principles of growth Flashcards
what 4 periods can growth be divided into
intrauterine, infancy, childhood, adolescence.
nonpathological factors affecting growth
genetics, age, sex, nutrition, socioeconomic status, environmental influences.
what is meant by intrauterine environment
placental function (the nutrient supply!), maternal size and length of gestation.
what determines size at birth
Genetics and the intrauterine environment
after the first year of life what is the major determinant of of growth
life environment and nutrition
later on in childhood what is the major determinant of of growth
thyroid and growth hormone will largely determine growth and problems here if there are any will be picked up
At puberty and into adulthood what is the major determinant of of growth
the sex steroids will shape secondary sexual characteristics and further growth.
actions of Growth Hormone
ncreasing lipolysis, protein synthesis and gluconeogenesis it stimulates release of IGF-1 from the liver
effect of IGF-1
its effects on chondrocytes and growth plate of bones.
endocrine drivers at fetal/infant
Insulin and IGF2
endocrine drivers at child
Growth hormone and IGF1
endocrine drivers at adolescent
Growth hormone and sex steroids
gestational week 10-12 what happens
- tooth buds appear, these will form the baby teeth
- limbs are long and thin
- foetus can make a fist with its fingers
- genitals appear well differentiated by this point
- Erythrocytes start to be produced in the liver and heartbeat can be detected by ultrasound
gestational week 13-16 what happens
At week 15, the main development of external genitalia is complete
gestational week 22 what happens
- The foetus reaches a length of 28cm and weighs about 500g
- The eyebrows and eyelashes are well formed and all of the eye components are developed
- The foetus now has the startle reflex
- Footprints and fingerprints continue to form
- Alveoli forming in the lungs
gestational week 24 what happens
- nervous system develops enough to control some body functions
- Eyelids open and close
- cochlea are developed, though the myelin sheaths develop until 18 months after birth
- respiratory system while immature, has developed to the point where gas exchange is possible
gestational week 30 what happens
- amount of body fat rapidly increases.
- rhythmic breathing movements occur but the lungs are still not fully mature
- thalamic brain connections that mediate sensory input from the periphery form
- The bones of the foetus are fully developed but are still soft and pliable (flexible)
gestational week 34 what happens
- The lanugo (fine, soft hair) begins to disappear
- Body fat increases
gestational week 35-39 what happens
- It will have no lanugo except on the upper arms and shoulders
- Small breast buds are present on both sexes
some growth factors in fetal life
- Insulin like growth factors (IGF1 and IGF2
- fetal insulin
- fetal glucocorticoid
- thyroid hormone
role of Insulin like growth factors (IGF1 and IGF2) in fetal life
IGF1 in foetal plasma is positively correlated with foetal weight
role of fetal insulin
important in growth as involved in creating energy stores (foetal hyperinsulinaemia leads to macrosomia).
modulates the expression of foetal IGF
role of fetal glucocorticoid
role in foetal lung maturation by stimulating production of surfactant.
involved in prenatal development of the liver in controlling blood glucose (glycaemia).
role of thyroid hormone in fetal life
Foetus can get thyroid hormone maternally or synthesise its own. It is essential for normal foetal brain development
