Growth Stats Flashcards
(25 cards)
how do you measure bone growth, what life event is bone growth the best indicator of?
an x-ray of the (conventionally) left wrist shows the ossification pattern of the epiphyseal plate which reveals bone age;
it is the best indicator of puberty: 10-11 girls, 12 boys
body compartment growth to adulthood?
muscle: 33 fold
bone: 23 fold
cardiac muscle: 19 fold
liver, kidney, skin: 10 fold
brain: 3 fold
growth rates for childhood/puberty
prenatal: 130 cm/yr 0-6 months: 18-22 cm/yr (all cm/yr) 6-12 months: 14-18 second year: 11 third year: 8 puberty: 10-12 cm/yr
what are the most critical steps in measuring growth?
accuracy and repetition
what’s the difference between cross-sectional and longitudinal studies?
cross sectional will produce a smoother curve with more data points; longitudinal maybe more accurate but with a much more convoluted curve
what are the equations for BMI?
English: Weight (lb)/height (in.) ^2 x 703 Metric weight (kg)/height (cm) ^2 x 10k
which hormones cause advanced bone age?
TH, estrogen, androgens, corticosteroids
the lack of which hormones cause retracted bone age?
GH, TH
when is crossing percentiles common? when is it uncommon?
it’s common after birth until 3 years and then at puberty
it’s uncommon between 3 years and puberty
what is birth height/weight a relevant indicator of?
health of the intrauterine environment
how do you calculate (formula) mid-parental height?
((Father-5) + Mother)/2 : girls
((mother+5) + father)/2: boys
+/- 4 in.
how much nutritional intake is devoted to growth?
2-13%
what is the role played by hormones in growth?
catalysts, not activators
IGF Facts: function releasing hormone biochemical length serum level half-life method of circulation
anabolic hormone: uptake of amino acids by muscle to promote muscle growth
released by GH in liver
70 aa in length
serum levels are 100-1000 ng/ml
long half-life (days)
circulates bound to IGFBP3: IGFBP3 is responsible for its long half-life
IGF has a high homology to what other common hormone? what’s the difference?
insulin; IGF maintains it “C” segment which is truncated when compared with insulin’s; it also has a short “D” segment attached to the “A” segment
what effect do sex steroids have on growth? what does estrogen do?
sex steroids in general promote GH release, estrogen specifically promotes the closure of epiphyseal plates
what is late bloomer syndrome
characteristic to men, don’t get pubertal growth spurt until early college years (10th % to 50th %); seems to be genetic
what is familial short stature
genetic predisposition to just being in the 5th or slightly lower %, but steady throughout life, so no real disorder
what two genes are transcription factors for the synthesis of GH (and TSH, prolactin)
PIT-1, PROP-1
what TWO hypothalmic regulators influence the secretion of GH? what nuclei do they come from?
GHRH and somatsostatin; GHRH is arcuate nucleus and somatostatin is the PVN
what percentage of the ant. pituitary is made up of somatotrophs?
50%
when do you see the greatest spikes in GH levels? which sex has higher values?
during sleep - those on shift work have high peaks when they sleep, regardless of circadian clock; women;
what hormone from the GI tract can cause the release of GH?
ghrelin
what is the metabolic activity of GH?
it inhibits glucose metabolism and increases the breakdown of adipose tissue into FFA’s
