Endocrine control of Growth Flashcards
Phases of growth
- fetal
- postnatal
- pubertal
- Adulthood
- Senescent
Compensatory growth
if you lose a kidney the other one hypertrophies until it can make up for the loss.
Catch-up growth
kid with illness has slow growth, once healed….catches up to normal growth rate
psychosocial deprivation
kid is in a home where no one likes him…growth slows….decrease caused by low growth hormone production
Growth hormone changes height by what percentage?
20-30%
Excess growth hormone leads to
Gigantism…height procedes to maximal genetic potential
Growth hormone deficiency
Dwarfism
KNOW TABLE 3: Effects of hormonal excess or deficiency on growth and development
ok
Excess and deficient growth hormone on skeletal maturation?
Normal in excess. Delayed in deficiency
Thyroid deficiency on skeletal maturation
delayed
Cortisol excess on skeletal maturation
delayed
Somatotropin
GH
Somatomedin
Mediates some GH actions, particularly on bone elongation and adipocytes, also known as IGF-1
Somatostatin
hypothalamic peptide that prevents GH secretion
Somatocrinin
hypothalamic peptide that stimulates GH…GHRH
WHat are the two structures of GH?
22k form . this promotes growth and other metabolic actions
20k: only growth promoting
Hyposomatotrophic dwarfism
Purely a GH deficiency
Panhypopituitarism?
Lacking all of the pit hormones
Major actions of GH on: Body mass
Increases it in the juvenile and pubertal periods
GH on tallness:
Increases it during juvenile and pubertal periods
Gh contributes to bone thickening which means that if GH goes unregulated you can get
acromegaly
GH on fat metabolism?
inc in lipolysis, seen as an increase in FFA
GH on carbohydrate metabolism
mildly impairs glucose uptake and utilization
Somatomedin (IGF-1) hypothesis KNOW
GH acts on liver —> IGF-1 secreted—> long bones–> growth
Dual Effector Hypothesis KNOW
GH–> bones, muscle, adipose tissue etc..(DIRECT)
GH—> liver—> hepatic effects–> IGHF-1 incr
What effect does T3 have on GH function
It enhances it by:
- increasing sensitivity to GH-RH
- Increasing synthesis
- Increasing Responsiveness
Cortisone on GH
Depletes the effect of GH
What is the best way to measure a person’s GH since it waxes and wanes?
IGF-1! KNOW THIS
