health and happiness
pubertal which is 15 percent of adult height dependant on testosterone and oestrogen and growth hormone
rate of head growth
head is large for the body (1/3 in comparison to 1/7 as an adult)
grows rapidly in first 2 years before slowing
cranial sutures open at birth and close by 18 months
fetal phase
fastest period of growth over life course
30 percent of height
fetus doubles repeatedly in size over gestation
growth mainly driven by hypertrophy during fetal life
42 cycles of cell division before birth
only 5 further cycles from birth to adult hood
infantile phase
Covers 0-18 months after birth,
Accounts for approximately 15% of eventual height.
Rapid, but decelerating growth (vs fetal phase)
Length increases by 50%, head circumference by 30% and weight triples vs birth
Growth largely nutrition dependent
childhood phase
Covers 18 months to 12 years of age
Accounts for approximately 40% of eventual height.
Steady, slow prolongued growth
5-6 cm annual increase in height, and 3-3.5kg annual increase in weight
Good nutrition and health important, but endocrine growth regulation increasing
pubertal phase
Also known as the pubertal growth spurt
Contributes 15% of eventual height.
Rising levels of sex hormones boost hGH production
~25cm (XY boys) ~20cm (XX girls) increase in height over 3-4 years
Temporary growth spurt as sex hormones also cause fusion of growth plates
hormone changs over childhood
sex steroid production occurs during pregnancy
peak at mid gestation (20 weeks)
mini puberty in neonatal stage
then adolescence where hormones triggered again
mini puberty
Gonadotrophin secretion commences towards the end of the first trimester, peaks mid-pregnancy, then declines
HPG axis is transiently activated after birth (mini-puberty), after release from restraint by placental hormones
Continues for around 6 months after birth before declining
whats the point of mini puberty
Elevated sex steroids in males during mini-puberty seems to be important for normal gonadal development (testicular tissue and penile development)
Role of minipuberty less clear in female infants
Estradiol levels fluctuate through first few months after birth
Follicular development occurs in the ovary
Important for patterning and development of mammary tissue?
Elevated sex steroids in minipuberty may also influence programming of body composition and linear growth.
High testosterone levels in boys during minipuberty, may partly explain the higher growth velocity observed in boys compared to girls.
what triggers puberty
Control of puberty onset remains unclear, but influenced by metabolic status.
Release of neurokinin KNDy neurons may regulate release of Kisspeptin peptides, which act on GnRH neurons (KISS1R) to promote pulsatile GnRH release
Mutations in KISS1R affect puberty timing, implicating Kisspeptin-KISS1R signalling in regulation of this process.
developmental lifestones during puberty
The developmental events of puberty typically follow a predictable pattern
Compliance with this sequence is known as consonance.
Age of menarche decreased by ~4 years 1850-1960, then by a further 3 months per decade from 1977-2013
milestones during ouberty
females-breast budding,growth of pubic hair (peak),menacrche,growth of underarm hair,change in body shape and adult breast size
males-growth of scrotum and testes change in voice lengthening of penis growth spurt (peak) change in body shape
devlopmental domains
gross motor skills
fine motor skills
speech language and hearing skills
social behaviour and play skills
gross motor skills
6-8 weeks raise head in 45 degree
6-8 months sit without support (round back) and at 8 months sit with straight back
8-9months crawl
10 months cruise around furniture
12 months staggering walk
15 months steady walk
fine motor skills
6 weeks follow object by moving head
4 months reaches out for toys
4-6 months palmar grip
7 months transfers toys from one hand to the other
10 months mature pincer grip
16-18 months makes marks with crayons
14 months to 4 yrs building
2-5 yrs shapes w crayons
language skills
newborn loud noises
3-4 months vocalises alone or when spoken to
7 months turn to soft osunds out of ight
7-10 months sounds used undiscrimatory or at 10 used discriminatory when talking to parents
1 yer words
18 months can recognise body parts
20-24 months can make simple phrases
24+sentences
social/behavioural skill
6 weeks smile
6-8 months put food in mouth
10-12 months waves and plays peek a boo
12 months drinks water with two hands from a cup
18 months-holds spoon and gets food safely to mouth
18-24 months symbolic play
2 years dry by day and pull of clothing
2.5-3 years parallel play interactive play evoking taking turns
